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'[ot]: how does a radar detector work?'
2001\10\22@171557 by rad0

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having a bit of a p_ _ _ _ _ g contest here....

does a radar detector emit anything?  I can't see why it
needs to, to 'detect' a police speed radar machine....?


thanks..

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2001\10\22@173649 by Dale Botkin

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On Mon, 22 Oct 2001, rad0 wrote:

> having a bit of a p_ _ _ _ _ g contest here....
>
> does a radar detector emit anything?  I can't see why it
> needs to, to 'detect' a police speed radar machine....?

A superheterodyne radar detector (most of them if I am not mistaken) has a
local oscillator, which it mixes with the received signal to detect the
presence of an incoming signal.  I'm told most can be detected, don't know
from what range though.  The signal radiated is unintentional "stray"
RF.  I've been planning to turn my old Cobra detector into a ham
transceiver, I'm told it's prety simple.  I just can't figure out what I'd
use to tune it, since 10G frequency counters don't grow on trees locally.

Dale

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2001\10\22@173701 by Douglas Butler

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No.  A radar detector is just a receiver.  The radar emits a pulse which
bounces off the target and back to the radar receiver.  A radar detector
receives the signal at the target, before the bounce.

Sherpa Doug

> {Original Message removed}

2001\10\22@173706 by Russell McMahon

picon face
> does a radar detector emit anything?  I can't see why it
> needs to, to 'detect' a police speed radar machine....?


Simple diode type detectors don't have to.
As soon as you use superheterodyne or any "tuned radio frequency" principals
which utilise signal frequency oscillations then there will be some leakage
which can be detected. Due to the relatively simple nature of many such
designs the control of spurious emissions is liable to be poorer than in
more conventional receivers.



   RM

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2001\10\22@174925 by Thomas C. Sefranek

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rad0 wrote:

> having a bit of a p_ _ _ _ _ g contest here....
>
> does a radar detector emit anything?

Yes.

Without a local LO trap, the Front end Local Oscillator radiates out the
receive antenna.

>  I can't see why it
> needs to, to 'detect' a police speed radar machine....?

You need to understand how a simple super-hetrodyne receiver works....

> thanks..
>
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2001\10\22@175330 by rad0

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alright...that's good enough for me...

I'm the wiz, I'm the wiz...and nobody beats me!!
just kidding   ;-)


think I'll go take a wiz...

----- Original Message -----
From: "Douglas Butler" <@spam@dbutlerKILLspamspamIMETRIX.COM>
To: <KILLspamPICLISTKILLspamspamMITVMA.MIT.EDU>
Sent: Monday, October 22, 2001 4:32 PM
Subject: Re: [ot]: how does a radar detector work?


> No.  A radar detector is just a receiver.  The radar emits a pulse which
> bounces off the target and back to the radar receiver.  A radar detector
> receives the signal at the target, before the bounce.
>
> Sherpa Doug
>
> > {Original Message removed}

2001\10\22@180501 by Bob Barr

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rad0 wrote:
>
>having a bit of a p_ _ _ _ _ g contest here....
>
>does a radar detector emit anything?  I can't see why it
>needs to, to 'detect' a police speed radar machine....?
>

The answer depends on the exact nature of the question:

1) Does the detector *need* to emit anything to operate?

No, it can detect incoming RF without necessarily emitting anything.


2) Might the detector emit anything while it's operating?

Yes, it may. If the detector uses superheterodyne mixing, the local
oscillator (and the IF mixing products) will almost certainly be emitted at
some level. (This is just a side-effect and is not needed for the detector
to work.)


As long as we're already [ot]:

Cardinal rule for p_ _ _ _ _g contests:

Take and hold the high ground for your position no matter what. :=)


Regards, Bob

_________________________________________________________________
Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp

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2001\10\22@181304 by David VanHorn

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>
> > No.  A radar detector is just a receiver.  The radar emits a pulse which
> > bounces off the target and back to the radar receiver.  A radar detector
> > receives the signal at the target, before the bounce.

Except that the radar dosen't emit pulses.
It emits a constant carrier, and the receiver is a homodyne.
The reflected carrier is doppler shifted a few 10's of Hz, and the output
of the receiver (actually a diode) is the doppler product.
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2001\10\22@204715 by artstar

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However the IF used within it (being a superheterodyne receiver) ends up
straying from the unit and rendering it detectable.

Adios,
LarZ

---------------  TAMA - The Strongest Name in Drums  ---------------

{Original Message removed}

2001\10\22@210011 by Craig R. Autio

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It is the L.O. (local oscillator), which typically swings from 11.8 GHz to
11.4ish GHz that radiates out the receive antenna.  This leakage is what is
"sniffed" by the radar detector-detector, also known as the VG-2 to uncover
the usage of a radar detector in areas where they are illegal.  Other
detectors radiate at other frequencies depending on the first L.O. and
I.F.'s used.  Depending on the level, they can be sniffed quite a
distance....


----- Original Message -----
From: rad0 <TakeThisOuTrden25EraseMEspamspam_OUTMINDSPRING.COM>
To: <RemoveMEPICLISTspamTakeThisOuTMITVMA.MIT.EDU>
Sent: Monday, October 22, 2001 5:15 PM
Subject: [ot]: how does a radar detector work?


> does a radar detector emit anything?  I can't see why it needs to, to
'detect' a police speed radar machine....?

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2001\10\23@045535 by Jonathan Luthje

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I think it's fair to say that *all* electronic equipment, whether it be a
radar detector, telephone, television, cd player, or whatever emits some
form of detectable emissions - it's just a matter of knowing what to look
for.

The wonderful people (full sarcasm intended) have developed the next
generation of RDD, which is apparently deadly accurate in picking up the new
"undetectable" units from Bell and companies of the like. The VG-2 was
sketchy at best, but this thing is MEAN ... especially if you want to avoid
a speeding ticket.  (http://www.stalcar.com.au)

So now you can get copped with a $1000-00 fine for having the unit in your
car ... damnit ...

Of course you could always hook up one of them 20MW broad spectrum pulse
discharge unit's to the roof and destroy all electronic equipment within a 1
mile radius .... may want to be careful of your ECU and stereo system though
.... and then there's always the problem of where to GET 20 megawatts from
.... I don't think the alternator in my vehicle is quite up to standard! :)


Regards,


J0n



{Original Message removed}

2001\10\23@075432 by Bob Ammerman

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> Of course you could always hook up one of them 20MW broad spectrum pulse
> discharge unit's to the roof and destroy all electronic equipment within a
1
> mile radius .... may want to be careful of your ECU and stereo system
though
> .... and then there's always the problem of where to GET 20 megawatts from
> .... I don't think the alternator in my vehicle is quite up to standard!
:)
>

How about a Mr. Fusion? IIRC it provides 1.8 GW.

Bob Ammerman
RAm Systems
(contract development of high performance, high function, low-level
software)

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2001\10\23@083226 by David VanHorn

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At 07:50 AM 10/23/01 -0400, Bob Ammerman wrote:
> > Of course you could always hook up one of them 20MW broad spectrum pulse
> > discharge unit's to the roof and destroy all electronic equipment within a
>1
> > mile radius .... may want to be careful of your ECU and stereo system
>though
> > .... and then there's always the problem of where to GET 20 megawatts from
> > .... I don't think the alternator in my vehicle is quite up to standard!
>:)
> >
>
>How about a Mr. Fusion? IIRC it provides 1.8 GW.

Only 1.21GW. You'd need two. :)

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2001\10\23@093407 by Ashley Roll

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Generating large EMP pulses is apparently not too difficult for the
sufficiently motivated.

http://www.infowar.com/mil_c4i/mil_c4i8.html-ssi

Ash.

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> {Original Message removed}

2001\10\23@154326 by Peter L. Peres

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Normal radar detectors do not emit anything but some advanced models use
a heterodyne method to scan the band(s) and that involves a low power
microwave oscillator (<10mW probably) tuned by voltage or by other means.

Peter

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2001\10\23@155357 by David VanHorn

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At 09:32 PM 10/23/01 +0200, Peter L. Peres wrote:
>Normal radar detectors do not emit anything but some advanced models use
>a heterodyne method to scan the band(s) and that involves a low power
>microwave oscillator (<10mW probably) tuned by voltage or by other means.

This is how even the most basic models work.
Makes them handy for converting into cheap microwave spectrum analyzers too. :)

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2001\10\23@190356 by DFansler

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The in the state of Virginia it is illegal to have a radar detector - they
must emit some radiation, because the police are capable of identifying cars
with radar detectors operating.

David V. Fansler
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http://www.DV-Fansler.com

{Original Message removed}

2001\10\23@191321 by Jim

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----- Original Message -----
From: "David V. Fansler" <RemoveMEDFanslerKILLspamspamMindSpring.com>
To: <PICLISTSTOPspamspamspam_OUTMITVMA.MIT.EDU>
Sent: Monday, October 22, 2001 9:10 PM
Subject: Re: [ot]: how does a radar detector work?


> The in the state of Virginia it is illegal to have a radar detector - they
> must emit some radiation, because the police are capable of identifying
cars
> with radar detectors operating.


... it's called "LO Leakage" and it's (surprise!) from
the LO (local oscillator) in the RADAR detector .. the
LO leakage is a functon of "mixer isolation" being poor
in the (functional) first mixer between the LO and
RF ports ... in all likelyhood this device is NOT
a doubly-balanced, three port mixer device (more likely
a single ended device like a simple diode mixer) and
will exhibit even *poorer* LO to RF port isolation ...


Jim

>

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2001\10\23@192508 by Jim

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 "Normal radar detectors do not
  emit anything"

Upwards of ten years ago - my 'Escort' model
was sold for just this purpose - to avoid
false reports caused by other model's LO
leakage. They called a "Statistical Operations
Processor" - STOP (not WOPR) for marketing
purposes. This was/is sold by the old
"Cincinati Microwave" (sp?) company.


I don't know what the current 'state of the
art' is, but I suspect they *must* use similar
techniques - "superhet" receiver involving the
use of an LO, but *perhaps* a lower leakage
mixer and/or filtering (a notch) in and around
the LO freq area somewhere in-line to the
antenna.

Jim


{Original Message removed}

2001\10\24@012508 by Brooke Clarke

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face
Hello:

Lower cost radar detectors have LO leakage.  I use a valentine V1 radar detector
and it often picks up the LO radiation of others radar detectors.  You can tell
by how the Valentine responds that it is not a police radar.  The valentine
itself is very well designed and does not emit any detectable LO radiation.
This is because Mike Valentine has been a member of the Old Crows for many
years.  (I was a member for over 25 years working on military microwave
stuff.).  For more see: http://www.valentine1.com  they used to have a photo of
the V1 sitting right in front of a Radar Detector Detector to demonstrate that
the V1 does not get detected.  I have no connection with them, only a very
satisfied customer.

Brooke

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2001\10\24@034602 by artstar

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However, the new Stalcar's here in Australia can pick up the V1 just as
easily as the super-leaky Bell unit.

VG2 cloaking isn't adequate in Australia any more.

Adios,
LarZ

---------------  TAMA - The Strongest Name in Drums  ---------------

{Original Message removed}

2001\10\24@081007 by Alan B. Pearce

face picon face
>The in the state of Virginia it is illegal to have a radar detector - they
>must emit some radiation, because the police are capable of identifying
cars
>with radar detectors operating.

>>No.  A radar detector is just a receiver.  The radar emits a pulse which
>>bounces off the target and back to the radar receiver.  A radar detector
>>receives the signal at the target, before the bounce.


The problem with diode detectors is that part of the rectifying process will
generate signals that will definitely be re-radiated, if not at the
fundamental then at a harmonic and these can be detected. The only way to
stop this is to use a circulator or some other form of coupler, and these
then are a lossy component in the path reducing the sensitivity of the
detector.

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2001\10\24@160149 by John Craft

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State of the art?

http://www.valentineone.com

Jc.


-----Original Message-----
From: Jim [KILLspamjvpollspamBeGonespamDALLAS.NET]
Sent: Tuesday, October 23, 2001 6:26 PM
To: EraseMEPICLISTspamEraseMEMITVMA.MIT.EDU
Subject: [ot]: how does a radar detector work?


 "Normal radar detectors do not
  emit anything"

Upwards of ten years ago - my 'Escort' model
was sold for just this purpose - to avoid
false reports caused by other model's LO
leakage. They called a "Statistical Operations
Processor" - STOP (not WOPR) for marketing
purposes. This was/is sold by the old
"Cincinati Microwave" (sp?) company.


I don't know what the current 'state of the
art' is, but I suspect they *must* use similar
techniques - "superhet" receiver involving the
use of an LO, but *perhaps* a lower leakage
mixer and/or filtering (a notch) in and around
the LO freq area somewhere in-line to the
antenna.

Jim


----- Original Message -----
From: "Peter L. Peres" <@spam@plp@spam@spamspam_OUTACTCOM.CO.IL>
To: <spamBeGonePICLISTspamKILLspamMITVMA.MIT.EDU>
Sent: Tuesday, October 23, 2001 2:32 PM
Subject: [ot]: how does a radar detector work?


> Normal radar detectors do not emit anything but some advanced models use
> a heterodyne method to scan the band(s) and that involves a low power
> microwave oscillator (<10mW probably) tuned by voltage or by other means.
>
> Peter
>

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2001\10\24@161833 by Peter L. Peres

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> The in the state of Virginia it is illegal to have a radar detector -
> they must emit some radiation, because the police are capable of
> identifying cars with radar detectors operating.

I don't know about Virginia but I read a book by one R.V.Jones called
"Most Secret War" that was most instructive wrt. $SUBJ in another context.
I am sure that they have made great progress meanwhile. NLJDs come to my
mind in this context. So they must not emit anything although it is
helpfull probably.

Peter

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2001\10\24@211210 by Jim

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I'm not particularly impressed - a lot of "bells
and whistles" are detailed and the dual (front and
rear facing) antennas are a nice feature, but *no*
real technical details are revealed: Sensitivity/MDS
(Minimum Discernable Signal) spec, antenna beamwidths/
pattern, LO leakage power, image rejection, First IF
frequencies, etc, as one would get with any other
hi-tech receiver.

I have a later version Escort that shows via a 1
line by 8 char (or is it 16?) LCD display both the 'frequency'
(by horizontal position in the LCD display) and the
strength of the 'emitter' as received - a crude
"spectrum analyzer" if you will. We've even used it to
tune up those cheapie X-band sources back into the center
of the 10.525 MHz 'motion detector' band ...

Jim


----- Original Message -----
From: "John Craft" <TakeThisOuTjcraft.....spamTakeThisOuTDIAMONDDATA.COM>
To: <TakeThisOuTPICLISTKILLspamspamspamMITVMA.MIT.EDU>
Sent: Wednesday, October 24, 2001 3:00 PM
Subject: Re: [ot]: how does a radar detector work?


> State of the art?
>
> http://www.valentineone.com
>
> Jc.
>
>
> {Original Message removed}

2001\10\26@195432 by Craig R. Autio

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face
Tony,

Any chance of you getting a sniff at a Stalcar with a domain analyzer?  We
have surmised at what the L.O.'s and I.F.'s are but would like to confirm.

Craig

From: Tony Antoniou
Subject: Re: [OT]: how does a radar detector work?


> However, the new Stalcar's here in Australia can pick up the V1 just as
> easily as the super-leaky Bell unit.
>
> VG2 cloaking isn't adequate in Australia any more.
>
> Adios,
> LarZ
>

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2001\10\26@204748 by artstar

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It is impressive in that it can detect the number of possible sources of
radar at any instant, and their bearing in relation to you, but despite
some sophisticated filtering, they still are easily detected by Stalcar
units - up to 1km away!

Adios,
LarZ

---------------  TAMA - The Strongest Name in Drums  ---------------

-----Original Message-----
From: pic microcontroller discussion list
[.....PICLISTspamRemoveMEMITVMA.MIT.EDU] On Behalf Of John Craft
Sent: Thursday, 25 October 2001 6:00
To: RemoveMEPICLISTspamspamBeGoneMITVMA.MIT.EDU
Subject: Re: [ot]: how does a radar detector work?

State of the art?

http://www.valentineone.com

Jc.

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2001\10\26@205130 by artstar

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Not necessarily. There is an Australian design which has superior
filtration without much sacrifice to the sensitivity. This one is
capable of detecting up to 1km away, and with low-power radar (used
primarily for photo-radar systems due to their close proximity nature of
operation), up to 300m as you approach the authority's vehicle from
behind, depending on how many other cars out there you can get a
reflection from. In a worst case scenario, you would get about 100m
warning which is still enough time to slow from say 90km/h to 50km/h
3#-)

Adios,
LarZ

---------------  TAMA - The Strongest Name in Drums  ---------------

{Original Message removed}

2001\10\26@205150 by artstar

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Probably next to f__k all of a chance, but I'll try 3#-)

Adios,
LarZ

---------------  TAMA - The Strongest Name in Drums  ---------------

{Original Message removed}

2001\10\26@231412 by Russell McMahon

picon face
Lessee - is this poacher turned gamekeeper turned poacher turned ..... ?? or
what.

Of course, you only want this information for legitimate non-directed
scientific research, dont you ? :-)



     Russell McMahon
_____________________________



{Quote hidden}

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2001\10\26@231417 by Russell McMahon

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> Not necessarily. There is an Australian design which has superior
> filtration without much sacrifice to the sensitivity. This one is
> capable of detecting up to 1km away, and with low-power radar (used
> primarily for photo-radar systems due to their close proximity nature of
> operation), up to 300m as you approach the authority's vehicle from
> behind, depending on how many other cars out there you can get a
> reflection from.

>In a worst case scenario, you would get about 100m
> warning which is still enough time to slow from say 90km/h to 50km/h

Anyone who NEEDS to slow from 90 kph to 50 kph rightly deserves to meet an
"authority's vehicle" armed with something very substantially more harmful
than a radar unit. It continually amazes me that people are so in contempt
of the "social contract" implicit in a 50 kph speed limit, and therefore the
lives of their fellow citizens,  that they will unblushingly talk about
travelling at (probably in excess of) 90 kph in such an area, obviously with
no concern at all for the dangers they would be imposing on others they are
contracting with. At 90 kph your vehicle has over 3 times the energy it does
at 50 kph, proportionally greater stopping distance and a near certainty of
killing anyone it hits (whether you have started braking or not). [[
Probability of death for a pedestrian struck by a car is very very roughly

   Death probability = (V^2/50)%
                                                               V in kph.

For %ages above 100% you just get overkill :-(

The speed you will be doing when the car doing 50 kph would have stopped if
you both hit the brake pedal together is about sqrt(V^2-2500) or more
generally if the car doing V2 can JUST stop in time then the car doing V1
will still be travelling at sqrt(V1^2-V2^2) when it hits the
social-contractee.
In this case a car doing 90 kph at the start of braking will still be doing
around 75 kph when it hits a pedestrian that a driver doing 50 kph would
have just managed to stop for.
[[This is based on energy considerations and assumes that brakes are devices
that remove energy at a constant rate and that your high speed driver's
brakes do not fade and also does not allow for any reaction times which
makes the results even worse.]]

Anyone who countenances driving at 90 kph (+) in an area where people
(including, often enough, children) reasonably expect them to be driving at
somewhere around 50 kph and who uses instrumentation to allow them to
continue to do so deserves to have their social-contract-document (you may
call it a "licence") revoked for a long long time. Anyone who so values
making a personal profit and supporting the other guys freedom to attempt to
commit murder by making and selling him such instruments deserves a mix of
pity and contempt. Both deserve to spend considerable periods helping clean
up the carnage caused by idiots who think their "rights" to get where they
are going a truly insignificant time sooner, so over-ride the rights of
others in their community.

Lay on, "gentlemen".



       Russell McMahon

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2001\10\27@015631 by Patrick J

flavicon
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From: "Russell McMahon" <spamBeGoneapptech@spam@spamspam_OUTCLEAR.NET.NZ>
> Anyone who NEEDS to slow from 90 kph to 50 kph rightly deserves to meet an
> "authority's vehicle" armed with something very substantially more harmful
> than a radar unit. It continually amazes me that people are so in contempt
> of the "social contract" implicit in a 50 kph speed limit, and therefore the
> lives of their fellow citizens,  that they will unblushingly talk about
> travelling at (probably in excess of) 90 kph in such an area, obviously with
> no concern at all for the dangers they would be imposing on others they are
> contracting with.
[snip]

ok, this is one of those things u just cant defend w/o looking like a serialkiller.
Unfortunately we aren't all god's little angels that do what 'Big Brother' thinks
is right for some political or other stupid reason (ok, limit justified in some cases)

We have roads here that are 100% free line of sight and no reason for a stupid
50 km/h limit. For easy political points they set the limits low and none cares
about the limit since it doesnt make any sense to the ppl drivning there.

We recently were 'blessed' w 30 km/h limit outside schools, now doesnt that
sound good ? We never had any deaths infront of those schools and the
old system was good (go slow carefull if kids there. Leave it to ppl to jugde)
Now u must drive 30 even if there isnt any kids. And there never are, except
around school start/end and then only for  a few minutes... so stupid !
(And no, this doesnt mean I want to kill all kids :-)

</smelling like roses>
/$0.02

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2001\10\27@070610 by Russell McMahon

picon face
> > It continually amazes me that people are so in contempt
> > of the "social contract" implicit in a 50 kph speed limit, and therefore
the
> > lives of their fellow citizens,  that they will unblushingly talk about
> > travelling at (probably in excess of) 90 kph in such an area, obviously
with
> > no concern at all for the dangers they would be imposing on others they
are
> > contracting with.
> [snip]
>
> ok, this is one of those things u just cant defend w/o looking like a
serialkiller.
> Unfortunately we aren't all god's little angels that do what 'Big Brother'
thinks
> is right for some political or other stupid reason (ok, limit justified in
some cases)

Most cases in this country anyway, IMHO only of course.

> We have roads here that are 100% free line of sight and no reason for a
stupid
> 50 km/h limit. For easy political points they set the limits low and none
cares
> about the limit since it doesnt make any sense to the ppl drivning there.

Understood. But my observation is that in some areas the 50 kph limit makes
sense to me as an observer but clearly not to most of the drivers who pas
through. One bad case is a road which links two highways. It should never
have been allowed to run through a built up area but it was and there are
houses right by the road's edge. The limit is 50 kph and it is a fair one
due to the high pedestrian level and children present. At 50 kph you build a
vast queue unless you pull over occasionally.

> We recently were 'blessed' w 30 km/h limit outside schools, now doesnt
that
> sound good ? We never had any deaths infront of those schools and the
> old system was good (go slow carefull if kids there. Leave it to ppl to
jugde)
> Now u must drive 30 even if there isnt any kids. And there never are,
except
> around school start/end and then only for  a few minutes... so stupid !
> (And no, this doesnt mean I want to kill all kids :-)

OK. I can understand all the above and agree with the general principals. I
rather suspect though that the guys with the radar detectors who are happy
to do 90 in a 50 kph area may well do so anytime their electronic
anti-conscience says they can get away with it.
I, being a (to some extent) normal human being (some friends may tell you
otherwise :-) ) also do not stick absolutely to speed limits or behave in a
perfect manner in a motor vehicle. But the radar detector boys (and, to a
lesser extent, girls) are largely not concerned about technical violations
or stupid regulations - they largely just want to exercise their superior
driving skills and save a few of their valuable travelling minutes with no
concern for their fellow road users and without financial risk to
themselves.

In this country their doesn't seem to be too much stupidly applied speed
restrictions and radar traps in safe areas - the traffic (and other) police
levels have been run down to the level where they need all the time they can
get doing "real" policing. I am an enthusiastic driver - I love rough and
winding roads - who nonetheless drives with the intention (not always
achieving it) of observing the speed limits and I have not been stopped by a
traffic officer in more years than I can remember (may have something to do
with failing memory ??? :-) ). A radar detector would have done me no good
whatsoever in all those years but they are still good sellers here.

I have "run down" one pedestrian so far - a child who ran in front of my
motorcycle many years ago ("we all fall down"). No great harm done
fortunately but it does give you pause to think about the consequences.



regards


               Russell McMahon

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2001\10\27@103246 by Bob Barr

picon face


Patrick J wrote:

>[snip]
>
>ok, this is one of those things u just cant defend w/o looking like a serialkiller.
>Unfortunately we aren't all god's little angels that do what 'Big Brother' thinks
>is right for some political or other stupid reason (ok, limit justified in some cases)

>

I can only hope that the 90kph -> 50 kph example was an exaggerated case. To me, a 50 kph limit implies a residential/commercial area with pedestrians and cross traffic. Doing almost double the limit is, in that case, insane.

 

>We have roads here that are 100% free line of sight and no reason for a stupid
>50 km/h limit. For easy political points they set the limits low and none cares
>about the limit since it doesnt make any sense to the ppl drivning there.
>
>We recently were 'blessed' w 30 km/h limit outside schools, now doesnt that
>sound good ? We never had any deaths infront of those schools and the
>old system was good (go slow carefull if kids there. Leave it to ppl to jugde)
>Now u must drive 30 even if there isnt any kids. And there never are, except
>around school start/end and then only for a few minutes... so stupid !
>(And no, this doesnt mean I want to kill all kids :-)

>

In the US, many cities have dual-limit zones near schools. The normal limit may be 35mph but is reduced to 25mph (in some cities, 20mph) when children are proceeding to/from school. Some cities use flashing lights to indicate the reduced speed limit; others allow driver (and police) determination of when the reduced limit is in effect.

Regards, Bob


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2001\10\27@104330 by Dale Botkin

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> In the US, many cities have dual-limit zones near schools. The normal
> limit may be 35mph but is reduced to 25mph (in some cities, 20mph) when
> children are proceeding to/from school. Some cities use flashing lights
> to indicate the reduced speed limit; others allow driver (and police)
> determination of when the reduced limit is in effect.

Most here are 25, but one school here has a 15MPH limit.  Of course
speeding in a school zone carries a double penalty.

Once a couple of years ago I found myself in the "defensive driving"
class, which around here you can sometimes take to avoid having a traffic
violation show up on your insurance record.  They offer two classes, the
cheap ($40, two nights) class for minor violations and the not-so-cheap
($100, four nights) class for more major violations -- this is things like
20+MPH over the speed limit, etc.  There was a nice little old lady who
had to take the expensive class for doing 25MPH in a school zone - which
would have been perfectly legal in front af any schol in town except for
that one.  Oddly, that one particular school also has a very nice enclosed
pedestrian overpass with stairs and elevators at both ends, so there are
very rarely any kids near the street.

It's a small suburb, so most people recognize that particular unusually
low speed limit is there to generate revenue for the town.  I've got to
wonder if thats how they're paying for the overpass...

Dale

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2001\10\27@115302 by Gerhard Fiedler

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At 10:32 10/27/2001 -0400, Bob Barr wrote:
>In the US, many cities have dual-limit zones near schools. The normal
>limit may be 35mph but is reduced to 25mph (in some cities, 20mph) when
>children are proceeding to/from school. Some cities use flashing lights to
>indicate the reduced speed limit; others allow driver (and police)
>determination of when the reduced limit is in effect.

When I saw this first, it really surprised me how disciplined even
otherwise not so disciplined drivers observed school zones and stopped
behind school buses.

The rule to go slow only when children present is one of the examples of a
"responsible restriction" -- a somewhat odd, contradictory animal, but
something that gives hope: if we were all always responsible, we wouldn't
need a limit at all when children are present, but an "always on" limit is
still a step further.


A side fact: in the US, close to 40,000 people get killed each year in
traffic, mostly due to not adequate driver behavior, many due to too high a
speed for the circumstances. Which means to me that the current rules are
still way below what would be needed -- or that the human race is
inherently unable to drive safely :)  It's odd that we simply take this
number as a given -- the whole Vietnam war killed less than two years'
worth of US citizens' road death toll, over a period of ten years...

ge

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2001\10\27@230303 by Jim

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   " The rule to go slow only when children present
     is one of the examples of a "responsible restriction" "


In reality, it seems it has to do with the *much* stiffer
fines imposed as the penalty for such a violation (deduced
from having talked with those who live in abject fear of
seeing such a fine imnposed).

It's also the *prime* reason I observe those speed
restrictions. (It always seems that there are *no*
kids in sight 4 out of 5 times I'm proceeding through
those zones too.)

Jim





{Original Message removed}

2001\10\27@230933 by Jim

flavicon
face
   "Once a couple of years ago I found myself in
    the "defensive driving" class, which around
    here you can sometimes take to avoid having
    a traffic violation show up on your insurance
    record.  They offer two classes, ..."

There is another avenue - ask the judge about "Defferred
Adjudication" if you haven't got time to spend on the
classes (or want to save the forty some odd dollars).

The city will still collect their 'fine money' but if
you keep your record clean in that city for sixty (or 90?)
days - the record of the violation will never make it to
the state (that scheme works in some municiplities in
Tejas anyway).

Jim





{Original Message removed}

2001\10\28@192543 by Russell McMahon

picon face
>     " The rule to go slow only when children present
>       is one of the examples of a "responsible restriction" "
>
> In reality, it seems it has to do with the *much* stiffer
> fines imposed as the penalty for such a violation (deduced
> from having talked with those who live in abject fear of
> seeing such a fine imnposed).
>
> It's also the *prime* reason I observe those speed
> restrictions. (It always seems that there are *no*
> kids in sight 4 out of 5 times I'm proceeding through
> those zones too.)

It makes sense that children aren't present most of the time.
And this of course greatly raises the risk to them when they are present.
It's the old "familiarity breeds contempt" principle - if we almost always
find the danger isn't there (especially if it is a danger to someone else
and not to us) then after a while we tend to dismiss it as irrelevant and
ignore it. Not MANY children die at schools due to cars. Arguably (and some
will argue) even one is too many.

The only successful way found to deal with human nature seems to be to
ensure both that a danger is ALWAYS present and that the danger is to the
driver - hence the draconian penalties involved. From what people have been
saying here, it works. Ideally a more sensible solution should be available
but human nature tends to work against it.

Having said that, interestingly, in this country we do not have such
regulations at school crossings.
Maybe this confirms the excessive nature of the regulations in other
countries or maybe driver behaviour is different?
School patrols with swing out signs and compulsory vehicle stopping are
almost universal before and after school and this seems to produce the
desired result. Woe betide the driver who crosses a controlled crossing when
the school patrol signs are out! Why this should work here and not require
extra restrictions I don't know - I doubt that we value our children any
more or less here than elsewhere.

We do have regulations re overtaking stopped school buses and the occasional
tragedy when these are ignored.



regards


           Russell McMahon

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2001\10\29@052402 by Alan B. Pearce

face picon face
>We recently were 'blessed' w 30 km/h limit outside schools, now doesnt that
>sound good ? We never had any deaths infront of those schools and the
>old system was good (go slow carefull if kids there. Leave it to ppl to
jugde)
>Now u must drive 30 even if there isnt any kids. And there never are,
except
>around school start/end and then only for  a few minutes... so stupid !
>(And no, this doesnt mean I want to kill all kids :-)

Having had a child run out of a gateway into the side of my car while I was
doing 20mph, I cannot sympathise with your sentiments. You can bet your
bottom dollar that one day someone is going to do this to you right when you
least expect it. It happened to me in a deserted street, so just because you
see no-one around the school outside setdown and pickup hours means
nothing - my accident happened on a Saturday, the child was on way to school
for a sports event !!!!!!!

Having been involved in more than my fair share of accidents, only a small
proportion of them my fault, I can only applaud the attempts by the
authorities to make traffic move safer. If there is really a problem with a
speed limit that is unreasonable there are political ways to change things
which ensure that the resultant limit is still safer for everyone.

></smelling like roses>

I read this as "not smelling like roses".

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2001\10\29@173235 by Patrick J

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From: "Alan B. Pearce
> >We recently were 'blessed' w 30 km/h limit outside schools, now doesnt that
> >sound good ? We never had any deaths infront of those schools and the
> >old system was good (go slow carefull if kids there. Leave it to ppl to jugde)
> >Now u must drive 30 even if there isnt any kids

> Having had a child run out of a gateway into the side of my car while I was
> doing 20mph, I cannot sympathise with your sentiments. You can bet your
> bottom dollar that one day someone is going to do this to you right when you
> least expect it. It happened to me in a deserted street, so just because you
> see no-one around the school outside setdown and pickup hours means
> nothing

It means that it is very unlikely that a kid would materialise from thin air.
And from that u can draw the conclusion that its safer to drive there then,
compared to when its packed w playing kids.

> Having been involved in more than my fair share of accidents, only a small
> proportion of them my fault, I can only applaud the attempts by the
> authorities to make traffic move safer. If there is really a problem with a
> speed limit that is unreasonable there are political ways to change things
> which ensure that the resultant limit is still safer for everyone.

I have also had a couple of accidents, none of them my fault.
What you are saying would mean that the only way to be safe would be
to stop using cars alltogheter. No cars => no accidents w cars involved.

What I am saying is that there are risks that doesnt justify rules that
makes ppl haveto drive slow for the rare occasion that one day there
might me someone jumping out infront of your car. There are much
more pressing and dangerous situations to make more safe than this.
Each time you use your car you take a calculated risk.

We have never had a fatal accident infront of our schools here so
bearing that in mind its stupid to start setting even lower limits there
considering we have alot of ppl getting killed on other roads.
Why not start there ? (and what to do there is another thread :)

Also we send a message to the kids when we set the speed limit very
low outside schools compared to all other streets: "hey, cars are not dangerous,
they can always stop. The street outside the school is a good place to play"
Next day they are playing on another street and get killed because the cars
suddenly were comming much faster than they are used to from school-street.

</OT>
/PJ

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2001\10\30@125457 by M. Adam Davis

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So you want to keep the speed limit high until it does happen?  /Then/
when it happens you won't complain?  I'd guess that you'd still complain
and blame it on the kid or the driver, and say that normally it doesn't
happen so the limit should be high.  I'm just saying that I feel your
reasoning is flawed.  Perhaps there are better arguments for a high
speed limit, but they probably don't outweigh the benefits.

There is a concept called prevention.  It's better to make changes now
than reget problems later.  Besides, how often did you actually go at or
under the speed limit before it was lowered?  Did everyone else go under
the speed limit?

Maybe they are using your reasoning, saying that people are going to go
over the limit, so they might as well lower it so people actually do go
more slowly, and they can ticket people at 35KPH instead of 5 over the
previous limit.

Aside from all that nit-picking, studies show that at 25MPH (pretty
close to 30KPH) significantly fewer deaths result due to car accidents
than at the next higher speed.  It's not a matter of 'if' someone will
be run into, it's a matter of 'when' and how bad it's going to be.  At
30KPH most people live no matter how they were hit.

Quite frankly I'm surprised that the speed limit was higher around the
school previously.  All our residential and school areas are 25MPH,
unless there's fencing, or the school is set very far back from the road.

Besides, how much time do you really waste now?  Isn't it just the
feeling of going slow that irritates you?

As far as more deaths occuring on other roads, are those car-person
collisions, or car-car collisions?  If they are car-person, then I'd
agree with you, the speed limit ought to be lowered.  But for car-car
collisions there is a point of diminishing returns.  Sure, you could
lower it to 30KPH, but you'd have the same number of accidents and
deaths as you have at 60KPH.

-Adam

Patrick J wrote:

>
>We have never had a fatal accident infront of our schools here so
>bearing that in mind its stupid to start setting even lower limits there
>considering we have alot of ppl getting killed on other roads.
>Why not start there ? (and what to do there is another thread :)
>
>

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2001\10\30@125705 by Harold M Hallikainen

picon face
       Speaking of radar detectors and emissions from them, this just showed
up!

Harold


> ****************************************************
>
> FCC Proposes Changes To Part 15.
> ****************************************************
>
> In a Notice of Proposed Rule Making (NPRM) released on October 15th,
the
{Quote hidden}

regulations
> place strict limits on the operation of remote control devices, and
> prohibit the transmission of data except for recognition
> codes to identify specific transmitters in a system.  A number of
> manufacturers have expressed interest in developing devices that
> transmit identification codes, supplemented with the transmission of
> some additional minimal data.
>
> The FCC has also proposed harmonization of rules covering radio
> frequency identification systems.  In response to a petition from a
> standards committee operating under the auspices of the National
Council
> for Information Technology, the Commission is seeking comments on
> whether it should harmonize its own emissions limits for RFID devices
> with the slightly less restrictive emissions limits in place in the
> European Union and Australia.
>
> A number of additional changes to the Commission's rules have also been
> proposed in this NPRM.  Comments on all of the proposed changes are due
> to the Commission 75 days from their publication in the Federal
Register
> (approximately the end of December).
>
> Readers can review the complete text of the Commission's NPRM through
> at:
>
> http://www.conformity-update.com/fcc-part15-011015.pdf .
>

FCC Rules Online at http://hallikainen.com/FccRules
Lighting control for theatre and television at http://www.dovesystems.com

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2001\10\31@125524 by Russell McMahon

picon face
> Aside from all that nit-picking, studies show that at 25MPH (pretty
> close to 30KPH) significantly fewer deaths result due to car accidents
> than at the next higher speed.  It's not a matter of 'if' someone will
> be run into, it's a matter of 'when' and how bad it's going to be.  At
> 30KPH most people live no matter how they were hit.

As I noted previously, an empirical formula that gives a rough feel for
pedestrian death rate versus impact speed is

   Death % = V^2/50            v in kph

       kph        % killed
       20         8
       25         12
       30          18
       35          24
       40          32
        45         40
       50          50
       60          70
       70          100
       >70        Overkill

I produced this formula based on published speed versus death percent
figures.
As energy in vehicle rises with V^2 this makes some intuitive sense.

Obviously SOME people will die in a 5kph collision and some will survive a
100 kph collision but ther above gives a feel for probable results.
Obviously (but not apparently to some judging from some offlist criticism I
received) this is just a guide and makes a statement about probability.

Note that this is IMPACT speed. If you are travelling at 30 kph and get to
the brakes before impact you will be going even slower and the chancesof the
pedestrian living are excellent. At even 50 kph the reaction time carries
you further, you are further away from the pedestrian when they step out
(and especially for a child will be less noticeable) and the chances both of
impact and death are MUCH higher.



           Russell McMahon

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2001\10\31@125635 by Patrick J

flavicon
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From: "M. Adam Davis"
> So you want to keep the speed limit high until it does happen?
Yes. Everything happens if you wait long enough. It havent happend
in the past 200 years, but it _might_ in the next 500, who knows...

You know there will be accidents on every single road in the world,
why not speed limit to 5 km/h everywhere ? Ill tell you why.
It all comes down to a risk assesment. You balance the pros
and cons of using a car and the danger it poses to the world.

I say that the risk at these schools here doesnt justify this new limit
judging from history (the only fact we know for sure). 'Big brother'
doesnt agree, so there we have it. Many ppl think this new limit is so
stupid that they jeopardize their drivers lic. by 'speeding' (50) there.

You could say that one dead/hurt kid is one too many. And I'd agree.
Fact are that ppl, even kids, die all over the place. Do we stop using
cars/end hunger/war/ etc etc?

I know we must do everyting to protect the children, but somehow
driving by these schools in slowmotion every day when the street is
empty and the kids have gone home annoys me.
Yes, its better survival rate to go 30 km/h if a kid would fall down from
outerspace and i'd hit it. Slim chances that will ever happen tho.

We have way too much 'big brother' mentality in this country. It
would be one thing if the limit could be adaptive: that is, actually
set to 30 km/h when it is really justified (kids around).
And 50 km/h the rest of the time. Since this cant be done I prefer the
old system that has worked fine so far: the driver decided.

As it is now we have alot of cars speeding down/up wasting fuel and
time, drivers getting annoyed (therefor more dangerous in traffc)
all day for basically no reason. Well more time to drive/snail by the
school and watch the kids sitting _inside_ the classrooms!
I have noticed that ppl now plays with their radio/CD/phone when
driving by the school... No wonder since ppl gets bored/not focused
on driving when it has come to practically a standstill. I dont think
that will benefit safety much.

I suggest put up a 3 meters high fence instead. Thats something really
safe compared to this shit speed limit moron idea. A couple of new
roadsigs or a fence, guess which is cheaper ?

> studies show that at at 25MPH significantly fewer deaths
Speed kills period. If we all drove 5 km/h all the time it would be
safer. If none drove at all, traffic would be safe.

> Besides, how much time do you really waste now?  Isn't it just the
> feeling of going slow that irritates you?
Yes, its mainly the feeling of parking in the middle of the street
when I am alone on it that I resent. Also I think I am able to
decide when to go slow. Not completely mentaly disabled yet.

Two years back they came up w yet another 'brilliant' idea.
-Hey, lets set a 90 km/h speedlimit on 110 km/h roads during wintertime!
This ofcourse in the same warm and fuzzy spirit of drivers are morons
and cant be trusted to decide when to slow down. Guess what happend ?
We now have _more_ accidents on those roads! They are now ofcourse
pussled by this, and I bet, will reason that this cant be right so we better
keep that low limit. They fail to see that irritated drivers dont drive safely.

Theres much more to traffic safety than a low speedlimit.
Drivers want to drive in a, as they feel, justified speed. If someone sets
a limit that the public doesnt feel is the proper one you will get irritation.
The environment surrounding the roads/streets must be forgiving
in that sense it allows for someone to drive off the road and survive.
Keep meeting traffic separated, preferably with distance between the
lanes and/or concret walls as our highways has.
Actions like that costs and investing in infrastructure like roads isnt
'politically correct' here now so they go for cheap second rate solutions.

</my third and final posting on this OT-OT thread>
(feel free not to reply since I have a he**uva time to resist replying ;-)
/PJ

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2001\10\31@125936 by Bob Blick

face
flavicon
face
> > Having had a child run out of a gateway into the side of my car while I was
> > doing 20mph, I cannot sympathise with your sentiments. You can bet your
> > bottom dollar that one day someone is going to do this to you right when you
> > least expect it. It happened to me in a deserted street, so just because you
> > see no-one around the school outside setdown and pickup hours means
> > nothing

That's why we need those kids to wear radar "drones" so it sets off our
radar detectors and we can slow down and watch for them.

Bob "Full circle OT thread" Blick

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2001\10\31@133743 by Dale Botkin

flavicon
face
On Tue, 30 Oct 2001, Bob Blick wrote:

> That's why we need those kids to wear radar "drones" so it sets off our
> radar detectors and we can slow down and watch for them.
>
> Bob "Full circle OT thread" Blick

<chuckle>...   Masterful, Bob, simply masterful!  8-D

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2001\10\31@220252 by Russell McMahon

picon face
> > > Having had a child run out of a gateway into the side of my car while
I was
> > > doing 20mph, I cannot sympathise with your sentiments. You can bet
your
> > > bottom dollar that one day someone is going to do this to you right
when you
> > > least expect it. It happened to me in a deserted street, so just
because you
> > > see no-one around the school outside setdown and pickup hours means
> > > nothing
>
> That's why we need those kids to wear radar "drones" so it sets off our
> radar detectors and we can slow down and watch for them.


And, as an added bonus, if they wore them to & from school as well, they'd
help make the roads safer for all the rest of us as well. At least until the
"cry wolf" syndrome set in. Typical arms race.



       R "450 degrees" M

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'[OT]: how does a radar detector work?'
2001\11\01@052953 by Gerhard Fiedler
flavicon
face
At 01:59 10/31/2001 +0100, Patrick J wrote:
>Fact are that ppl, even kids, die all over the place. Do we stop using
>cars/end hunger/war/ etc etc?

We don't, obviously, but maybe we could think about doing some of this
differently? :)

--------------------------------------

>Since this cant be done I prefer the old system that has worked fine so
>far: the driver decided.

>Speed kills period. If we all drove 5 km/h all the time it would be safer.
>If none drove at all, traffic would be safe.

>Also I think I am able to decide when to go slow.

Basically, I agree with all of this. But to me, this sounds as if driving
at a speed higher than 5 km/h would mean that we necessarily and
consciously accept the risk of killing someone (with which I also agree).
If this were anything else besides driving a car, a resulting death of such
a risk would be handled as manslaughter -- but since it happened whie
driving, it's considered an "accident."

I never really understood this difference. To me, personal responsibility
is this... I guess if it were handled as manslaughter, we indeed would not
need any speed limits at all. You've got to look at speed limits in this
way: they protect you from this responsibility. No speed limits means full
responsibility... and full responsibility means that when you cause the
death of someone, you are responsible for it. There are not many drivers
around who actually would accept this responsibility.

--------------------------------------

It's funny that mostly drivers of motor vehicles complain about excess of
regulations -- considering the fact that all these regulations are only
necessary in order to provide a relatively free flow of traffic for motor
vehicles. If we had no regulations, everybody could and would pretty much
do on the street what (s)he pleases (after all, it is public ground), as it
mostly used to be before motor vehicles, without much danger and without
disturbing much. After the arrival of motor vehicles, the drivers of such
found it necessary to regulate what happens on the street and what not.
This is the origin of our current traffic laws. (Well, maybe not the origin
-- I'm sure there have been regulations of some sort in some places before
motor vehicles --, but you get the idea... :)

In any case, the point is that the regulations in their totality serve
primarily the goal to keep the vehicle traffic flowing. Imagine no
regulations... you literally could not go more than 5 km/h, if you could go
at all.

ge

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2001\11\01@054924 by David VanHorn

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>
>I never really understood this difference. To me, personal responsibility
>is this... I guess if it were handled as manslaughter, we indeed would not
>need any speed limits at all. You've got to look at speed limits in this
>way: they protect you from this responsibility. No speed limits means full
>responsibility... and full responsibility means that when you cause the
>death of someone, you are responsible for it. There are not many drivers
>around who actually would accept this responsibility.

There are, however, quite a number who would drive without actually
thinking about it, and I won't be in much of a state to complain, after
being mashed into a red smear.

>In any case, the point is that the regulations in their totality serve
>primarily the goal to keep the vehicle traffic flowing. Imagine no
>regulations... you literally could not go more than 5 km/h, if you could go
>at all.

You've never been in a taxi in Taiwan.. :)

The only rule they seem to take to heart is "try not to hit things".


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2001\11\01@075552 by Gerhard Fiedler

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At 05:40 10/31/2001 -0500, David VanHorn wrote:
>>No speed limits means full
>>responsibility... and full responsibility means that when you cause the
>>death of someone, you are responsible for it. There are not many drivers
>>around who actually would accept this responsibility.
>
>There are, however, quite a number who would drive without actually
>thinking about it, and I won't be in much of a state to complain, after
>being mashed into a red smear.

Of course, there would be a few start-up "cases," so to speak an
initialization phase until the system begins regulating itself :)  But
after people realize that they will go to a manslaughter trial and probably
will go to jail for a few years for this, I bet my hat (*) that this would
be more effective than speeding tickets.


>You've never been in a taxi in Taiwan.. :)
>
>The only rule they seem to take to heart is "try not to hit things".

I've been in similar situations, even though not in Taiwan :)   But I
didn't mean no laws at all, I meant just no traffic laws, with all the rest
of the US laws (and their enforcement) in place. Places that are like you
describe Taiwan usually have a general lack of appropriate laws and law
enforcement.

ge

(*) I don't wear a hat, generally, but this may not be relevant :)

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2001\11\01@104337 by Gerhard Fiedler

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At 01:59 10/31/2001 +0100, Patrick J wrote:
>Fact are that ppl, even kids, die all over the place. Do we stop using
>cars/end hunger/war/ etc etc?

We don't, obviously, but maybe we could think about doing some of this
differently? :)

--------------------------------------

>Since this cant be done I prefer the old system that has worked fine so
>far: the driver decided.

>Speed kills period. If we all drove 5 km/h all the time it would be safer.
>If none drove at all, traffic would be safe.

>Also I think I am able to decide when to go slow.

Basically, I agree with all of this. But to me, this sounds as if driving
at a speed higher than 5 km/h would mean that we necessarily and
consciously accept the risk of killing someone (with which I also agree).
If this were anything else besides driving a car, a resulting death of such
a risk would be handled as manslaughter -- but since it happened whie
driving, it's considered an "accident."

I never really understood this difference. To me, personal responsibility
is this... I guess if it were handled as manslaughter, we indeed would not
need any speed limits at all. You've got to look at speed limits in this
way: they protect you from this responsibility. No speed limits means full
responsibility... and full responsibility means that when you cause the
death of someone, you are responsible for it. There are not many drivers
around who actually would accept this responsibility.

--------------------------------------

It's funny that mostly drivers of motor vehicles complain about excess of
regulations -- considering the fact that all these regulations are only
necessary in order to provide a relative free flow of traffic for motor
vehicles. If we had no regulations, everybody could and would pretty much
do on the street what (s)he pleases (after all, it is public ground), as it
mostly used to be before motor vehicles, without much danger and without
disturbing much. After the arrival of motor vehicles, the drivers of such
found it necessary to regulate what happens on the street and what not.
This is the origin of our current traffic laws. (Well, maybe not the origin
-- I'm sure there have been regulations of some sort in some places before
motor vehicles --, but you get the idea... :)

In any case, the point is that the regulations in their totality serve
primarily the goal to keep the vehicle traffic flowing. Imagine no
regulations... you literally could not go more than 5 km/h, if you could go
at all.

ge

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2001\11\01@181516 by steve

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> You've never been in a taxi in Taiwan.. :)

ROFL.

I've jumped out of planes, done the white water rafting thing, drive a
hot-rod, etc - but I always recall my ride in the front seat of a taxi in
Taipei as one of the most terrifying moments of my life.

> The only rule they seem to take to heart is "try not to hit things".

I think that is "try not to hit concrete things". Things on scooters
don't seem to count. :-)

Steve.



======================================================
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TLA Microsystems Ltd         Microcontroller Specialists
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2001\11\01@182753 by David VanHorn

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At 12:07 PM 11/2/01 +1200, Steve Baldwin wrote:
> > You've never been in a taxi in Taiwan.. :)
>
>ROFL.
>
>I've jumped out of planes, done the white water rafting thing, drive a
>hot-rod, etc - but I always recall my ride in the front seat of a taxi in
>Taipei as one of the most terrifying moments of my life.
>
> > The only rule they seem to take to heart is "try not to hit things".
>
>I think that is "try not to hit concrete things". Things on scooters
>don't seem to count. :-)


The most I ever saw on a scooter was seven.
I heard of nine, but didn't see it personally.
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2001\11\01@195207 by Patrick J

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> >Speed kills period. If we all drove 5 km/h all the time it would be safer.
> >If none drove at all, traffic would be safe.

> Basically, I agree with all of this. But to me, this sounds as if driving
> at a speed higher than 5 km/h would mean that we necessarily and
> consciously accept the risk of killing someone (with which I also agree).

this is exactly what i meant, and yes we do. (ppl seldom put it in words tho)

> need any speed limits at all. You've got to look at speed limits in this
> way: they protect you from this responsibility. No speed limits means full
> responsibility... and full responsibility means that when you cause the
> death of someone, you are responsible for it. There are not many drivers
> around who actually would accept this responsibility.

Interesting point of view !
Ponder this: In Germany they have today _no_ speedlimit on parts of their roads.
Always an eXception, isn't there? :-)

/PJ

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2001\11\01@211103 by Craig R. Autio

flavicon
face
Of course..............everyone wants to know "for educational purposes
only"................

I am familiar with the VG-2 Gun and how to detect it and can guess what the
Stalcar is doing but would like to confirm.

Craig


Subject: Re: [OT]: how does a radar detector work?


> Lessee - is this poacher turned gamekeeper turned poacher turned ..... ??
or
> what.
>
> Of course, you only want this information for legitimate non-directed
> scientific research, dont you ? :-)
>       Russell McMahon

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2001\11\01@222652 by Russell McMahon

picon face
> > >Speed kills period. If we all drove 5 km/h all the time it would be
safer.
> > >If none drove at all, traffic would be safe.
>
> > Basically, I agree with all of this. But to me, this sounds as if
driving
> > at a speed higher than 5 km/h would mean that we necessarily and
> > consciously accept the risk of killing someone (with which I also
agree).
>
> this is exactly what i meant, and yes we do. (ppl seldom put it in words
tho)
>
> > need any speed limits at all. You've got to look at speed limits in this
> > way: they protect you from this responsibility. No speed limits means
full
> > responsibility... and full responsibility means that when you cause the
> > death of someone, you are responsible for it. There are not many drivers
> > around who actually would accept this responsibility.

And do note, under this system the charge would not necessarily be
manslaughter. Murder is a perfectly reasonable potential charge in such
cases. And an "enlightened" jury may well decide that a death caused by
driving at 90 kph past a school constitutes murder in much the same way that
death due to firing a .45 "randomly" in a crowded shopping centre would.

> Interesting point of view !
> Ponder this: In Germany they have today _no_ speedlimit on parts of their
roads.
> Always an eXception, isn't there? :-)

And as often, it's the one that proves the rule. This is AFAIK only on
Autobahns whose quality for such purposes is high. These roads are built
with the express purpose of allowing very high speed travel in safety. The
speed limit in this case still exists and is set by negotiation between
Governments and the vehicle manufacturers with a "voluntary" top speed of
?350 kph on "supercars". I suspect that Germany may have and enforce some
rather enlightened speed limits in other areas.



       RM

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2001\11\02@065412 by Russell McMahon

picon face
> > > You've never been in a taxi in Taiwan.. :)
> >
> >ROFL.
> >
> >I've jumped out of planes, done the white water rafting thing, drive a
> >hot-rod, etc - but I always recall my ride in the front seat of a taxi in
> >Taipei as one of the most terrifying moments of my life.
> >
> > > The only rule they seem to take to heart is "try not to hit things".
> >
> >I think that is "try not to hit concrete things". Things on scooters
> >don't seem to count. :-)

I spent a hectic week with 4 or so front seat passenger rides per day in
various private cars.
Most unnerving. BUT very very few accidents considering. No real care about
side of street in side streets until vehicles almost met and then a quick
hop into place while passing.

At major intersections (traffic lights and 5 or 6 roads intersecting and
busy traffic) a fair % of motor scooters would transit the intersection
entirely on the wrong side of the road. No accidents seen there!

I'm told that they find OUR driving behaviour unpredictable and dangerous.
Certainly, if you canme to NZ and drove like that you would die within
minutes as others would not expect it. When the rule appears to be "I'll
look after myself and aim to pass you on the right hand side of the road
unless I can get away with using the lefthand side" then it all seems to
work very well.

In a car, at ANY time of the day or night you have at least 5 scooters
behind you, 3 in front of you and two passing, one on each side :-)

> The most I ever saw on a scooter was seven.
> I heard of nine, but didn't see it personally.

I saw what appeared to be 5.



       Russell McMahon

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2001\11\02@153708 by steve

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> At major intersections (traffic lights and 5 or 6 roads intersecting
> and busy traffic) a fair % of motor scooters would transit the
> intersection entirely on the wrong side of the road. No accidents seen
> there!

You couldn't see them because of all the smoke.
One of my lasting impressions of the place was looking down on
an intersection when the lights turn red. Hundreds of scooters
appear and all sit there going "nyyyyynnnng nyng nyng", slowly
filling the intersection with a grey haze. When the light goes green
there's a long "nnnnnyyyyyynnnnngggg" noise and the whole
intersection disappears in a blue-grey cloud.

> I'm told that they find OUR driving behaviour unpredictable and
> dangerous.

I've never been able to equate the stereotypical "Asian driver" here
with a taxi experience in Taiwan. They are complete opposites.

Steve.

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Steve Baldwin                Electronic Product Design
TLA Microsystems Ltd         Microcontroller Specialists
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2001\11\02@160348 by David VanHorn

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>
>You couldn't see them because of all the smoke.
>One of my lasting impressions of the place was looking down on
>an intersection when the lights turn red. Hundreds of scooters
>appear and all sit there going "nyyyyynnnng nyng nyng", slowly
>filling the intersection with a grey haze. When the light goes green
>there's a long "nnnnnyyyyyynnnnngggg" noise and the whole
>intersection disappears in a blue-grey cloud.

I remember many visits where I could only see Chen Ching lake on the
weekends, even though I could always throw a rock into it from our apartment.

The major accidents I saw usually involved a logging truck, carrying many
tons of logs with only one chain (or even one rope!) to secure the
load.  Snap-smash, oops.

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2001\11\03@080542 by Gerhard Fiedler

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At 16:24 11/02/2001 +1300, Russell McMahon wrote:
> > Ponder this: In Germany they have today _no_ speedlimit on parts of their
>roads.
> > Always an eXception, isn't there? :-)
>
>I suspect that Germany may have and enforce some
>rather enlightened speed limits in other areas.

Last I heard was that while there is no general limit (yet) for the German
Autobahns, there are very few of them left without a specific speed limit
on most of their parts. These are usually around 100..130 km/h.

ge

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2001\11\03@081613 by Gerhard Fiedler

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At 01:50 11/02/2001 +0100, Patrick J wrote:
>this is exactly what i meant, and yes we do. (ppl seldom put it in words tho)

good that we agree... :)  and i think it helps putting it in words, every
now and then. helps keep the perspective of things.

ge

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2001\11\03@165254 by Mik Juneau Kim

picon face
God (in any denomination) gave us the speed limit. What's the point in having an artificial one? Personally, I iike the speed limit given by god and try not to violate it, although I hear some physics folks are trying.

I would like to see a sign SPEED LIMIT 186000 mps

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2001\11\04@031349 by Russell McMahon

picon face
God (in any denomination) gave us the speed limit. What's the point in
having an artificial one? Personally, I iike the speed limit given by god
and try not to violate it, although I hear some physics folks are trying.

I would like to see a sign
SPEED LIMIT 186000 mps


Ok we seem to have got tot he stage in this thread where I can use these
lines :-)

Speed kills.
Absolute speed kills absolutely.



       RM

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2001\11\04@083108 by Roman Black

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Russell McMahon wrote:

> I would like to see a sign
> SPEED LIMIT 186000 mps
>
> Ok we seem to have got tot he stage in this thread where I can use these
> lines :-)
>
> Speed kills.
> Absolute speed kills absolutely.


Russell, i'm HORRIFIED to see you propagating
what is obviously a total lie. This is not
scientific fact! This is a propaganda buzzphrase
designed to brainwash the stupid masses.

Speed DOES NOT kill. Ever. You can get in a
737 plane and do 800 kph, in perfect safety.
You can do 20,000 kph on the space shuttle.
You can do 315 kph on a French train every day
to work, in perfect safety. You can get in a
Ferrari, (or my motorbike) and do 200kph
on any reasonable road in perfect safety.

Crashing kills. Accidents kill. Bad driving
kills. Speed does not.

I respect you greatly for your intellect and
sensible attitude in your other posts, please
don't blow it here, on a scientific or social
level. :o)

I have paid good money and invested a huge
amount of hours to become a skilled driver on
the street or the racetrack, and I am the person
who decides the SAFE speed that I need to
travel at. Stupidity kills. Lack of skill kills.
Speed? It's like electricity, it should be
handled by trained, mature, competent people,
not traffic cops or media marketers.
-Roman

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2001\11\04@114147 by Jim

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face
 "> > Speed kills.
  > > Absolute speed kills absolutely."

What's the effective rotational speed on the surface
of the Earth?

I rest my case ...

Jim



{Original Message removed}

2001\11\04@185158 by Russell McMahon

picon face
> Russell McMahon wrote:
> > Speed kills.
> > Absolute speed kills absolutely.

> Russell, i'm HORRIFIED to see you propagating
> what is obviously a total lie. This is not
> scientific fact! This is a propaganda buzzphrase
> designed to brainwash the stupid masses.

Well, assuming that it was seen that the above was a joke (and a pun), and
entering into the spirit of Roman's response (t least, I hope I've got it
right) ...

- Absolute speed is, as was noted by the prior poster, about 186,000 miles
per second = "the speed of light".
- Only light can travel at the speed of light. Anything with mass can NEVER
travel at the speed of light as to do so would require infinite energy and
result in infinite mass.
- Anything which has zero res t mass (eg all Photons and POSSIBLY Neutrino's
(which MAY have negative rest mass ;-) ) MUST always travel at the speed of
light.
- At the speed of light time ceases to exist. Everything happens
instantaneously (or not at all). Everything that has happened, is happening,
or ever will happen, happens NOW or not at all (depending on your
perspective). Nothing has velocity or acceleration (as these are a function
of time).

So, to summarise:

   Anything which travels at absolute speed must be massless, and not move
in any way.
   It clearly CANNOT be alive. Its absolutely dead.
   If it ever was alive then its not now so achieving absolute speed must
have killed it.

   Therefore, absolute speed kills absolutely

   QED :-)


           RM

______________________________________________________
______________________________________________________


Russell McMahon wrote:

> I would like to see a sign
> SPEED LIMIT 186000 mps
>
> Ok we seem to have got tot he stage in this thread where I can use these
> lines :-)
>
> Speed kills.
> Absolute speed kills absolutely.


Russell, i'm HORRIFIED to see you propagating
what is obviously a total lie. This is not
scientific fact! This is a propaganda buzzphrase
designed to brainwash the stupid masses.

Speed DOES NOT kill. Ever. You can get in a
737 plane and do 800 kph, in perfect safety.
You can do 20,000 kph on the space shuttle.
You can do 315 kph on a French train every day
to work, in perfect safety. You can get in a
Ferrari, (or my motorbike) and do 200kph
on any reasonable road in perfect safety.

Crashing kills. Accidents kill. Bad driving
kills. Speed does not.

I respect you greatly for your intellect and
sensible attitude in your other posts, please
don't blow it here, on a scientific or social
level. :o)

I have paid good money and invested a huge
amount of hours to become a skilled driver on
the street or the racetrack, and I am the person
who decides the SAFE speed that I need to
travel at. Stupidity kills. Lack of skill kills.
Speed? It's like electricity, it should be
handled by trained, mature, competent people,
not traffic cops or media marketers.
-Roman

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2001\11\04@191518 by John Ferrell

flavicon
face
For your information:
While the constant known as the speed of light has served us well in the
past, it may not be as "constant" as we have believed. There is credible
work that challenges the accepted figure as a limit.

I would explain it if I understood it. Perhaps there is list lurker who can
offer more information.

John Ferrell
6241 Phillippi Rd
Julian NC 27283
Phone: (336)685-9606
Dixie Competition Products
NSRCA 479 AMA 4190  W8CCW
"My Competition is Not My Enemy"



{Original Message removed}

2001\11\04@203440 by Russell McMahon

picon face
In a more serious vein -



> Russell McMahon wrote:

> > Speed kills.
> > Absolute speed kills absolutely.

That was a joke (as in "Power corrupts, absolute power ..." ) , but ...

I'll move this up to the top -

Roman said -
> I respect you greatly for your intellect and
> sensible attitude in your other posts, please
> don't blow it here, on a scientific or social
> level. :o)

The feelings are mutual. But respect needs to be earned or lost on each
independent "battlefield". Not all respect is transferable :-)
Hopefully you will not find me lacking in scientific approach. Whether in
social approach is for each to decide.
I'm sure you also are prepared to demonstrate scientific and social
"sensibleness" in this discussion.

> Speed DOES NOT kill. Ever.

Similar but not identical to the US "guns don't kill people, people kill
people" line.

> You can get in a
> 737 plane and do 800 kph, in perfect safety.
> You can do 20,000 kph on the space shuttle.

> You can do 315 kph on a French train every day
> to work, in perfect safety.

Most days anyway - I saw a picture of one lying on its side smoking gently
to itself a few days ago after a high speed derailment, but it was well
enough designed that nobody died. (I have managed a mere 230 kph in a
Japanese "Shinkansen".)

> You can get in a
> Ferrari, (or my motorbike) and do 200kph
> on any reasonable road in perfect safety.
> Crashing kills. Accidents kill. Bad driving
> kills. Speed does not.

No. None of these kill any more, or less, than speed does. Killing is a
function of all its components. I can bad-drive all day long in my garage
with the brakes on and I'm most unlikely to die (except, maybe, from CO
poisoning). I can bad-drive on the roads at 10 kph and I'm less likely to
kill than an averagely competent driver on a "reasonable" road at 200 kph.
But if I bad-drive at 100 kph I MAY be more liable to kill than an averagely
competent driver at 200 kph. And maybe not. Speed is undeniably a function
in the equation along with all the rest. (Even though people deny it :-) )
If you had to produce a formula which predicted probably outcomes of given
road events then if your formula demanded that speed be left out for PC
reasons the formula would be an inadequate one unless you then included
speed in some other indirect manner. Sure, speed alone doesn't kill - but
ultimately it's the collision energy that kills, and speed is a physical
factor in this. Only if your driving can ensure no collisions ever (and it
can't) can you remove speed from consideration.

As you well know, one reason that YOU cannot remove collisions from
consideration is that "I" am also driving / playing / running on the road.
No matter how competent YOU are I can combat your competence with my
incompetence, or my inexperience or my youthfulness or my inability to fully
predict how you in your great and (literally) death defying competence are
going to appear into my world. If I as a child run into your path because
your 200 kph motorcycle seemed so small and distant that it did not seem a
threat then all bets may be off. And so on through a few zillion other
potential examples ....

> I have paid good money and invested a huge
> amount of hours to become a skilled driver on
> the street or the racetrack, and I am the person
> who decides the SAFE speed that I need to
> travel at.

On the race track - certainly.
On the street - no.
Why? - see below.

> Stupidity kills. Lack of skill kills.
> Speed? It's like electricity, it should be
> handled by trained, mature, competent people,
> not traffic cops or media marketers.

I'll agree with this analogy as far as it goes.
Public road driving is governed by social contract. As has been well argued
over centuries (indeed, millenia) your freedoms at least begin to be limited
when they impact and affect other people's freedoms. A majority of your
countymen (and mine) have chosen to live in a Democracy and not in an
Anarchy. You could all, should you wish, choose at the very next election to
live in an Anarchy. "We of the Decomcratic Anarchists, when we win the next
election, promise to dismantle ALL state intervention in your lives, all
taxes, all speed limits (and any other limits) all .... . If we fail to
deliver on our promise, feel free to kill us, who's going to stop you ?) ).

In a more realistic context, there are many people present in our society of
varying competencies and expectations. They (almost) all have SOME DEGREE of
right to use the roads for transport and leisure. The rights of ALL must be
balanced in setting "limits on reasonable freedoms" to meet the desires of
the majority in a way which is acceptable to the majority. Anyone who
chooses may travel below the speed limits if they choose to do so. By so
doing they MAY improve their safety levels. They also MAY decrease their
safety levels due to interactions with other drivers. On our country roads
(nice and winding in many places) I often travel at times BELOW the posted
speed limits on some corners if my wife is in the car. If I am driving by
myself I almost always drive AT the speed limit - to the maximum extent
reasonably possible in my judgement given conditions and vehicle and my
capabilities. I enjoy driving fast. So what?

There are speeds which are NEVER safe to drive at because the uncertainties
introduced by people other than the super competent driver introduce risks
which are unacceptable to people other than the super-competent driver.
NOBODY (not even Roman) could safely drive down my residential street at 200
kph. In fact, nobody (not even Roman) could safely drive down my residential
street at 100 kph. (It has one 30 degree dog-leg bend and is otherwise
straight). In both cases the risks to others exceeds the social contract
risks agreed to by all who accept a motor drivers licence. It WOULD, I
think, be possible for someone like Roman to "safely" drive down my street
at 70 to 80 kph as long as they actively and intentionally applied their
immense and impressive reaction times and experience of high speed driving
to decrease their level of danger down to that imposed by Joe average driver
at 50 kph, which is where the social-contract risk is set. Above that speed
the ball, the child, the dog, the man backing out, the teenage learner
driver and more impose a level of risk wich is above that which we all have
mutually agreed to accept.

IF we decided to test each person individually we could assign the Roman's
special "can do 70 kph in residential streets and 235 kph on the open road"
status. And some "can do 40 kph max anyuwhere" status.  This however poses
extreme problems. If SOME can legally traverse my street at 70 kph be
utterly assured than many who are neither entitled to or copetently able to
will also choose to do so. The social contract will be violently abrogated
by those who are incompetent. We could then choose to require bright
identification of vehicle and/or driver or electronic tagging or electronic
vehicle enablement to match allowable speeds to drivers' entitlements and
capabilities or ... . This all gets pretty unmanageable & unacceptable
politically pretty quickly. Even if we did get a workable acceptable system
we would then have the situation where nominally equivalent vehicles were
allowed (indedd compelled) to travel ay widely disparate speeds in the same
circumstance. Some would be allowed to overtake and not others. Mayhem would
ensue. Certyainly in urban areas, in any given situation, a constant speed
limit for all is highly desirable. In "open road" situations more
flexibility may be possible without total chaos ensuing. But only "may".
Adherence to "social contract" by "1st, 2nd, and 3rd grade drivers"  is sure
to test male testosterone driven behaviour and relate to all and sundry
seeking to behave as if they were all Roman class drivers.

An interesting "experiment" is to ask a group of youing males how they rate
their driving abilities compared to the norm. Just about all, I'm told, will
rate themselves 'above average". As indeed do I :-). And those most liable
to do this (males aged 16 to 24 years old) are those most disproportionately
represented in the died while * driving statistics.
* - (or actually, as speed is not what kills, "died instantaneously after
having been driving" :-) )

Now, Roman claims to be in an elite group of drivers who can safely drive at
high speed and who is mature enough top determine their own limits. I
suspect, based on the little that I know of him, that  he probably is in
most circumstances (but certainly not in all circumstances). Should I be
happy to let everyone else who claims similar capability make their own
decisions? Should I be happy with any number of people whjo think, like
Roman that

   > trained, mature, competent people,
   > not traffic cops or media marketers.

when they themselves decide the level of training, maturity and competence
is required?
If Roman's children were the one's at risk I'm sure that he would not agree
with this (and I'm sure that he doesn't) but in the absence of a system
which allows this to happen with a formal methodology what the argument
really turns into is 'I can drive at whatever sped I like because I know my
capabilities". The two ideas are, of course, worlds apart but most would say
the former and mean the latter.

In an imperfect world the freedoms of the more capable are limited to some
extent by the extent to which they may encroach on the freedoms of the less
capable. In most places the excessively competent are still free to
demonstrate their safe superiority and risk the consequences. The truly more
competent (like Roman) are less liable to be "caught" than the least
deserving and to that extent they somewhat make their point. They make it
best by living to a ripe old age (and Roman is no "Spring Chicken" :-) )
without having killed or damaged either themselves or any children or others
along the way.

If you (whoever you are) manages to transit my highways at an occasional 200
kph without coming to anyone's notice, and without causing anyone to have
had to take defensive action or to have been in any risk of their life or
safety, then you have done moderately well. This judgement can only be made
retrospectively and after the termination of all such activities. If however
you are involved in a fatal collision with ANY other road user under such
conditions then I would hope you would be happy to defend vigorous charges
of manslaughter and perhaps of murder. In the event of your not surviving
the event yourself (which is entirely likely) I would hope your estate would
need to be prepared and able to remit the appropriate penalty for an
innocent life taken should the courts so decide. (And what is the
appropriate penalty for the death of a child?) Similar provisions would need
to apply to non-fatal accidents with other road users. If any of these
expectations are felt to be unreasonable then the right to exercise such
excessive speeds is equally non-existent.



regards



               Russell McMahon



PS1    For an impressive but also poignant record of one who didn't fully
manage to manage the challenge see

   http://www.dynopower.freeserve.co.uk/nitrous_oxide/

.


PS 2

A brief comment on Roman's electricity analogy: We expect our mains voltages
to be within a certain range. We don't expect 11 kV to appear at a wall
outlet most days. Very occasionally it does ! There are regulations as to
who can connect what and how installations are certified. There are
standards to be met for equipment and work practices. There are examinations
and tests for competency. There are graded areas for involvement - these are
similar to classes of licence for car/motorcycle.bus/taxi/heavy vehicle. The
amateur may very largely transgress these boundaries as long as they don't
place the lives of others at risk. They may built devices laser power
supplies and Tesla coils without formal licences. In most countries at
least, once they wished to pursue such activities commercially they would be
required to meet regulations I think the road-user/electricity analog is a
reasonable if imperfect one.

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2001\11\04@203506 by Russell McMahon

picon face
>   "> > Speed kills.
>    > > Absolute speed kills absolutely."
>
> What's the effective rotational speed on the surface
> of the Earth?
>
> I rest my case ...


Relative to what ? :-)
& what's in your case?

Relative to the earth's orbital plane it's about 1000 mph / 1600 kph.
Well below light speed (fortunately).



           RM

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2001\11\04@215011 by steve

flavicon
face
> While the constant known as the speed of light has served us well in
> the past, it may not be as "constant" as we have believed. There is
> credible work that challenges the accepted figure as a limit.

I have no idea about this "credible work", but as a layman in the
subject, the speed of light does seem to make the assumption that
time is constant. Is it ?
Wrap your mind around that one. :-)

Steve.


======================================================
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TLA Microsystems Ltd         Microcontroller Specialists
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Auckland, New Zealand        ph  +64 9 820-2221
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2001\11\04@215308 by Jim

flavicon
face
BUT we're all doing it and eventually we all die too.

Actually, that seems to go in support of your original
premise/argument/quote <grin> ...

Jim

{Original Message removed}

2001\11\04@220202 by David VanHorn

flavicon
face
At 03:44 PM 11/5/01 +1200, Steve Baldwin wrote:
> > While the constant known as the speed of light has served us well in
> > the past, it may not be as "constant" as we have believed. There is
> > credible work that challenges the accepted figure as a limit.
>
>I have no idea about this "credible work", but as a layman in the
>subject, the speed of light does seem to make the assumption that
>time is constant. Is it ?
>Wrap your mind around that one. :-)

Discovery channel this summer had a show on cosmology, near the end of the
show, they discussed some evidence that the fine structure constant may not
be (constant).

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2001\11\05@014624 by Russell McMahon

picon face
> At 03:44 PM 11/5/01 +1200, Steve Baldwin wrote:
> > > While the constant known as the speed of light has served us well in
> > > the past, it may not be as "constant" as we have believed. There is
> > > credible work that challenges the accepted figure as a limit.
> >
> >I have no idea about this "credible work", but as a layman in the
> >subject, the speed of light does seem to make the assumption that
> >time is constant. Is it ?
> >Wrap your mind around that one. :-)
>
> Discovery channel this summer had a show on cosmology, near the end of the
> show, they discussed some evidence that the fine structure constant may
not
> be (constant).

Plotting early measurements and known error ranges of the speed of light
suggest that it has been falling at a decreasing rate over the last
millennia and that the curve is now "flattening out" to the stage that we
can consider it essentially constant. There are other interpretations of the
same data.

There is no known reason for the speed to BE constant or to have a
particular value.
There is not even, AFAIK, a REASON for it to have the same value in distant
localities although it would certainly pervert our ideas of the laws of
Physics if it did and require a few cosmological texts to be revised..

There are a surprising number of physical parameters which are inter-related
in such a manner that usual measurements which depend on some of them will
always reveal the same value for others even if there has been a change, due
to their inter-related nature. The speed of light is one such.

A simplistic analogy is attempting to measure the oscillator frequency of a
digital frequency meter using the meter. If a 10 MHz crystal is used then it
will appear produce a 10.000000 MHz signal no matter what its TRUE frequency
is, as the functioning of the meter depends on the initial assumption of
correct crystal frequency.



   Russell McMahon

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2001\11\05@045629 by Mik Juneau Kim

picon face
Ummm. I always thought that stopping (rapid deceleration) kills, not the
speed??? Knowing that Dihydrogen-Oxide is a very potent "drug" (I'm an
addict) and "stopping" kills, I propose we start a petition to ban these two
things from the face of the earth.

> > > Speed kills.
> > > Absolute speed kills absolutely.

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2001\11\05@050238 by Mik Juneau Kim

picon face
I slow down the speed of light all the time. I have special device that
attaches to my earlobe and bridge of my nose. As the light enters the
device, it slows down drastically just before it enters my eyes. It's pretty
cool; I can see things that are too far away to see with my naked eyes.  ;-)

{Original Message removed}

2001\11\05@052535 by Alan B. Pearce

face picon face
> Speed kills.
> Absolute speed kills absolutely.

And of course we should remind ourselves that food consumption causes a 100%
mortality rate ;)

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2001\11\05@053620 by Gerhard Fiedler

flavicon
face
At 00:14 11/05/2001 +1100, Roman Black wrote:
>Russell, i'm HORRIFIED to see you propagating what is obviously a total
>lie. This is not scientific fact! This is a propaganda buzzphrase designed
>to brainwash the stupid masses.

He wrote it with a ":-)".

If you need a more serious approach, please consider the previous
discussion of this subject (and also in the related thread).

>Crashing kills. Accidents kill. Bad driving kills. Speed does not.

Bad driving at 5 km/h is much less likely to kill than bad driving at 150
km/h. I guess this can be considered a scientific fact. If not scientific,
then common sense. If not common sense, then we may have to see whether we
have a consensus on "sense" :)

It seems also to be a fact that we can't stop bad (or irresponsible)
drivers from driving. Never seen a place where there weren't bad drivers on
the road.

Now combine these two facts, and you actually may get to a logical chain...

You have a set comprised of representative driver skills (to represent the
current state on the roads). You run this set through a transformation that
applies the probability of deadly accidents at the different speeds to the
driver skills in the set. I guess you'll have enough mathematic background
to guess the outcome -- and the relation between deaths and speed in the
outcome.

This is rather statistical and does not apply to a single individual, but
deaths on roads unluckily _are_ a statistical fact rather than individual
occurences. They are frequent enough to be handled quite well with
statistical methods.

>I have paid good money and invested a huge amount of hours to become a
>skilled driver on the street or the racetrack, and I am the person who
>decides the SAFE speed that I need to travel at. Stupidity kills. Lack of
>skill kills. Speed? It's like electricity, it should be
>handled by trained, mature, competent people, not traffic cops or media
>marketers.

I respect your training efforts and agree that more people should do this.
I would be all for self responsibility, if you actually stood up for your
words. But so far I haven't seen a driver who would be willing to assume
full responsibility for every dead he may cause. After you, accidentally,
killed someone (maybe less likely than for any other driver, but still
possible), you'll probably use all the protection the traffic laws give you
to avoid being jailed for manslaughter or murder, won't you? If it did
happen in other circumstances, you would be jailed for manslaughter or
murder, but not while driving a car. This is not what I call
"responsibility." And this lack of responsibility is intimately linked to
the existence of speed restrictions.

ge

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2001\11\05@063008 by artstar

flavicon
face
Ok then, here is a simple solution to all this arguing about speed, and
driver responsibility, etc.

I agree with the idea that it's driver skill that kills and not speed
alone. The best of drivers can determine what is an appropriate speed
for a given place under the given conditions.

However, many people disagree, much like you are. Many a comment is made
about responsibility and "social contract" etc etc.

So to which effect, it's an endless argument which I end with "I'll
continue to drive with the intention to kill, as you so see it. Be sure
to clear a path for me before I clear you out of it".

3#-)

[End of my contribution to the topic]

Adios,
LarZ

---------------  TAMA - The Strongest Name in Drums  ---------------

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2001\11\05@070132 by Martin Hill

picon face
This just isn't true!!  Although it is true that all people who eat will do,
therefore there is a correlation between the two, a correlation DOES NOT
prove cause and effect.

And on the other point.  Can you have absolute speed?  I thought it was
relative.

Martin

{Original Message removed}

2001\11\05@091111 by Gerhard Fiedler

flavicon
face
At 11:55 11/05/2001 +0000, Martin Hill wrote:
>This just isn't true!!  Although it is true that all people who eat will do,
>therefore there is a correlation between the two, a correlation DOES NOT
>prove cause and effect.

I have a ("scientific" :) suggestion to clarify once and for all whether
speed is a crucial factor in traffic injuries:

- Take a common car.
- Equip it with an exact speed control (easy to do with a PIC, as long as
it doesn't have to work in general traffic situations), resolution and
precision of 1 km/h should be enough. It should also stop in case of a
collision -- also not rocket science, can be done by the same PIC.
- Get a driver for it. Alternatively you could use the line follower Tony
Nixon is developing -- I'm sure he appreciates test options.
- Place yourself in the trajectory of the car (on the line in the case of
using the line follower).
- Start the car, running at 1 km/h, towards you. This could be done by a
PIC controlled remote.
- Repeat this, with increasing speed, until you feel unconfortable with the
collisions. For storing the results, I (OT!) suggest a notebook. (Could
also be done with a PIC, though...)

At this point you may consider increasing or not. If speed is not a factor
in all this, increasing the speed should not affect your feeling
(un)comfortable with the collisions. If it seems that increasing the speed
indeed does make it increasingly uncomfortable, we still have not a clear
cause-effect relationship, not even a statistical relationship (after all,
it was only one sample out of the human race), but it may be a strong
enough indication to warrant further research whether the speed of moving
cars is actually involved in determining the amount of damage at collision,
or whether the color of the paint or the medium length of the driver's
hairs are the more determining factors.

Somebody really convinced could go on and continue, passing the "comfort
zone" and stepping into the "hospital zone." I just fear that the time it
will take between test runs may get increasingly longer with each speed
step, and maybe that's the reason why we until today don't have conclusive,
and statistically reasonably certain, data available for answering this
question beyond any doubt.

ge

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2001\11\05@164858 by Peter L. Peres

picon face
> I have no idea about this "credible work", but as a layman in the
> subject, the speed of light does seem to make the assumption that
> time is constant. Is it ?
> Wrap your mind around that one. :-)

No, it assumes that length is constant ;-) ;-).

As another layman, I think that the speed of light barrier is challenged
at the quantic level where you can have quanta that travel slower than
light, but very near it, and it can be shown that due to the incertitude
principle (Heisenberg) there is a certain probability that they go faster
than light at least for some of the time.

In general at the quantic level the speed of light is hard to 'quantify' I
think. I.e. how do you measure the seconds and the meters and what happens
when the incertitude principle is applied to the measurement near the
limit.

Along the same lines it may be possible to send photons at least beyond
the speed of light (I know how this sounds) by using a version of the
experiment that generates photon pairs with well controlled states so the
uncertainity principle can be 'violated' for the particle that was not
analyzed (and thus destroyed).

Peter

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2001\11\05@170150 by Russell McMahon

picon face
> And on the other point.  Can you have absolute speed?  I thought it was
> relative.

That was intended as a joke (many seemed to miss this) based on "Power
corrupts, ... "

However, the speed of light IS absolute, measured in all reference frames.
Strangely. This is an utterly bizarre fact by any common standards and
should have set alarm bells ringing well before Einstein and given us long
pause for thought ever since. The special theory of relativity can be
derived using basic geometry and high school level skills given only the
above "fact" as an assumption.

Photons travel everywhere at, and only at, the speed of light but, from
their own perspective, do so instantaneously and timelessly. (The apparent
contradiction occurs due to limits considerations as time approaches zero.)
For all photons everything everywhere always happens instantaneously no
matter where WE think things fit in time sequence. Does that sound absolute
enough :-) ?




       Russell McMahon

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2001\11\05@173017 by Jinx

face picon face
> However, the speed of light IS absolute, measured in all reference frames.

Comments on this ?

http://www.compu-web.com/ftl.htm

"Speeds measured on this device exceeded 9x the speed of light,
within the frame of reference of this tunnel"

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2001\11\05@174459 by uter van ooijen & floortje hanneman

picon face
> > However, the speed of light IS absolute, measured in all reference
frames.
> Comments on this ?
> http://www.compu-web.com/ftl.htm
> "Speeds measured on this device exceeded 9x the speed of light,
> within the frame of reference of this tunnel"

Look carefully at what is claimed: it does NOT claim that light (or in fact
any physical object) travels faster than light. What 'travels' is a
phenomenon. The speed of light (or any phyiscal object) is still limited.
Without the need for a highway patrol to enforce it, or maybe those guys are
just too damn fast for us to see?

Wouter van Ooijen

Van Ooijen Technische Informatica: http://www.voti.nl
Jal compiler for PIC uC's:  http://www.voti.nl/jal

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2001\11\05@174935 by rad0

picon face
ah, but what of the 'medium' the light is traveling in...

what if you could 'move' it...

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2001\11\05@175747 by Sean H. Breheny

face picon face
Hi Jinx,

I only had time to skim the site, but it looks to me as though he is just
re-hashing the already well known ability of light to travel with a phase
velocity much higher than the speed of light(c). However, this does not
mean that you can communicate with a time delay less than distance/c
because communication requires that you send something other than an
unmodulated wave, and then what really matters is the energy velocity (or
the group velocity in most practical situations).

I find the page (and his paper on the subject, the one you can get to by
the link at the bottom of the page) uses somewhat ambiguous language and
examples. I'd like to see a clear diagram of what his setup is like (not a
photograph, but a block diagram) and exactly what he is measuring. It is
easy to demonstrate a wave traveling faster than the speed of light, but it
matters what your definition of speed is. You have to choose some point on
the wave to consider as the point that you will track as you measure the
speed, and this is not well defined for such dispersive situations as he is
using (i.e., for a pulse, the pulse shape you get out of the system will be
highly distorted from the one going in, so how do you tell which point on
the output corresponds to the one you chose on the input?)

He also claims that there are some deep implications of quantum mechanics
here because classical theory assumes that a detector can work with an
arbitrarily small amount of energy, but in the short time I had to skim it,
I didn't understand what he was claiming were the consequences of this.

It seems to me that his claim that an evanescent wave "spends no time in
the gap" because there is no variation in the spatial distribution over
time to be silly. You can say the same thing about a standing wave. The
evanescent solution only happens for the steady-state case, pulses do not
propagate instantly across an air gap in a prism (or down an undersized
waveguide).

Sean

At 11:29 AM 11/6/01 +1300, you wrote:
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2001\11\05@180320 by Jinx

face picon face
> > http://www.compu-web.com/ftl.htm

> Look carefully at what is claimed: it does NOT claim that light (or in
> fact any physical object) travels faster than light. What 'travels' is a
> phenomenon

I didn't quite understand the comment "We cannot observe any signal
moving faster than light" after all the talk of signals and waves arriving
at targets ahead of simultaneously photons sent by other pathways. Do
they mean DIDN'T, CAN'T (with current technology) or will NEVER see
them because they are impossibilities ?

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2001\11\05@181030 by Jinx

face picon face
> It seems to me that his claim that an evanescent wave "spends no time
> in the gap" because there is no variation in the spatial distribution over
> time to be silly. You can say the same thing about a standing wave. The
> evanescent solution only happens for the steady-state case, pulses do not
> propagate instantly across an air gap in a prism (or down an undersized
> waveguide).
>
> Sean

People such as Stephen Hawking and Kip Thorn support the idea of
quantum time tunneling. They are small and ephemeral events (ruling
out any notion of time/space travel for great big hairy humans) that could
possibly have particles sent in to them. Where/if the particles emerge
in the universe is anyone's guess. They might even come out in another
universe. Time is theorised as being pan-universal in many more than 3
dimensions, anything is possible

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2001\11\06@022215 by dr. Imre Bartfai

flavicon
face
Hi,

I would correct a single word the statement below make (more) true:

RELATIVE speed kills absolutely. E. g. if a bullet has a relative speed of
about 500 mph to its target. If one can ride as fast as the bullet and to
the same direction - no harm.

Regards,
Imre

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On Mon, 5 Nov 2001, Alan B. Pearce wrote:

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2001\11\06@023312 by dr. Imre Bartfai

flavicon
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A remark making things not so simple:

In the U.S.A. I heard (please correct if I'm wrong) it is everyman's right
(even if restricted in some states) to possess and carry a gun. They think
it is a fundamental element of freedom. People who are against this will
be told: "the man kills not the gun". I think it is true, but there is a
statistical correlation: the more the guns the more the number of murders
done by shooting weapons.

See the parallelism:

In the Federal Republic of Germany, there is no speed limit on highways.
They think it is a fundamental element of freedom. People who are against
this will be told: "the bad driving behavior kills not the speed". I
think it is true, but there is a statistical correlation: the higher the
guns the more the number of deaths caused by traffic accident.

And the moral of the story:

A government could make clever regulations. But: it does not fit to
everybody. And any limitations cause loss of votes by the next
election. So they won't do any fundamental changes.

Regards,
Imre



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2001\11\06@024920 by Jinx

face picon face
> RELATIVE speed kills absolutely. E. g. if a bullet has a relative speed of
> about 500 mph to its target. If one can ride as fast as the bullet and to
> the same direction - no harm.
>
> Regards,
> Imre

I find news reports annoying when they are describing a traffic accident
and say the cars collided head-on at, for example, "a combined speed
of 150mph"

Like your bullet, it makes no difference if you're doing 75mph and hit a
wall head-on or a car head-on. You still deccelerate from 75 to 0 in a big
hurry. Anything caught in the car sandwich would experience 75mph
forces on either side though

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2001\11\06@030744 by Dennis Noordsij

flavicon
face
Hi,

> Like your bullet, it makes no difference if you're doing 75mph and hit a
> wall head-on or a car head-on. You still deccelerate from 75 to 0 in a big
> hurry.

Actually if you hit the wall head-on you hit it with 75mph, but if you hit a
car head-on which is also doing 75mph in your direction it is the same thing
as hitting a wall at 150mph, or your car doing 150mph and hitting a car
head-on which is not moving. There most certainly is a difference. A
collision with a "combined speed of 150mph" is quite a horrible accident and
both parties experienced an impact at that speed, not at 75mph.

Of course a wall is less forgiving than another car, but I wouldn't want to
try either option :-)

Dennis

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2001\11\06@035340 by Jinx

face picon face
> > Like your bullet, it makes no difference if you're doing 75mph and
> > hit a wall head-on or a car head-on. You still deccelerate from 75 to
> > 0 in a big hurry.
>
> Actually if you hit the wall head-on you hit it with 75mph, but if you hit
> a car head-on which is also doing 75mph in your direction it is the
> same thing as hitting a wall at 150mph, or your car doing 150mph and
> hitting a car head-on which is not moving

OK, I thought about it this way, maybe you're right. If you were in a
stationary vehicle (or even a stationery vehicle if you were delivering
office supplies) and a car hit you at 75mph, that would sting. So if you
were travelling at 75mph also and hit head-on.......

What I'd reasoned was that at the point of impact you as a vehicle have
deccelerated from 75 to 0 and stopped at exacty the same point you
would have if you'd hit a stationary wall. Hmmm, still not convinced
about that "combined speed" thing

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2001\11\06@042626 by Dennis Noordsij

flavicon
face
> What I'd reasoned was that at the point of impact you as a vehicle have
> deccelerated from 75 to 0 and stopped at exacty the same point you
> would have if you'd hit a stationary wall. Hmmm, still not convinced
> about that "combined speed" thing

:-)

As for deceleration, you'd be right. But imagine being a wall, in a
stationary position, and having a car hit you at 75mph. You wouldn't move, or
change speeds, you're at 0 mph at all times. It would still hurt right? :-)

Basically in the "combined speed" case there is twice as much energy (in the
form of kinetic energy) that has to go somewhere, and now both cars absorb
that amount. In the case of one car vs. a wall there is only half of that
amount of kinetic energy. However the wall will feel it just as much as the
car :) You could say that half of your kinetic energy is transferred to the
object you hit, so if you hit another car you receive half it's energy plus
your own half, in the case of a wall you only get your own half and none of
the wall because it has none (it is not moving).

Of course it is not exactly half, it all depends on the type of object, its
mass compared to yours, etc. Obviously if you're a VW and hit a bicycle at a
combined speed of 100mph it'll be a different experience than hitting a big
truck at that speed :) Also a wall is a bad object to hit because it usually
does not move or buckle (so you absorb most of the impact), whereas another
car would at least "bounce" back a bit and forces are more equally
distributed.

Best thing to do though is not crash at all!

Regards,
Dennis

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2001\11\06@052244 by Jinx

face picon face
> :-)
>
> As for deceleration, you'd be right. But imagine being a wall, in a
> stationary position, and having a car hit you at 75mph. You wouldn't
> move, or change speeds, you're at 0 mph at all times. It would still
> hurt right? :-)

Ah, but what if you were inside a wall that didn't move ? ;-)))

> Basically in the "combined speed" case there is twice as much energy (in
> the form of kinetic energy) that has to go somewhere, and now both cars
> absorb that amount. In the case of one car vs. a wall there is only half
of
> that amount of kinetic energy. However the wall will feel it just as much
as
> the car :) You could say that half of your kinetic energy is transferred
to the
> object you hit, so if you hit another car you receive half it's energy
plus
> your own half, in the case of a wall you only get your own half and none
of
> the wall because it has none (it is not moving).

It's late - my brain hurts

Say you got two pendulums (pendula ?) that could record the force of
an impact - I'm sure in my own mind (which still hurts btw) that if you let
them swing together and hit, each would show half the energy in the
collision. Which I think is my point. Two cars, two speeds, two momenta
(ah ha !) but also two objects to share the impact. Reasonable ? All has
been conserved

> Of course it is not exactly half, it all depends on the type of object,
its
> mass compared to yours, etc. Obviously if you're a VW and hit a bicycle
> at a combined speed of 100mph it'll be a different experience than
> hitting a big truck at that speed :)

And also for the VW driver who just hit me. Imagine - a very irate fit
cyclist
with steel-capped boots on "wants a word"

> Best thing to do though is not crash at all!

Gadzooks !!!! I'll try to remember that ;-))))))

> Regards,
> Dennis

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2001\11\06@053221 by Russell McMahon

picon face
> I would correct a single word the statement below make (more) true:
>
> RELATIVE speed kills absolutely. E. g. if a bullet has a relative speed of
> about 500 mph to its target. If one can ride as fast as the bullet and to
> the same direction - no harm.



Aaaarghhhhhh !!!!!!       :-)
It was a joke guys !

Original

"Power corrupts. Absolute power corrupts absolutely."

Changing this to "relative" would suggest -

   "Power corrupts. Relative power corrupts relatively." :-)

True, but lacks the impact (no pun intended.)

Also, re absolute speed killing, see my prior post which "proved" that
absolute speed MUST result in death :-)
(you must be comprised solely of photons and travel at light-speed.)


       RM.

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2001\11\06@053332 by Dennis Noordsij

flavicon
face
> Say you got two pendulums (pendula ?) that could record the force of
> an impact - I'm sure in my own mind (which still hurts btw) that if you let
> them swing together and hit, each would show half the energy in the
> collision. Which I think is my point. Two cars, two speeds, two momenta
> (ah ha !) but also two objects to share the impact. Reasonable ? All has
> been conserved

In your own words then:

2 cars hitting head-on at 75mph each or 150mph combined, 2 momenta, shared
between 2 objects, 1 momentum per object.

1 car hitting a wall at 75mph, 1 momentum, shared between 2 objects, 1/2
momentum per object.

So in the second case the car absorbs less energy than in the first case (1/2
a momentum vs. a whole momentum).

:-)

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2001\11\06@055117 by Jinx

face picon face
> > (ah ha !) but also two objects to share the impact. Reasonable ? All has
> > been conserved
>
> In your own words then:

Oh, don't believe anything "I" say ;-))

> 2 cars hitting head-on at 75mph each or 150mph combined, 2 momenta,
> shared between 2 objects, 1 momentum per object.
>
> 1 car hitting a wall at 75mph, 1 momentum, shared between 2 objects, 1/2
> momentum per object.
>
> So in the second case the car absorbs less energy than in the first case
(1/2
> a momentum vs. a whole momentum).

Code Red Code Red, Westie down, Westie down !!!!!!! Russell, HELP !!!!!

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2001\11\06@080016 by Gerhard Fiedler

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At 21:31 11/06/2001 +1300, Jinx wrote:
> > > Like your bullet, it makes no difference if you're doing 75mph and
> > > hit a wall head-on or a car head-on. You still deccelerate from 75 to
> > > 0 in a big hurry.
> >
> > Actually if you hit the wall head-on you hit it with 75mph, but if you hit
> > a car head-on which is also doing 75mph in your direction it is the
> > same thing as hitting a wall at 150mph, or your car doing 150mph and
> > hitting a car head-on which is not moving
>
>OK, I thought about it this way, maybe you're right. If you were in a
>stationary vehicle (or even a stationery vehicle if you were delivering
>office supplies) and a car hit you at 75mph, that would sting. So if you
>were travelling at 75mph also and hit head-on.......
>
>What I'd reasoned was that at the point of impact you as a vehicle have
>deccelerated from 75 to 0 and stopped at exacty the same point you
>would have if you'd hit a stationary wall. Hmmm, still not convinced
>about that "combined speed" thing

The missing thing is the "softness" of a car. Considering an "ideal" wall
(something that doesn't move at all, ideally stiff), hitting such a wall at
any speed is about the same as hitting a car with the same mass head on at
the same speed. But hitting a car with the same mass that stands still is
going to be half the impact. So, considering that they were talking about a
car-to-car  collision, the combined speed does count.

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2001\11\06@095726 by t F. Touchton

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I have to disagree with you... you have approximately twice as much energy
being absorbed by the cars.

Scott F. Touchton
1550 Engineering Manager
JDS Uniphase



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I find news reports annoying when they are describing a traffic accident
and say the cars collided head-on at, for example, "a combined speed
of 150mph"

Like your bullet, it makes no difference if you're doing 75mph and hit a
wall head-on or a car head-on. You still deccelerate from 75 to 0 in a big
hurry. Anything caught in the car sandwich would experience 75mph
forces on either side though

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2001\11\06@101222 by Roman Black

flavicon
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Jinx wrote:

> OK, I thought about it this way, maybe you're right. If you were in a
> stationary vehicle (or even a stationery vehicle if you were delivering
> office supplies) and a car hit you at 75mph, that would sting. So if you
> were travelling at 75mph also and hit head-on.......
>
> What I'd reasoned was that at the point of impact you as a vehicle have
> deccelerated from 75 to 0 and stopped at exacty the same point you
> would have if you'd hit a stationary wall. Hmmm, still not convinced
> about that "combined speed" thing


Umm, sure in both cases you decelerate from
75 to 0, but when you hit the oncoming car you
decelerate twice as fast?? That's bad. :o)
-Roman

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2001\11\06@110028 by Gerhard Fiedler

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At 09:54 11/06/2001 -0500, Scott F. Touchton wrote:
>I have to disagree with you... you have approximately twice as much energy
>being absorbed by the cars.

Twice as much by _two_ cars... :)  If you run one car into a completely
(ideally) stiff wall, it's the energy of one car absorbed by one car,
because the stiff wall doesn't absorb anything, so in this two cases, every
car absorbes the same energy, no matter whether it's one car against a wall
or two cars against each other. (A different thing is a car against a
standing car.)

ge

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2001\11\06@115108 by Lee Jones

flavicon
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>> OK, I thought about it this way, maybe you're right. If you were in a
>> stationary vehicle (or even a stationery vehicle if you were delivering
>> office supplies) and a car hit you at 75mph, that would sting. So if you
>> were travelling at 75mph also and hit head-on.......
>>
>> What I'd reasoned was that at the point of impact you as a vehicle have
>> deccelerated from 75 to 0 and stopped at exacty the same point you
>> would have if you'd hit a stationary wall. Hmmm, still not convinced
>> about that "combined speed" thing

> Umm, sure in both cases you decelerate from
> 75 to 0, but when you hit the oncoming car you
> decelerate twice as fast?? That's bad. :o)

No.  Why would you decelerate twice as fast?  The occupants
of each vehicle are moving at 75MPH -- no faster.  Each one
decelerates to 0MPH.  If the vechicles are _equal mass_ and
collide with perfectly aligned force vectors, then it is
symmetrical.  Each vehicle consumes 1/2 of the kinetic energy
and experiences the same deceleration as hitting a huge
immovable object.

                                               Lee Jones

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2001\11\06@154452 by Peter L. Peres

picon face
> ah, but what of the 'medium' the light is traveling in...
>
> what if you could 'move' it...

imho go find an dread an article about 'freezing' light (more exactly
slowing it down to a stop. I think that it was in Scientific American.

Peter

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2001\11\06@210934 by Bob Ammerman

picon face
Here is a thought experiment:

Three cases:

1: An automobile travelling at 75 miles per hour crashes into an "immovable
object" or wall. In this case the automobile decelerates from 75 to zero in
whatever distance is required for the energy to be absorbed by the crushing
of the car.

2. Two automobiles travelling at 75 miles per hour each crash together.
Again, they will decelerate to zero in whatever distance is required for the
energy (twice as much of it) to be absorbed by the crushing of the car(s) (2
of them).

3. Now imagine that the two cars simultanously crash into opposite sides of
a non-compressisble piece of paper. As each car collapses into the paper the
other 'sees' an "immovable object" through the paper and thus experiences
the same forces as case 1.

Now, obviously the presence of a piece of paper won't really make any
difference, so I vote for the opinion that the forces encounted by the
automobile and its occupants are the same in all three cases above. This
assumes, of course, that the wall is indeed "imnmovable" (and
non-compressibnle) and doesn't absorb any of the energy of the collision.

I think the reason the two-car collision isn't 'worse' than the car-wall
collision is shown above.

On the other hand, if a car travelling at 75 miles per hour collided with a
wall moving at 75 miles per hour...

Bob Ammerman
RAm Systems


{Original Message removed}

2001\11\07@062929 by dr. Imre Bartfai

flavicon
face
With one exception: if both cars have the speed 75 mph and they collide
(run against each other) then the relative speed is to be added and the
energy is four times high.

Imre

On Tue, 6 Nov 2001, Jinx wrote:

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2001\11\07@074225 by Dennis Noordsij

flavicon
face
> assumes, of course, that the wall is indeed "imnmovable" (and
> non-compressibnle) and doesn't absorb any of the energy of the collision.

Why does a pedestrian walking into the side of a stationary bus doesn't do
much for the bus? Because the energy the pedestrian has is not nearly enough
to even mildly shake the big heavy buss.

In your case of a "perfect wall", a material that is so strong and heavy and
well connected (unmovable) to the ground, a car hitting it at 75mph will look
like a pancake and the wall wouldn't have a scratch.

STILL, more energy is released when 2 cars hit each other head-on at 75mph
each. Pretty basic physics, the wall doesn't have energy, and 2 cars at 75mph
have more energy than 1 car at 75mph. This can not be argued. The piece of
paper in your example is an optical illusion for the driver, but he is
definately not hitting a stationary object with no energy of it's own, he is
hitting the other car which is going 75mph.

With that out of the way, there are of course lots of other factors involved
that determine wether it is "better" to be in one kind of a collision or the
other. A wall for example tends to not move, so all the energy goes into
flattening your car.

When you hit another car, part of the energy bounces the cars off each other,
and even though you will happy you're wearing a seatbelt when you go from
75mph to 0mph in 0.2 seconds, it doesn't necessarily fold your car into what
a wall would make out of it. You'll probably also rotate around each other,
or one car goes on top of the other car, etc. Best example, in a collision
your car might end up flying 50 feet through the air, and land upside down
but pretty much intact. When you hit a wall there's nowhere to fly and the
energy that is released (albeit less than in the other example) is much more
destructive.

The amount of energy released does not necessarily indicate the amount of
damage done.

SO:
1. "combined speed" is very relevant when talking about car-car collisions.
BUT:
2. How you walk away from the accident depends more on HOW the energy release
manifests itself rather than just the amount.

Any takers? :-))

Regards,
Dennis

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2001\11\07@081846 by J.Feldhaar

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Hi Dennis,

I have a remark on this subject....

Dennis Noordsij schrieb:

 
In your case of a "perfect wall", a material that is so strong and heavy and
well connected (unmovable) to the ground, a car hitting it at 75mph will look
like a pancake and the wall wouldn't have a scratch.
 


Correct - mostly...

 
STILL, more energy is released when 2 cars hit each other head-on at 75mph
each. Pretty basic physics, the wall doesn't have energy, and 2 cars at 75mph
have more energy than 1 car at 75mph. This can not be argued. The piece of
paper in your example is an optical illusion for the driver, but he is
definately not hitting a stationary object with no energy of it's own, he is
hitting the other car which is going 75mph.
 


Your Honor, I have an objection. A stationary wall can still exert a mechanical force. Science tells us that a stationary (not moving...!) wall (sic) will not move because it exerts the exact amount of force back that is applied on to the wall.
Imagine yourself pressing your hands together. Each hand exerts the same force, so they don't move. Now take one hand (the wall) away, and the other hand will not remain stationary either.
They call it mechanics....

Greets
Jochen Feldhaar DH6FAZ

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2001\11\07@085001 by Bob Ammerman

picon face
Imre,

But where does that energy come from? A certain amount of energy,
proportional to the square of 75mph as used to accelerate each of the cars.

If the energy available in the collision were to be proportional to the
square of 150mph then a lot of energy has appeared out of nowhere.

Anybody want to build a perpetual motion machine based on this principal?

Bob Ammerman
RAm Systems

{Original Message removed}

2001\11\07@091539 by Dennis Noordsij
flavicon
face
Hi Jochen,

Can you configure your mail client not to send HTML to this list? I'm sure
most people would prefer that :-)

> <p><br>Your Honor, I have an objection. A stationary wall can still exert
> a mechanical force. Science tells us that a stationary (not moving...!)
> wall (sic) will not move because it exerts the exact amount of force back
> that is applied on to the wall.
> <br>Imagine yourself pressing your hands together. Each hand exerts the
> same force, so they don't move. Now take one hand (the wall) away, and
> the other hand will not remain stationary either.
> <br>They call it mechanics....

Well .. I guess you're right. I was only trying to find a good way to show
that 2 moving cars will release more energy in a collision than 1 car and a
wall, and to go all the way back to the message that started this can of
worms, that "combined speed" matters in a head-on collision.

Even though I didn't introduce it in the proper mechanical terms, I did
mention the object you crash into matters. For exactly the reason the wall
will not move, your car turns into a pancake. (So could I say that you exert
a force on the wall with your car by hitting it, and by not moving the wall
exerts a force back, and your car ends up "sandwiched" by those forces?).

I would be interested to hear your take on the whole subject :-) I would like
know if I'm fundementally wrong (which I am not claiming I am not). It's just
interesting :)

Regards,
Dennis

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2001\11\07@091547 by t F. Touchton

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Energy is relative to velocity and mass.  So... one car traveling at 75mph
will impart energy equating to the square of its velocity and mass.  If you
hit another car traveling towards you at 75mph, it is the same as hitting a
fixed object at the relative speed, 150mph.  Much more energy... I was
wrong about the twice part, it is a squared relationship.  So you have 4
times the energy being imparted onto both cars (so each will see twice as
much if the masses are the same).

Scott F. Touchton
1550 Engineering Manager
JDS Uniphase



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At 09:54 11/06/2001 -0500, Scott F. Touchton wrote:
>I have to disagree with you... you have approximately twice as much energy
>being absorbed by the cars.

Twice as much by _two_ cars... :)  If you run one car into a completely
(ideally) stiff wall, it's the energy of one car absorbed by one car,
because the stiff wall doesn't absorb anything, so in this two cases, every
car absorbes the same energy, no matter whether it's one car against a wall
or two cars against each other. (A different thing is a car against a
standing car.)

ge

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2001\11\07@092004 by Gerhard Fiedler

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The problem with Imre's scenario is that he puts the reference into one of
the cars, but if we're talking about energy balances, neither car has been
moving with a constant speed (as it has been accelerating with respect to
the road). The energy balance of a system (including the road) with the
reference in an accelerating and decelerating car is more than complex, I
suppose... :)

So I guess we better stick with the reference of the road, and have twice
the energy of each car, each car transforming approx. its own kinetic
energy into deformation and heat, basically :)

At 08:49 11/07/2001 -0800, Bob Ammerman wrote:
{Quote hidden}

>{Original Message removed}

2001\11\07@103408 by Jeszs

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I do not foolow this from the begining. Sorry if I am repeating.

The kinetic energy is relative to the coordinate system one is taking as reference. For the subject example, in order to have our mobiles with constant velocity, the reference should be inertially moving (zero or constant velocity). Cars are considered equal mass.

Case 1: reference attached to the road (Vref=0)
   Before: Car A: VAb= +75 km/h, Car B: VBb= -75 km/h, difference velocity = 150 Km/h
               Kbefore = 0.5 * 75^2 * M
   After: Car A: VAb= 0 km/h, Car B: VBb= 0 km/h
               Kafter = 0.5 * 0 * M = 0
   Crash energy: Kbefore - Kafter = 0.5 * 75^2 * M

Case 2: reference attached to the road (Vref=0)
   Before: Car A: VAb= 0 km/h, Car B: VBb= -150 km/h, difference velocity = 150 Km/h
               Kbefore = 0.5 * 150^2 * M
   After: Car A: VAb= -75 km/h, Car B: VBb= -75 km/h (recall momentum conservation: M * V = const)
               Kafter = 0.5 * 75^2 * M + 0.5 * 75^2 * M
   Crash energy: Kbefore - Kafter = 2 * 0.5 * 75^2 * M               => Same as Case1

Case 3: reference moving 75 km/h left to right (Vref=+75Km/h)
   Before: Car A: VAb= 0 km/h (moving same speed as reference), Car B: VBb= -150 km/h, difference velocity = 150 Km/h
               Kbefore = 0.5 * 150^2 * M
   After: Car A: VAb= -75 km/h, Car B: VBb= -75 km/h (reference is still moving right)
               Kafter = 0.5 * 75^2 * M + 0.5 * 75^2 * M
   Crash energy: Kbefore - Kafter = 2 * 0.5 * 75^2 * M               => Same as Case1 and Case2

Case 4: reference moving 100 km/h left to right (Vref=+100Km/h)
   Before: Car A: VAb= -25 km/h (moving leftwards from reference), Car B: VBb= -175 km/h, difference velocity = 150 Km/h
               Kbefore = 0.5 * 25^2 * M + 0.5 * 175^2 * M
   After: Car A: VAb= -100 km/h, Car B: VBb= -100 km/h (recall momentum conservation: M * V = const)
               Kafter = 0.5 * 100^2 * M + 0.5 * 100^2 * M
   Crash energy: Kbefore - Kafter = 2 * 0.5 * 75^2 * M               => Same as above (CHECK IT OUT!!)

In all cases it is true that the energy dedicated to deformation of both cars is 0.5 * (0.5 * Vdif^2 * M) and hence I think it makes sense to speak of the differential velocity to assess the severity of the hit.

Finally, one can repeat the exercise with a static wall (that could be dynamic if you move your reference) and see why it is not (at all) similar to go against a wall than against another car with identical mass. Change the mass of the target car and you will have the whole spectrum of posiblilities.

Hope this clarifies something.

------------------------------
Jesús Gonzalo
Leon (SPAIN)
------------------------------

{Quote hidden}

2001\11\07@140653 by Peter L. Peres

picon face
> 1 car hitting a wall at 75mph, 1 momentum, shared between 2 objects, 1/2
> momentum per object.

Momentum or impulse or cinetic energy are written vs. speed. The speed of
the wall is zero, thus its momentum/cinetic energy/impulse is zero. Only
the car brings some to the meeting.

Peter

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2001\11\07@143057 by Peter L. Peres

picon face
> Say you got two pendulums (pendula ?) that could record the force of
> an impact - I'm sure in my own mind (which still hurts btw) that if you
> let
> them swing together and hit, each would show half the energy in the
> collision. Which I think is my point. Two cars, two speeds, two momenta
> (ah ha !) but also two objects to share the impact. Reasonable ? All has
> been conserved^H^H^H^H^H^H^H

...transformed. Into heat. Cars crumple. Dennis is right, there is twice
as much energy involved with two cars, but there are TWO cars to wreck
with it. Each takes 1/2 of the double energy so each takes only what it
came with.

Peter

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2001\11\07@143107 by Peter L. Peres

picon face
> And the moral of the story:
>
> A government could make clever regulations. But: it does not fit to
> everybody. And any limitations cause loss of votes by the next
> election. So they won't do any fundamental changes.

In a 'properly functioning' democracy (cough, cough) most such small
mundane issues like speed regulation, no smoking laws and gun laws and
other local laws are usually handled by minority factions who got into the
government by virtue of voting or supporting someone else who then lets
them do their small thing while he/they handle more major issues. The
result is, that most strange local laws, such as gun laws, smoking,
speeding ($SUBJ) etc. are established by a democratic MINORITY. They also
tend to come and go quickly...

Peter

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2001\11\07@143110 by Peter L. Peres

picon face
> Like your bullet, it makes no difference if you're doing 75mph and hit
> a wall head-on or a car head-on. You still deccelerate from 75 to 0 in
> a big hurry. Anything caught in the car sandwich would experience
> 75mph forces on either side though

If you want to compare energies then let's compare energies. A M16 bullet
has about 1800J at the muzzle. A 100kg man jumping from 2 meters onto
concrete has about 2000J and he will likely sustain some damage from that
jump (try to think about jumping barefoot into an empty pool at the deep
side). A 100kg man in a car travelling at 23 km/h (km/h -> m/sec = *0.27)
or ~6.3 m/sec has the same amount of energy. If his car hits a tree or
concrete or another car head on and the bonnet is shorter than 2 meters he
will sustain about the same amount of damage as jumping from 2 meters. The
energy in a travelling person or object increases with the square of the
speed so you compute what a head on collision makes at 50km/h etc.
Probably speed limitations above 80km/h are meant to keep people with
slower reflexes from hitting each other and surrounding objects, for the
lot of difference it would make in a real collision.

Peter

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2001\11\07@143809 by Peter L. Peres

picon face
> Actually if you hit the wall head-on you hit it with 75mph, but if you
> hit a car head-on which is also doing 75mph in your direction it is
> the same thing as hitting a wall at 150mph, or your car doing 150mph
> and hitting a car head-on which is not moving. There most certainly is
> a difference. A collision with a "combined speed of 150mph" is quite a
> horrible accident and both parties experienced an impact at that
> speed, not at 75mph.

Two identical cars of same masses travelling in opposite directions with
75mph (or any other speed) each and hitting each other perfectly head on
will each sustain the exact same damage as if each car would hit a wall
head on by itself, at 75mph, not 150mph. This is very basic collision
analysis ?

I do not count on news media to notice such things. Or rather, I do,
because if the combined speed was 150mph then each was probably doing 70
to 80mph and was thus legal. Accidents committed while driving with legal
speed do not make an argument in an article about speed that kills, so the
editor in chief had it 'rectified' for the unwashed masses ;-).

Peter

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2001\11\07@144650 by Jinx

face picon face
> If the energy available in the collision were to be proportional to the
> square of 150mph then a lot of energy has appeared out of nowhere.
>
> Anybody want to build a perpetual motion machine based on this
> principal?

Hmmm, interesting proposal, but you'd need Bill Gates' money to buy
rather a lot of cars and it would be a bloody noisy machine !!!! ;-))

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2001\11\07@152616 by uter van ooijen & floortje hanneman

picon face
> STILL, more energy is released when 2 cars hit each other head-on at 75mph
> each. Pretty basic physics, the wall doesn't have energy, and 2 cars at
75mph
> have more energy than 1 car at 75mph. This can not be argued. The piece of
> paper in your example is an optical illusion for the driver, but he is
> definately not hitting a stationary object with no energy of it's own, he
is
> hitting the other car which is going 75mph.

When two cars hit each other head-on, or one car hits the wall, the amount
of energy available per car is the same (assiming the wall does not absorb
energy). As you say, this can not be argued. The piece of paper is just a
clue for the mind, but it illustrates the situation very good: when the two
cars hit in a 'perfect' way (exactly
symmetrical) the paper won't even move.

Of course the situation when a car hits a stationary car (or a non-perfect
wall) is very different: now the energy will be divided over the two
objects, and maybe the tangle is still moving after the crash, so some
energy is not spend in deforming the cars.

So

Wouter van Ooijen
Van Ooijen Technische Informatica: http://www.voti.nl
Jal compiler for PIC uC's:  http://www.voti.nl/jal

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2001\11\07@191700 by John Ferrell

flavicon
face
RE:
>
> In the U.S.A. I heard (please correct if I'm wrong) it is everyman's right
> (even if restricted in some states) to possess and carry a gun. They think
> it is a fundamental element of freedom. People who are against this will
> be told: "the man kills not the gun". I think it is true, but there is a
> statistical correlation: the more the guns the more the number of murders
> done by shooting weapons.
>
We are a strange culture. Statistics in the State of North Carolina indicate
correlation of a lower crime rate with the passing of legislation allowing a
person to Carry a Concealed Weapon.  That person does have to permit and pay
for a background check by the local law enforcement. The law does not excuse
any mis use of any wepon.

Car jackings were beginning to be rather common. After the law they have all
but disappeared.  We like it this way...
John Ferrell
6241 Phillippi Rd
Julian NC 27283
Phone: (336)685-9606
Dixie Competition Products
NSRCA 479 AMA 4190  W8CCW
"My Competition is Not My Enemy"



{Original Message removed}

2001\11\07@192505 by David VanHorn

flavicon
face
>
>We are a strange culture.


Maybe, but the facts remain.

Criminals, by definition, do not obey the law.
Making it illegal to rob me is therefore ineffective.
Making it illegal to use a gun to rob me is likewise ineffective.

Disarming me makes it safe(r) to rob me.
This is interesting to the robber.

Allowing me to be armed makes robbing me more risky for the robber.
The fact that I may be armed, is definitely interesting to the robber.


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2001\11\07@205431 by Bob Ammerman

picon face
----- Original Message -----
From: "Scott F. Touchton" <EraseMEScott.Touchton@spam@spam@spam@US.JDSUNIPHASE.COM>
To: <@spam@PICLISTspamspamKILLspamMITVMA.MIT.EDU>
Sent: Wednesday, November 07, 2001 6:12 AM
Subject: Re: [ot]: how does a radar detector work?


> Energy is relative to velocity and mass.  So... one car traveling at 75mph
> will impart energy equating to the square of its velocity and mass.  If
you
{Quote hidden}

Again, where does this energy come from? If you can tell me, I'd like to go
into business with you selling perpetual motion machines.


Bob Ammerman
RAm Systems

>
>
>                     Gerhard
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radar detector work?
{Quote hidden}

energy
> >being absorbed by the cars.
>
> Twice as much by _two_ cars... :)  If you run one car into a completely
> (ideally) stiff wall, it's the energy of one car absorbed by one car,
> because the stiff wall doesn't absorb anything, so in this two cases,
every
> car absorbes the same energy, no matter whether it's one car against a
wall
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2001\11\08@093612 by t F. Touchton

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I don't think you would find me a receptive business partner....

Here is where I get confused in the conversation... a single car has the
energy of 1/2 mv^2.  Two cars of identical mass have the combined energy of
mv^2.

So, if one is traveling towards the other, they each impart 1/2mv^2 to the
total impact.


Now, if you bring in the relative part, one car standing still and the
other traveling at 2V, now the energy is 2mv^2 (not the earlier assumption
of mv^2).

I am totally perplexed in this right now.. I would gather that one
assumption is wrong (of course, or I made a stupid math error).

Please find it in your heart to enlighten me... I actually lost sleep over
this!!


Scott




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{Original Message removed}

2001\11\08@095722 by J.Feldhaar

flavicon
face
"Scott F. Touchton" schrieb:
>
> I don't think you would find me a receptive business partner....
>
> Here is where I get confused in the conversation... a single car has the
> energy of 1/2 mv^2.  Two cars of identical mass have the combined energy of
> mv^2.
>
> So, if one is traveling towards the other, they each impart 1/2mv^2 to the
> total impact.
>

After this, they don't move. so energy==0

> Now, if you bring in the relative part, one car standing still and the
> other traveling at 2V, now the energy is 2mv^2 (not the earlier assumption
> of mv^2).
After this, both move with 75 kph (1V), so half of the doubled energy is
still there.....no nobel prize for physics..... ;-(

Greets
Jochen Feldhaar

{Quote hidden}

> {Original Message removed}

2001\11\08@103010 by Eoin Ross

flavicon
face
>> Again, where does this energy come from? If you can tell me, I'd like to go
>> into business with you selling perpetual motion machines.


>> Bob Ammerman
>> RAm Systems

Its High School Physics .........

Crater size is related to the mass(m) and velocity(v) of the impacting body. These two quantities can be combined to find the kinetic energy of an impactor, defined as
K = ½ m v2

where K is the kinetic energy, m is the mass of the impacting body, and v is the velocity of the impactor. Review the results of your crater experiments in section IIA. The size of the crater increased with the mass of the bolide, and also with the height from which it was dropped (which is proportional to the speed of impact). This fundamental physical relationship allows an estimate of bolide mass to be made from crater diameter.

The energy comes from the fuel you burn in acceleration of the mass to it's velocity, The energy expended to keep it moving is to counteract the effects of friction and drag.

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2001\11\08@104006 by t F. Touchton

flavicon
face
Cool... that was the piece of the puzzle I was missing. (I will sleep
tonight).

My physics teacher would shoot me.

Scott F. Touchton




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"Scott F. Touchton" schrieb:
>
> I don't think you would find me a receptive business partner....
>
> Here is where I get confused in the conversation... a single car has the
> energy of 1/2 mv^2.  Two cars of identical mass have the combined energy
of
> mv^2.
>
> So, if one is traveling towards the other, they each impart 1/2mv^2 to
the
> total impact.
>

After this, they don't move. so energy==0

> Now, if you bring in the relative part, one car standing still and the
> other traveling at 2V, now the energy is 2mv^2 (not the earlier
assumption
> of mv^2).
After this, both move with 75 kph (1V), so half of the doubled energy is
still there.....no nobel prize for physics..... ;-(

Greets
Jochen Feldhaar

>
> I am totally perplexed in this right now.. I would gather that one
> assumption is wrong (of course, or I made a stupid math error).
>
> Please find it in your heart to enlighten me... I actually lost sleep
over
> this!!
>
> Scott
>
>                     Bob Ammerman
>                     <rammerman@ADE       To:     PICLISTSTOPspamspamKILLspamMITVMA.MIT.EDU
>                     LPHIA.NET>           cc:
>                     Sent by: pic         Subject:     Re: [ot]: how does
a radar detector work?
{Quote hidden}

> {Original Message removed}

2001\11\08@104404 by Jeszs

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yes, but after the crash you will have TWO cars moving at 1/2(v1+v2). If you substract after and before energy you will see that the energy difference is identical (and proportional to the square of the (v1-v2) initial velocities). I posted case examples yesterday.

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Jesus G.
Leon (SPAIN)
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{Original Message removed}

2001\11\08@113749 by Eoin Ross

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++After this, they don't move. so energy==0

Make that kinetic energy ..... energy is conserved - this energy will have changed into ... heat(kinetic energy of atoms/molecules) from deforming metal/friction, sound (kinetic energy of air particles) and if we assume that is wasn't a dead on collision resulting in zero movement - angular velocity and linear velocity (which is again kinetic energy)

++> Now, if you bring in the relative part, one car standing still and the other traveling at 2V, now the energy is 2mv^2 (not the earlier assumption
++> of mv^2).
++After this, both move with 75 kph (1V), so half of the doubled energy is
++still there.....no nobel prize for physics..... ;-(

++Greets
++Jochen Feldhaar


There is an error here - assume both cars are traveling at 100 kph relative to the ground and directly towards each other .... and each weighs 1000 kg

each car has 1/2m v^2 kinetic energy - or 50,000 something joules each for a total of 100,000 something joules

Relative to car A, car B is doing 200 kph .... which still equates to 100,000 something joules

Assuming a "perfect" collision where each car absorbs the energy of the other car ... we end up with them stationary - and zero relative velocity, hence zero kinetic energy
Another way to look at it is relative to a number line on the ground - zero being the point of impact ...

One car moves in a "positive" direction,  the other "negative", we assign this to their velocities - and get equal but opposite kinetic energies.

At the point of impact we add them together ... and get zero, mass hasn't changed so velocity must be zero.

This can be used for unequal masses. You will get a kinetic energy left over from the addition (and a sign indicating direction of the velocities involved) and from this deduce what speed the two vehicles would be doing (if they stuck together)


Clear as mud?

Eoin Ross

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2001\11\09@112828 by Bob Ammerman

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The point of my comment is that there is no more kinetic energy available
per car in the two car head on collision than there is in the one-car
into-the-wall collision.

Some respondents have felt that because the relative speed of the two cars
in 150MPH the energy available should be:

   1/2 * M * 150 * 150 = 11250 M

Instead of:

   2 * 1/2 * M * 75 * 75 = 5625 M

This is fallacious thinking.

Bob Ammemran
RAm Systems

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2001\11\12@060353 by Roman Black

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Lee Jones wrote:
>
> > Umm, sure in both cases you decelerate from
> > 75 to 0, but when you hit the oncoming car you
> > decelerate twice as fast?? That's bad. :o)

> No.  Why would you decelerate twice as fast?


Because I ride a lightweight motorcycle. ;o)
-Roman

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2001\11\18@160652 by trm

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Roman,

Well said.

Ted

Roman Black wrote:

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