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'Traffic Lights (Was Car LED lighting etc ...)'
1999\07\29@211618 by PJH

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Boy, this must be the longest thread I've seen.

OK, some posters were talking about air traffic control, collision avoidance
etc. Here's a question re traffic control.

In Australia, Melbourne suburbs, lots of traffic lights seem to be synchronised
so that heavy traffic flow on a main road gets all green lights. I always
assumed it was done with simple timers. However, I'm *told* that radar detectors
- you know those little black-box gizmos you put on your dash to defeat the
police? - are set off when approaching these synched lights. ('Course that's
only what I've been told. Heh! Well, I wouldn't  use illegal technology myself,
naturally ..............!)

So, are synched traffic lights controlled with a microwave system somehow?

Just wondering.

PJH

1999\07\29@212032 by Andy Kunz

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>only what I've been told. Heh! Well, I wouldn't  use illegal technology
myself,
>naturally ..............!)

Radar detectors illegal?

In the US, you can own and operate any sort of receiver you desire, no
problem.  Federal law.  (Just don't key the mike unless you are licensed in
some manner.)

Some states, such as Virginia, think they don't have to obey the FCC on
that one.  If I were still there, I'd almost like to take it to the Supreme
Court.  But I don't speed, and never owned one.

Andy

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1999\07\29@212853 by M. Adam Davis

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I know that here the major roads have traffic lights that communicate
with radio.  You see the occasional antenna on top on the light pole, or
near to the light box.

-Adam

PJH wrote:
>
> Boy, this must be the longest thread I've seen.
>
> OK, some posters were talking about air traffic control, collision avoidance
> etc. Here's a question re traffic control.
>
> In Australia, Melbourne suburbs, lots of traffic lights seem to be synchronise
d
> so that heavy traffic flow on a main road gets all green lights. I always
> assumed it was done with simple timers. However, I'm *told* that radar detecto
rs
{Quote hidden}

1999\07\29@213310 by M. Adam Davis

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Not quite, IIRC radar detectors are illegal in some states.  They aren't
allowed to pull you over if they suspect you have one, though.  Only if
they notice it during another infraction of the law.

-Adam

Andy Kunz wrote:
{Quote hidden}

1999\07\29@213933 by Dennis Plunkett

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At 11:11 30/07/99 +1000, you wrote:
>Boy, this must be the longest thread I've seen.
>
>OK, some posters were talking about air traffic control, collision avoidance
>etc. Here's a question re traffic control.
>
>In Australia, Melbourne suburbs, lots of traffic lights seem to be
synchronised
>so that heavy traffic flow on a main road gets all green lights. I always
>assumed it was done with simple timers. However, I'm *told* that radar
detectors
>- you know those little black-box gizmos you put on your dash to defeat the
>police? - are set off when approaching these synched lights. ('Course that's
>only what I've been told. Heh! Well, I wouldn't  use illegal technology
myself,
{Quote hidden}

Are, uhm NO.
Sync traffic lights are via telephone lines (Also provides communications
to the signal control centre) (Notticed how the "In case of faults call
131360 and quote this number" sign is gone?)
This is so for the city area as it allows VIC roads to alter sequences
during heavy traffic times.

Dennis

1999\07\29@214129 by Nick Taylor

picon face
Andy Kunz wrote:
>
> >only what I've been told. Heh! Well, I wouldn't  use illegal technology
> myself,
> >naturally ..............!)
>
> Radar detectors illegal?
>
> In the US, you can own and operate any sort of receiver you desire, no
> problem.  Federal law.  (Just don't key the mike unless you are licensed in
> some manner.)
>
> Some states, such as Virginia, think they don't have to obey the FCC on
> that one.  If I were still there, I'd almost like to take it to the Supreme
> Court.  But I don't speed, and never owned one.
>
> Andy
>
Further erosion of our rights, Andy.  Virginia is NOT the only state
to ban speed trap receivers ... and the feds ban receivers capable of
hearing the 800MHz cell phone frequencies.  Thomas Jefferson must be
turning over in his grave!
- Nick -

1999\07\29@214132 by Dennis Plunkett

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At 21:19 29/07/99 -0400, you wrote:
{Quote hidden}

Yep, here we can not have K band detectors in a car
Dennis

1999\07\29@220228 by Andy Kunz

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At 09:21 PM 7/29/99 -0400, you wrote:
>Not quite, IIRC radar detectors are illegal in some states.  They aren't

The law making them illegal is illegal.

Andy

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1999\07\29@220244 by Andy Kunz

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>Further erosion of our rights, Andy.  Virginia is NOT the only state

I know.  It was the only one I'm familiar with, though.  I would still love
to press the issue, though.

>to ban speed trap receivers ... and the feds ban receivers capable of

They only banned manufacture.  They didn't do anything until the Newt got
caught that time on one.

>hearing the 800MHz cell phone frequencies.  Thomas Jefferson must be
>turning over in his grave!

I know.

Andy

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1999\07\29@220742 by Richard Prosser

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As I understand it over here (NZ) the radio antennas on most city traffic
lights are to allow buses and emergency services priority - the red cycle
can be delayed slightly.
I've been trying to find out more details re the frequency & codes used etc.
- but purely for academic reasons of course :-)

(The antenna length suggests approx. 150MHz but that's all I've been able to
guess so far)

Richard
> {Original Message removed}

1999\07\30@003436 by Eric Oliver

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> >
... and the feds ban receivers capable of
> hearing the 800MHz cell phone frequencies.  Thomas Jefferson must be
> turning over in his grave!
>  - Nick -

Except for their own use of course <g>.  I just finished watching "Enemy of the
State". Scary...

1999\07\30@003451 by Eric Oliver

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You know, since we've meandered quite OT <s>. I'll sorta bring back around.
I've often sat at traffic lights during heavy traffic and thought about how
adding a little intelligence to the system could help minimize traffic. But
even such a seemingly simple task can get complicated when you consider
other lights adjacent to each other. Then you would need someway of
analyzing congestion in all four directions, etc.  It would an interesting
project and after reading this thread (including what you wrote below), we
might not be that far off from AI traffic lights.

Eric

On Thursday, July 29, 1999 8:44 PM, Dennis Plunkett
[SMTP:TakeThisOuTdennisEraseMEspamspam_OUTRDD.NECA.NEC.COM.AU] wrote:
> At 11:11 30/07/99 +1000, you wrote:
> >Boy, this must be the longest thread I've seen.
> >
> >OK, some posters were talking about air traffic control, collision
avoidance
> >etc. Here's a question re traffic control.
> >
> >In Australia, Melbourne suburbs, lots of traffic lights seem to be
> synchronised
> >so that heavy traffic flow on a main road gets all green lights. I
always
> >assumed it was done with simple timers. However, I'm *told* that radar
> detectors
> >- you know those little black-box gizmos you put on your dash to defeat
the
> >police? - are set off when approaching these synched lights. ('Course
that's
> >only what I've been told. Heh! Well, I wouldn't  use illegal technology
> myself,
> >naturally ..............!)
> >
> >So, are synched traffic lights controlled with a microwave system
somehow?
{Quote hidden}

1999\07\30@005530 by paulb

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M. Adam Davis wrote:

> Not quite, IIRC radar detectors are illegal in some states.  They
> aren't allowed to pull you over if they suspect you have one, though.
>  Only if they notice it during another infraction of the law.

 That's an interesting case regarding civil rights supposedly
guaranteed by the US constitution.  Aside: this country has no provision
for civil rights in its constitution - probably what you'd expect for a
penal colony, and a maudlin discussion current, albeit intermittent, on
whether we should be a Republic, in which I have *rarely* heard civil
rights discussed despite the conmmonsense that it would be the *only*
valid reason to seek a republic!

 Anyway, as I understand it, radio receivers are a (US) Federal matter
as they are here.  State or local rulings on any form of restriction of
radio receivers, including installation of antennae and radar detectors
are automatically invalid.  Well, that's how it *should* be...

 But as you say, the FCC chooses to assert an essentially un-
constitutional ruling on 900 MHz.  Fascinating!

Dennis Plunkett wrote:

> Are, uhm NO.
> Sync traffic lights are via telephone lines (Also provides
> communications to the signal control centre)

 I think the correct answer is "No, unless it's Yes".  Whilst Telstra
was a Government monopoly, civil authorities were entitled to free
telecommunications services.  Now they charge for lines, many services
are choosing to go it cheaper and use (packet) radio links.

Also:

> Yep, here we can not have K band detectors in a car

 It appears there *may* be an exception for *licensed* K-band users,
such as myself.  I'm not sure how well it's been tried...

Eric Oliver wrote:

> I've often sat at traffic lights during heavy traffic and thought
> about how adding a little intelligence to the system could help
> minimize traffic.
...
> we might not be that far off from AI traffic lights.

 We're a very long way off indeed.  It's Politically Incorrect you see.
Current traffic control thinking says that the slower traffic is, the
safer it is.  No-one can dispute this, so any effort to speed up traffic
is PI.

 There're presently designing roundabouts to slow down traffic by
making it go round complex slalom bends, putting 50 km/h zones in
residential areas (including main thoroughfares), and they haven't used
anticipatory sensors for Green Extension on traffic lights for many
years.  Don't expect traffic to get any quicker!
--
 Cheers,
       Paul B.

1999\07\30@010822 by PJH

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Richard Prosser wrote:

> As I understand it over here (NZ) the radio antennas on most city traffic
> lights are to allow buses and emergency services priority - the red cycle
> can be delayed slightly.
> I've been trying to find out more details re the frequency & codes used etc.
> - but purely for academic reasons of course :-)

It *is* a subject of  absorbing academic exercise, I must agree!

> (The antenna length suggests approx. 150MHz but that's all I've been able to
> guess so far)

Maybe try employing a scanner? (Radio, not the image sort.) There are lists of
frequency allocations around someplace.

PJH

1999\07\30@010835 by PJH

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Dennis Plunkett wrote:

> >So, are synched traffic lights controlled with a microwave system somehow?
>
> Are, uhm NO.
> Sync traffic lights are via telephone lines (Also provides communications
> to the signal control centre) (Notticed how the "In case of faults call
> 131360 and quote this number" sign is gone?)
> This is so for the city area as it allows VIC roads to alter sequences
> during heavy traffic times.

Right, so are the suburban ones also hardwired into the 'phone system? Just
wondering why  a radar detector would be activated at traffic lights in that
case?

PJH

--
*************************************************
PETER HYNES
FAX: Int-61-3-9809 0604 NET: RemoveMEelekspamTakeThisOuTnetstra.com.au
WEB: http://www.netstra.com.au/~elek/
*************************************************

1999\07\30@015152 by Eric Smith

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Andy Kunz <supportEraseMEspam.....MONTANADESIGN.COM> wrote:
> In the US, you can own and operate any sort of receiver you desire, no
> problem.  Federal law.  (Just don't key the mike unless you are licensed in
> some manner.)

Didn't the Electronic Communications Privacy Act of 1986 (ECPA) bans
receivers that cover the 800 MHz cellular phone band?

Of course, the whole idea of banning a receiver to promote privacy is a
travesty.  They should have required that the cellular companies either
(1) implement strong security in the communications, or (2) notify their
customers that their communications are insecure.  Or both!  Legislating that
communication is secure is about as useful as legislating that pi equals
three [*], or passing a resolution that the Boston Strangler was a
compassionate gentleman [**].

Eric

[*] Nearly passed in 1897 by the Indiana State Legislature as House Bill #246
   http://www.cs.unb.ca/~alopez-o/math-faq/node45.html

[**] Texas House of Representatives,
   http://www.urbanlegends.com/politics/boston_strangler.html

1999\07\30@033222 by Gabriel Gonzalez

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I believe they already are AI controlled, or then how would you explain
that, when it's green and you're about to arrive at the intersection it
changes to red before you can cross it, especially when you're going fast!
<G>

Gabriel

{Original Message removed}

1999\07\30@115630 by Andy Kunz

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>  We're a very long way off indeed.  It's Politically Incorrect you see.
>Current traffic control thinking says that the slower traffic is, the
>safer it is.  No-one can dispute this, so any effort to speed up traffic
>is PI.

The other thing is the slow traffic in commercial zones increases traffic
through the stores.  So the merchants actually WANT the slow traffic.

Andy

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1999\07\30@141547 by John Pfaff

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Don't try taking one into Canada either.

-----Original Message-----
From: Andy Kunz <RemoveMEsupportspam_OUTspamKILLspamMONTANADESIGN.COM>
To: RemoveMEPICLISTTakeThisOuTspamspamMITVMA.MIT.EDU <EraseMEPICLISTspamspamspamBeGoneMITVMA.MIT.EDU>
Date: Thursday, July 29, 1999 9:20 PM
Subject: Re: Traffic Lights (Was Car LED lighting etc ...)


>only what I've been told. Heh! Well, I wouldn't  use illegal technology
myself,
>naturally ..............!)

Radar detectors illegal?

In the US, you can own and operate any sort of receiver you desire, no
problem.  Federal law.  (Just don't key the mike unless you are licensed in
some manner.)

Some states, such as Virginia, think they don't have to obey the FCC on
that one.  If I were still there, I'd almost like to take it to the Supreme
Court.  But I don't speed, and never owned one.

Andy

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1999\07\30@141753 by John Pfaff

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I passed a bus once that had a sign on the back stating that it was equipped
with radar emitting equipment for the sole purpose of setting off radar
detectors.

{Original Message removed}

1999\07\30@184533 by Wagner Lipnharski

picon face
[snip]
> even such a seemingly simple task can get complicated when you consider
> other lights adjacent to each other. Then you would need someway of
> analyzing congestion in all four directions, etc.  It would an interesting
> project and after reading this thread (including what you wrote below), we
> might not be that far off from AI traffic lights.

I have a friend that works with a math system dedicated to this kind of
situation, is not that difficult, it uses lots of statistics and
priorities.  In real, the system has all the time in the world to take
care of a lazy flow system... the word is "pacing"... some of them use
electromagnetic sensors in the asphalt to count and feel vehicles
movement, other just use statistics and synchronization... my own words
about this? None of them works right!

Want to see a complete mess?  Track down the complete crazy tail a
Firetruck create behind it after opening (at its control) all the green
lights in its way... breaking all the sensible statistic traffic
flow...  It can take more than 10 minutes to get normal again, with
luck.

Wagner.

1999\07\31@124955 by Margo Erickson

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-----Original Message-----
From: Gabriel Gonzalez <spamBeGonetgoSTOPspamspamEraseMECHIH1.TELMEX.NET.MX>
To: KILLspamPICLISTspamBeGonespamMITVMA.MIT.EDU <EraseMEPICLISTspamEraseMEMITVMA.MIT.EDU>
Date: Friday, July 30, 1999 3:32 AM
Subject: Re: Traffic Lights (Was Car LED lighting etc ...)


>I believe they already are AI controlled, or then how would you explain
>that, when it's green and you're about to arrive at the intersection it
>changes to red before you can cross it, especially when you're going fast!


I have seen a set of smaller loops embedded in the roadway several hundred
feet before the stop light.  I figure they are either checking for advancing
traffic or possibly backed up traffic if the line should reach back that
far.

1999\07\31@131519 by paulb

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Margo Erickson wrote:

> I have seen a set of smaller loops embedded in the roadway several
> hundred feet before the stop light.  I figure they are either checking
> for advancing traffic or possibly backed up traffic if the line should
> reach back that far.

 Dead right on both counts.  But that's to what I referred in my
"Politically Incorrect" post.  The use of advance or anticipatory
sensors with an "extended green" cycle is self-evident, but policy has
in many places swung toward using lights to *slow down* traffic unless
traffic jams come to public notice.

 Consequently, here at least, very few suburban installations have this
feature nowadays.  (They *used* to though!)

 My town has just succumbed to PC.  They are at this time busily
installing "(50) Area" signs all over the place, including many of the
main four-lane (two each way) thoroughfares!  (Default limit 60 k/h)
--
 Cheers,
       Paul B.


'Traffic Lights (Was Car LED lighting etc ...)'
1999\08\01@125240 by Tom Handley
picon face
At 06:45 PM 7/30/99 -0400, Wagner Lipnharski wrote:
>[snip]
>I have a friend that works with a math system dedicated to this kind of
>situation, is not that difficult, it uses lots of statistics and
>priorities.  In real, the system has all the time in the world to take
>care of a lazy flow system... the word is "pacing"... some of them use
>electromagnetic sensors in the asphalt to count and feel vehicles
>movement, other just use statistics and synchronization... my own words
>about this? None of them works right!

  I've been at an intersection on a motorcycle where the light would not
change unless a vehicle was over the buried loop. Of course I happened to
be the first one in the queue, to the right of the loop, with a long line
of irate drivers behind me... When I finally noticed the loop, I walked
my cycle over it a couple of times to get the light to change... I kind
of feel guilty as I've designed buried loop vehicle sensors for car wash
systems back in the 70's...

  - Tom


------------------------------------------------------------------------
Tom Handley
New Age Communications
Since '75 before "New Age" and no one around here is waiting for UFOs ;-)

1999\08\02@012718 by PJH

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Tom Handley wrote:

>    I've been at an intersection on a motorcycle where the light would not
> change unless a vehicle was over the buried loop. .SNIP...... When I
> finally noticed the loop, I walked
> my cycle over it a couple of times to get the light to change...
>

Yeah, the ones around Melbourne are also buried in the bitumen. One across
the 'straight ahead' lanes and one in the 'right turn
lane' in cases where there's a red\green arrow. (Opposite to US practice, we
drive on the left.). You can tell from the scars where the surface has been
cut.

At intersections fitted with a 'red light camera' there's a sensor loop in
the middle of the intersection to bag red-light runners. Trouble is, they
also bag the poor saps who get stuck in the middle doing a right turn when it
goes amber.

Jus' wondering again .... what would the system would do if a car stopped
over one of the loops had  it's own loop mounted
underneath that was fed current pulses? Maybe look like a massive traffic
flow against the red light?

PJH

1999\08\02@022228 by Clyde Smith-Stubbs

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> Jus' wondering again .... what would the system would do if a car stopped
> over one of the loops had  it's own loop mounted
> underneath that was fed current pulses? Maybe look like a massive traffic
> flow against the red light?

I doubt the system would care much. I had a guided tour of the traffic
light control system in Brisbane some years ago (was running on HP-1000
minis, still is AFAIK) and the thing they're most interested in is
the detector occupancy, i.e. the percentage of time that something
is over the detector loop. It's a direct measure of traffic density.

Also, with the red light cameras, the way I was told they work is
that the camera is triggered if the detector becomes unoccupied while
the light is red, i.e. the standard in-lane detector is used, and it
triggers the camera if a vehicle leaves the detector during the red
light phase. Two photos are taken, one straight away, and one later to
confirm that the vehicle did actually pass through the intersection
(i.e. if you move out, then reverse back, you're ok). IOW there is
no detector in the middle of the intersection.

You will see detectors out in the intersection in some places, particularly
where there is a right turn lane, to detect cars that have moved out into
the intersection waiting for a gap.

A few more red-light cameras around here would be welcome - the number
of light-runners seems to be increasing. However the government seems
more interested in more speed cameras, I guess they raise a lot more
money.


Cheers, Clyde

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1999\08\02@032326 by brad

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Clyde Smith-Stubbs wrote:
{Quote hidden}

Over on this side of the country, they use PRESSURE sensitive pads about 3 feet
forward of the white line.
This was proved a couple of years ago, by a group of kids that used to drop
thier pants and all jump on the pad at once. Pretty funny photos.. anyway, the
pads are armed when the light goes red, and 2 photos are taken, one on contact
with the pad, and one a certain accurate interval afterwards... All the
intersections with red light cameras now have markers painted on the road,
delimiting distance, and because the two photos are accurately timed, they can
infer how fast you were going at the time.. Not used for speed prosecution but
useful to determine the circumstance of running the red light... ie sitting over
the line, versus doing double the speed limit thru the intersection :p)

Brad.......

1999\08\02@092721 by Matt Bennett

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At 08:59 PM 7/29/99 , Andy Kunz wrote:
>At 09:21 PM 7/29/99 -0400, you wrote:
>>Not quite, IIRC radar detectors are illegal in some states.  They aren't
>
>The law making them illegal is illegal.

The law making them illegal is just contradictory to the Act that
established the FCC in 1934, which just established the fact that "if it
falls on you, it is yours."  However the Congress has established the fact
that that they don't mind contradicting their own law, the case in point
being the Electronic Communications Privacy Act (ECPA) which contradicted
the 1934 law.  I believe Virginia's law has survived court challenges.  DC
also has a similar law.  Radar detectors are also banned in commercial
vehicles, another contradictory law passed by the Congress (and generally
ignored).

The law is going to be on the side of the party that has the best lawers
(cell phone companies (winners) vs. speeders, satellite companies (winners)
vs. pirates, States (winners) vs. speeders).

Matt Bennett

1999\08\02@093541 by Matt Bennett

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>> As I understand it over here (NZ) the radio antennas on most city traffic
>> lights are to allow buses and emergency services priority - the red cycle
>> can be delayed slightly.
>> I've been trying to find out more details re the frequency & codes used
etc.
>> - but purely for academic reasons of course :-)
>
>It *is* a subject of  absorbing academic exercise, I must agree!
>
>> (The antenna length suggests approx. 150MHz but that's all I've been
able to
>> guess so far)
>
>Maybe try employing a scanner? (Radio, not the image sort.) There are
lists of
>frequency allocations around someplace.

A method that I have seen used here in the US is a system that extends the
green to emergency vehicles by keying off a white strobe mounted on the
front of the vehicle.  The strobe frequency is specific (and unknown to
me).  You can spot these intersections that are suchly equipped- the
optical sensor is mounted in a horizontal tube pointed along the traffic
flow, attached to the same support that the light is connected to.  I used
to see these all over the Washington, DC area, but since I have moved to
Austin, TX, I have not noticed any.

Matt Bennett

1999\08\02@122309 by Adam Davis

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Well, you could always shunt a few hundred amps through such a loop, and destroy
the light controller.  After a few new light controllers, they might decide to
use a different method of car detection...

-Adam

PJH wrote:
{Quote hidden}

1999\08\02@130057 by Wagner Lipnharski
picon face
Here in Orlando, it works pretty well.
If the first car stops at the right position, before the perpendicular
white mark (limit to stop with red light), inside the lane limits, he
will be right over the sensor.  What happens is that bad habit drivers
just stop anywhere, over the separation white lines, ahead of the stop
position, long before the "stop here" position, and then they create
problems.  Some drivers just stop (to gain time I think) 2 to 4 meters
after the white line stop limit at red light, almost blocking the
crossing flow. Even for those they installed a sensor there, so right
now I can see two "8" shape sensors, one at the right position, another
for those that can't break and stop where civilized people stops at red
lights.

There is a logic at the traffic light computer, so there are an
evaluation about cars over sensors, and which flow is the one to receive
the green lights at that specific moment.  For example, if the crossing
traffic time is expired, the computer will first open the green lights
to who is waiting to do left turns, then will be the ones for trough
traffic. The left turn green lights will only happens IF there is some
car over the sensor, if not, it will go directly to the through traffic.

I have a complain about that sensors;  If I arrive over the left turn
sensor less than 5 seconds before it would activate the left turn green
light, and there was no other car over the sensor, the computer will not
validade my car's presence and I will need to wait for a complete turn
around in the flow, more than a minute with intense traffic.  It looks
like the computer just ignore the last 5 seconds of the sensors reading
for safety or something.

In Brazil they use an automatic system to monitor traffic activities on
the main highways around big cities, for example S‹o Paulo city (19
million people). You can see a schematic of those highways and problems,
you can even click over a specific part of it and see what heppened. It
is refreshed each 30 minutes. Just for fun take a look at:
http://200.19.93.5/internew/index1.html

Wagner


Adam Davis wrote:
{Quote hidden}

1999\08\02@165532 by Matthew Fries

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> A method that I have seen used here in the US is a system that extends the
> green to emergency vehicles by keying off a white strobe mounted on the
> front of the vehicle.  The strobe frequency is specific (and unknown to
> me).  You can spot these intersections that are suchly equipped- the
> optical sensor is mounted in a horizontal tube pointed along the traffic
> flow, attached to the same support that the light is connected to.  I used
> to see these all over the Washington, DC area, but since I have moved to
> Austin, TX, I have not noticed any.

There are 2 strobe lights atop the ambulance, and they flash 2 times each
in the course of 1 second. The pulse looks something like this:

   __    __       __    __
___|  |__|  |_____|  |__|  |___

  Left Left     Right  Right

I cannot be sure of the duty cycle, but I would bet that the receiver is
not that accurate.

Maybe it just counts the pulses in 5 seconds.

1999\08\02@174754 by Craig Lee

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Hmm.... I wonder if the sensors will respond to invisible or nearly
invisible light....

I was in a cab once where the cab driver looked both ways carefully,
then flicked his lights on and off at a certain rate.  To my surprise,
it worked!!

Probably something you wouldn't want to get caught at, but what you
can't see...

Craig

> {Original Message removed}

1999\08\02@180656 by Richard Prosser

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Also - If I had a strobe light on my bicycle (to stop people from running
into me) that "just happened" to match the required pattern, then .....
Richard
> {Original Message removed}

1999\08\02@194221 by Craig Lee

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Maybe you could get some ideas from Pee-Wee. (Sorry, couldn't resist)

{Quote hidden}

1999\08\02@221919 by Steve

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>Well, you could always shunt a few hundred amps through such a loop, and
destroy
>the light controller.  After a few new light controllers, they might decide
to
>use a different method of car detection...


I choose optical, then I'm gonna wait for a foggy night, and I'm gonna go
watch.
-Steve

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