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Author Topic: Timers on Traffic Signals  (Read 7466 times)

KEK Inc.

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Timers on Traffic Signals
« on: May 04, 2012, 04:24:01 AM »

Edit:  Not Pedestrian Crosswalk timers.  Those are catered to pedestrians.

One of my friends recently went to China, and he told me about the road system there.  One interesting note is that most of the traffic lights have timers. 





When the light is red, the middle lamp will display a red countdown.  When the light is green, the middle lamp will display a green countdown.  The middle lamp will be yellow like normal when transitioning from green to red. 



There's also a more graphical design.  I don't think this is used anywhere yet, but it's a concept:


I think it's actually a pretty cool idea. 

China, the Philippines and Thailand use timers on traffic signals pretty extensively.  There's an older design, with a big obnoxious timer next to the light assembly.
« Last Edit: May 04, 2012, 04:43:22 PM by KEK Inc. »
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KEK Inc.

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Re: Timers on Traffic Signals
« Reply #1 on: May 04, 2012, 06:14:45 AM »

Most municipalities in the west coast have timers in the crosswalk lights now, but they're geared more for pedestrians than motorists. 
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KEK Inc.

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Re: Timers on Traffic Signals
« Reply #2 on: May 04, 2012, 06:52:14 AM »

Signal timing is relative to traffic circumstances, but I've definitely been stuck at lights for at least 70 seconds here in the U.S.  There's a whole Signal Timing Manual released by the FHWA. 

http://www.signaltiming.com/

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1995hoo

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Re: Timers on Traffic Signals
« Reply #3 on: May 04, 2012, 08:45:44 AM »

I like to use the pedestrian timers on the other street to give me a sense for when I can expect the light to turn green. I wish this country had the red/yellow combined cycle you see in much of Europe. Of course the pedestrian timer isn't a perfect substitute due to variations in the phasing at particular intersections (dedicated turn lanes, for example), but it's better than nothing.

Signal timing is relative to traffic circumstances, but I've definitely been stuck at lights for at least 70 seconds here in the U.S.  There's a whole Signal Timing Manual released by the FHWA. 

http://www.signaltiming.com/

During rush hour, if I hit the traffic light at the exit from my neighborhood right as it turns red for exiting traffic, I sit there for 2.5 minutes (around 150 seconds), more if the people on the other street block the box.
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agentsteel53

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Re: Timers on Traffic Signals
« Reply #4 on: May 04, 2012, 09:57:02 AM »

I've been advocating those timers for a while now.

there's an intersection here where I am stuck for a good 90-100 seconds to make a right turn
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mcdonaat

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Re: Timers on Traffic Signals
« Reply #5 on: May 04, 2012, 10:00:01 AM »

Timers are actually used in Baton Rouge, but usually in the pedestrian walkways. Seems like its meant for the walkers than the drivers, but I use them to determine whether to speed up through the light or stop, whichever is the safest.

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Re: Timers on Traffic Signals
« Reply #6 on: May 04, 2012, 10:06:34 AM »

It would make no sense to have people wait more than 30 seconds in Los Angeles at major intersections you'd have a huge traffic problem of course.

Wilshire at Santa Monica comes to mind as being about a minute or so.
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mcdonaat

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Re: Timers on Traffic Signals
« Reply #7 on: May 04, 2012, 10:10:06 AM »

It would make no sense to have people wait more than 30 seconds in Los Angeles at major intersections you'd have a huge traffic problem of course.

Wilshire at Santa Monica comes to mind as being about a minute or so.
You don't want lights changing too often... the twelve seconds wasted in a yellow changing between two different roads (both ways combined) could be twelve green seconds.

texaskdog

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Re: Timers on Traffic Signals
« Reply #8 on: May 04, 2012, 10:14:13 AM »

The dreadfully short green lights in Austin!
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Scott5114

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Re: Timers on Traffic Signals
« Reply #9 on: May 04, 2012, 10:32:45 AM »

These are actually prohibited by the US MUTCD for some reason that I can't recall.
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bulkyorled

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Re: Timers on Traffic Signals
« Reply #10 on: May 04, 2012, 10:38:32 AM »

It would make no sense to have people wait more than 30 seconds in Los Angeles at major intersections you'd have a huge traffic problem of course.

Wilshire at Santa Monica comes to mind as being about a minute or so.
There's 2 major streets with 2 sides to Santa Monica along with 2 sets of arrows

If you're on the south part of Santa Monica there's at least 2 other lights I can think of that do that. One being when it merges back onto the main part of Santa Monica when it crosses Moreno Dr.
But the wait there is rather pointless at times. Not sure how they'd do it, but they should set up a less wait time for certain times of the day when merging back on. Ive been through there at 3am or so and it still makes you wait an hour for it to go.:banghead:
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Re: Timers on Traffic Signals
« Reply #11 on: May 04, 2012, 01:39:26 PM »

They have them across Asia.

I guess there's a problem with a countdown to red/end of green and people rushing to get through before the change - hence the prohibition in MUTCD and the UK TSRGD.
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agentsteel53

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Re: Timers on Traffic Signals
« Reply #12 on: May 04, 2012, 02:08:10 PM »

I guess there's a problem with a countdown to red/end of green and people rushing to get through before the change - hence the prohibition in MUTCD and the UK TSRGD.

because the average coastal American (LA, New York, the like) driver doesn't already floor it on yellow?
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Central Avenue

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Re: Timers on Traffic Signals
« Reply #13 on: May 04, 2012, 04:27:09 PM »

These are actually prohibited by the US MUTCD for some reason that I can't recall.
Specifically ones directed at drivers, right? Because the pedestrian ones seem fairly common...
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KEK Inc.

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Re: Timers on Traffic Signals
« Reply #14 on: May 04, 2012, 04:45:47 PM »

They have them across Asia.

I guess there's a problem with a countdown to red/end of green and people rushing to get through before the change - hence the prohibition in MUTCD and the UK TSRGD.
The countdown is for when the green transitions to yellow. 

I can see it being abused for the red countdown, since people will be more than likely to jump the gun when there's 2 seconds left.
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PHLBOS

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Re: Timers on Traffic Signals
« Reply #15 on: May 04, 2012, 05:20:27 PM »

I wish this country had the red/yellow combined cycle you see in much of Europe.
Some older signals in eastern MA still use a steady red & yellow combo to indicate that all vehicular traffic most stop for pedestrian crossings (functions like the current WALK signal).
« Last Edit: May 04, 2012, 06:03:05 PM by PHLBOS »
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kphoger

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Re: Timers on Traffic Signals
« Reply #16 on: May 04, 2012, 05:57:02 PM »

OK, pedestrian crosswalk timers are not the same as vehicular lane timers.   :rolleyes:
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KEK Inc.

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Re: Timers on Traffic Signals
« Reply #17 on: May 04, 2012, 06:09:04 PM »

OK, pedestrian crosswalk timers are not the same as vehicular lane timers.   :rolleyes:
Thank you.
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bulkyorled

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Re: Timers on Traffic Signals
« Reply #18 on: May 04, 2012, 06:23:55 PM »

OK, pedestrian crosswalk timers are not the same as vehicular lane timers.   :rolleyes:

No kidding. But they work basically the same. It counts down, time reaches 0 and the light changes.
« Last Edit: May 04, 2012, 06:26:18 PM by bulkyorled »
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PurdueBill

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Re: Timers on Traffic Signals
« Reply #19 on: May 04, 2012, 06:35:36 PM »

That's where the walk signal timers basically function as de facto green light countdown in a lot of places.  Most of the time they are set so that they strike 0 when the light turns yellow, so if the walk signal timer is visible to traffic, then it provides the same information as a signal countdown would.  I see it a lot--people who have to have noticed this who gun it when they see the countdown is getting close enough to 0 that if they don't speed up, they will get a yellow turning to red so they make sure to get through on yellow.  (If people are watching the pedestrian signals while driving, are they watching other things?  And what if it's an odd signal setup and the light doesn't turn yellow when the timer hits 0?  Like if it turns yellow before that?)
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bulkyorled

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Re: Timers on Traffic Signals
« Reply #20 on: May 04, 2012, 06:41:13 PM »

That was pretty much what I was saying...

And just by what happens here (not talking about all places of the universe before my post gets all construed), is that all the timers get to 0 and change. I personally have never seen one that reaches 0 and the light doesnt change or it changes before 0. And honestly all it takes is a quick glance to see what the number is. You don't have to stare at it and swerve your car.
Usually the people in the front of the line see the other light reach 0 then they left off their breaks and inch forward anticipating the light is gonna change. Same goes for the driver counters or the crosswalk counters. They work the same, I don't get the problem.
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myosh_tino

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Re: Timers on Traffic Signals
« Reply #21 on: May 04, 2012, 06:53:06 PM »

OK, pedestrian crosswalk timers are not the same as vehicular lane timers.   :rolleyes:

No kidding. But they work basically the same. It counts down, time reaches 0 and the light changes.
Not always.  Many of the signals in the San Jose area have countdown pedestrian timers but not all will change when the timer reaches 0.  This is because the signals also rely on detector loops in the pavement that tells the controller to keep the light green to allow additional traffic to pass through the intersection.
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blawp

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Re: Timers on Traffic Signals
« Reply #22 on: May 04, 2012, 06:58:51 PM »

Bulky, at many intersections the timers hit zero and no light change because the loop sensors are still tripped. This is common in SoCal. Countdown timers wouldn't work here because most of the signals here are fully actuated.
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bulkyorled

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Re: Timers on Traffic Signals
« Reply #23 on: May 04, 2012, 07:16:12 PM »

Lets put it this way, Los Angeles (the city) works this way in 99% of the cases.  :banghead:
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KEK Inc.

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Re: Timers on Traffic Signals
« Reply #24 on: May 04, 2012, 08:09:10 PM »

Bulky, at many intersections the timers hit zero and no light change because the loop sensors are still tripped. This is common in SoCal. Countdown timers wouldn't work here because most of the signals here are fully actuated.

If the light relies on traffic detection, then the timer would be blank until the 10 seconds when the light WILL change.

The only thing that will alter it is an emergency vehicle or power failure. 
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