Thought this was interesting: a traffic signal with a red light "progress bar" that cycles around the light itself until the light turns green.
A Traffic Light Augmented by Progress Bars (http://infosthetics.com/archives/2009/12/eko_a_traffic_light_with_progress_bars.html)
First thing I thought of when seeing this was that this would cause drivers to gun their engines right when the light changes, or perhaps before it changes.
It seems similar to the British red-yellow (not sure of its official name) traffic sequence. It'd be interesting to see in the field.
Be well,
Bryant
The MUTCD prohibits countdown or similar displays associated with vehicular traffic (at least for the green interval...can't find the section right now). So such a display isn't likely to be seen here in the U.S.
It is an interesting concept nonetheless. I doubt people would use it to turn off their engines and save a minimal amount of fuel, but would use it to prepare for transition to green. A logical extension would be to use a similar setup to countdown the remaining time in the green indication. It would be interesting to see any studies on this device to determine its effectiveness.
QuoteThe MUTCD prohibits countdown or similar displays associated with vehicular traffic (at least for the green interval...can't find the section right now). So such a display isn't likely to be seen here in the U.S.
Yet we commonly see countdown displays for the pedestrian signals, which are often tied to the green phase...
Countdown timers for pedestrians are common in both Europe and the Far East. I saw some countdown timers for vehicles in Indonesia and they seemed fine. The countdown also did yellow and green phases, and the numbers were in the correct colour, due to high tech LED displays (the city I was upgrading all the main highways to divided highways, and good quality modern ones at that, despite not really being needed for traffic reasons).
Countdown timers aren't like the red-amber phase in the UK - yes the amber comes on for a couple of seconds before the red changes to green, however a countdown timer gives a lot more added benefits - like knowing how long you have to wait (or whether it's worth trying to push for the green), rather than giving you slightly more time to react to changing lights.
Quote from: froggie on December 02, 2009, 08:37:14 AM
QuoteThe MUTCD prohibits countdown or similar displays associated with vehicular traffic (at least for the green interval...can't find the section right now). So such a display isn't likely to be seen here in the U.S.
Yet we commonly see countdown displays for the pedestrian signals, which are often tied to the green phase...
I think the reasoning behind prohibiting vehicular countdown displays has to do with variable duration of vehicle phases. At modern signals where detection is in place upstream from the stop line, entering a value for the "passage gap" or "vehicle extension" controller setting allows for an extension (or multiple extensions) of the green phase based on upstream actuation after the initial green time expires. The passage gap setting itself is a timer that will reset every time a vehicle is detected upstream, thus extending the amount of green time for the phase. Since upstream vehicle arrivals are not constant, it is impossible to accurately predict the amount of time remaining in the green phase until the passage gap timer expires due to lack of upstream vehicles (at which point the signal turns yellow anyway) or until the phase is extended so long that the maximum green time would be reached for the phase (at which point a vehicle countdown display could maybe count off about 5 seconds).
If a signal were running in a fixed-time mode, having a vehicle countdown timer would be feasible since all signal phases are of a known duration that does not change.
The difference with pedestrian countdown displays is that the countdown time is always constant. The MUTCD specifies that the countdown time shall start with the pedestrian clearance interval, which is typically the duration of the flashing don't walk. Most (if not all) signal controllers do not have a dynamic setting for the pedestrian clearance, so the countdown timer will use the specific value entered into the controller for that crossing. The duration of pedestrian clearance interval recommended in the MUTCD calculates the time required to negotiate the length of the crossing at an average walking speed of 4.0 feet/second (the new MUTCD proposes to mandate a 3.5 ft/s interval for this calculation, a change many traffic engineers aren't in favor of).
Another thing to mention with the pedestrian countdowns is that while the pedestrian phase typically is activated during the adjacent vehicular green phase, the two do not always begin or terminate together. Using the previous case with upstream detection and passage gap, it's possible for the pedestrian countdown to end before the adjacent vehicle phase terminates due to green extensions. Another case might be a two-stage crossing, where the vehicle phase is slightly longer but the crossing time is set to allow the pedestrian to only cross to the median.
Quote from: roadfro on December 02, 2009, 12:18:17 AM
The MUTCD prohibits countdown or similar displays associated with vehicular traffic (at least for the green interval...can't find the section right now). So such a display isn't likely to be seen here in the U.S.
It is an interesting concept nonetheless. I doubt people would use it to turn off their engines and save a minimal amount of fuel, but would use it to prepare for transition to green. A logical extension would be to use a similar setup to countdown the remaining time in the green indication. It would be interesting to see any studies on this device to determine its effectiveness.
We were given a way to indicate earlier the change to yellow, and the idiots misused it. So the MUTCD banned it.
Pennsylvania for years had signals where the yellow came on 2 seconds before the green went off. I thought it was a great idea. But idiot drivers used it to try to run the signal from farther away.
Than the idiot drivers should be the ones punished, not the rest of us. Knowing how much longer the light will be red (especially in NY, where timers are still used during the day) can be very useful for those of us that still drive standards.
Quote from: deanej on July 29, 2010, 01:56:54 PM
Than the idiot drivers should be the ones punished, not the rest of us. Knowing how much longer the light will be red (especially in NY, where timers are still used during the day) can be very useful for those of us that still drive standards.
indeed. Europe has a red-yellow phase for the last two or three seconds of red, so that people can put the clutch down and the car into gear in preparation for taking off.
Quote from: agentsteel53 on July 29, 2010, 02:27:27 PM
Quote from: deanej on July 29, 2010, 01:56:54 PM
Than the idiot drivers should be the ones punished, not the rest of us. Knowing how much longer the light will be red (especially in NY, where timers are still used during the day) can be very useful for those of us that still drive standards.
indeed. Europe has a red-yellow phase for the last two or three seconds of red, so that people can put the clutch down and the car into gear in preparation for taking off.
We used to have that. It was abolished when the first MUTCD came out. The combination is prohibited for several reasons:
- Massachusetts has already used that color combination with an entirely different meaning (scramble walk). They still use it, in violation of the MUTCD. But any such existing use of an indication prevents the adoption of a different meaning of the indication by the MUTCD.
- The MUTCD specifically prohibits any indication that tells drivers to get ready for the green.
- It uses more signal time, and often prevents phase skip. The signal controller needs to know what phase it is going to next a lot earlier. This causes some phases to be skipped when cars are waiting, because those cars arrived just before the change.
You obviously do not live in a college town. If you did, you would not be asking for the red-yellow pre-green indication. The students jump the signals anyway, often starting to go straight just before the opposing left turn signal turns green instead.
I NEVER want to see a pre-green indication. It's too dangerous here.
Quote from: Troubleshooter on July 30, 2010, 12:54:48 AM
You obviously do not live in a college town. If you did, you would not be asking for the red-yellow pre-green indication. The students jump the signals anyway, often starting to go straight just before the opposing left turn signal turns green instead.
so basically, the driver jumps the gun and drives into the intersection when it is not his turn? The addition of a red-yellow to the red should help prevent that. "hm, still red, better not go. ooh, red/yellow - better start smoking my back tires like a moron."