Traffic Lights

[legsbluetrain]

Check this guy out. This lone signal is the only signal controlling this intersection.

4-Way 1.JPG

4-Way 2.JPG

4-Way 3.JPG

This signal has LEDs! Every indication on all four sides! Someone neglected the historical value of this signal! On the upside, it means they plan on keeping it around.

I don't know enough about traffic signals to know who manufactured this signal.

Where is this?

[mlgillson]

Where is this?

Toledo, IA.

[Robert_Gift]

What is a "dotted" LED and "Ball" LED?
Would ball have a LEDs facing rearward into a parabolic reflector?

Some of our LEDs are developing similar patterns of individual LEDs being out.

In China, they had a single lamp signal which changed color. [o] [o] [o]
Maybe current in one direction causes RED
Current in the other direction causes GREEN Alternating current causes perception of YELLOW
Before I got to take a picture of it, they removed that signal.

They have large LED count-down signals.
You can start coasting when you realize you will not get to the intersection before the RED cycle begins.

Quiz: Why do GREEN signals have some BLUE color in them?

[Smjh1979]

In a nutshell, ball LEDs kind of mimic the incandescents in a way by using the mirrors that are used in incandescent setups, but with just around 20 or so LEDs instead of 180-200 or more.

Dotted LEDs are just that, between 150-200 or more LEDs in a circle or circular enclosure. One of these days whenever they come in, I'll show pictures on the 102 page of what is actually inside a Safetran/Dialight FLX-4000 ball LED.

[cabman701]

They have large LED count-down signals.
You can start coasting when you realize you will not get to the intersection before the RED cycle begins.

Do you mean something like this?



If so, these have been popping up all over where I live. Most of them are programed to show 3 seconds when the light turns yellow... so if you are coming up to an intersection and can see it getting close to the 5 second mark, you can start slowing down.

It has also caused a bit of a negative effect, because some drivers use them to judge when they should speed up to make it through the intersection before the red light. They have started putting covers over some of them so they are not so visible for cars and only for pedestrians.

[Smjh1979]

For the (VERY) few that Prescott has, they work a bit differently. The lights change to yellow when the timer hits 0. Some of the time though, after the counter reads zero, the light still remains at green sometimes for another 10 seconds or so.

[cabman701]

I should re-phrase my answer a bit.

The countdown timers are mostly only on the traffic lights downtown (probably about 80 intersections). All of those intersections are set up to cycle constantly regardless of traffic flow, so that is why you can rely on the ped signals.

I think there is only 1 intersection outside of the downtown area that has them... those signals are sensor controlled and the walk signals are the push button type. Those do countdown to zero, and the light still stays green for a bit after they do (which kind of defeats the purpose, doesn't it?)

[Smjh1979]

Prescott only has about 5 intersections with those kinds of signals. Prescott Valley has none of them.

[AndrewFields]

Vehicle and pedestrian phasing don't always necessarily go hand in hand. For systems that are 'on call' (traffic-actuated systems), chances are that cars are going to take more time to clear the intersection than people walking. For fixed cycle signals (downtown and/or one-way grids), it is easier to simply have the pedestrian phase activate automatically and last the length of the vehicle green, especially if pedestrian volumes are high.

At one Washington County intersection, the countdown lasts 17 seconds from the start of the flashing hand but the signals will stay green for another 30 to 45 seconds, depending on traffic volume. If there are no cars in the detection zones when the pedestrian cycle expires, the vehicle signals will turn yellow with no delay.

[weatherdan882002]

Two intersections here in town have gotten traffic signal upgrades and pedestrian signal upgrades. As a matter of fact, when the Google car came by, the upgrade was already in progress:

http://maps.google.com/maps?f=q&source= ... 2,,0,-4.58

http://maps.google.com/maps?f=q&source= ... ,,0,-15.77

The upgrades are now complete. The second intersection has all Harmon LED lights while the first intersection has a mix of Harmon and Dialight LEDs (all red and green lights are Dialight, yellows are a mix of Dialight and Harmon). Before the upgrade, there were just buttons at the intersection that said "push and wait for green", but now as you can see, they actually have pedestrian signals. Here's a close-up of one from a different intersection:

http://maps.google.com/maps?f=q&source= ... .2,,1,5.63

Just about all newer pedestrian signals look like this. The hand and walking person are on the top while the countdown timer is on the bottom. When the lights change, the countdown timer strikes "0" and the hand stops flashing just as the traffic light changes to yellow. I kinda like that better than having the light change red as the timer completes, so it gives people who disregard the timer a chance to finish crossing.