increasing left-turn yellow light decreases red light running

[David99]

This is an interesting test the City of Santa Clarita did. They increase the yellow light duration on left turns by 0.5 to 1 seconds and noticed that on those intersections the red light violations went down drastically. The test also showed hat the tend wasn't just a short effect from making the change.

Here is the article: Santa Clarita to put full stop on red-light cams

 

[Rockster]

When I was learning to drive (back when dinosaurs roamed the earth), the convention in my home state of Maryland for yellow light duration was 1 second for each 10 mph of speed limit, rounded up. This, for example, resulted in a yellow light duration of 5 seconds for a 45 mph road.

It seems by my casual observation that yellow light duration has shortened in the ensuing years. There have been some reports (though I can't lay my hands on one at the moment) that this yellow light shortening is a reality and the blame lies with municipalities putting public safety second to red light camera revenues.

There's a bill in consideration in the Texas legislation right now that would abolish red light cameras. The largest opposition seems to be coming from, surprise, the red light camera manufacturers who take a cut of the profits.

 

[cpa]

Near our house many intersections have "smart" lights, allowing for up to X seconds for a left-turn arrow. During heavy traffic times, the left-turn arrow can remain green for up to 40 seconds. (I have not timed the yellow, but my guess is about 5 seconds.) When the traffic is light, the arrow will turn yellow after a one or two second lapse with no cars tripping the sensor buried beneath the pavement. If there is no oncoming traffic, the left-turn arrow stays green even through the entire cycle even though no one is turning.

The drivers here have figured this out over the years, and we still have drivers sweating the light in order not to wait through an entire traffic light cycle. And enforcement here is sketchy on red-light runners. The police and CHP seem focused on speeding and cell phone misuse. I think the reason for this is that those types of infractions are easy to prosecute with generally irrefutable evidence when the officer appears in court. Running a red light is more problematic to prove without pictures. (The light was yellow when I entered the intersection, judge, I swear!) And with traffic fines easily exceeding $350 more people are fighting them.