[colonel_panic]

But what happens once people get used to the new duration of the yellow light? Do they approach it based on what they're used to from all the other yellow lights they've ever seen? Then the longest yellow light in the country is the safest one, until all the other lights are lengthened to match it.

[normalfaults]

This is actually a problem in the area this article is from. In maryland the yellow light is much shorter then in virginia, therefore maryland drivers tend to stop at yellow lights in virginia which causes lots of close stopping of drivers behind . If safety was really a concern then there would be a more narrower range of allowed yellow light duration between counties and states. As far as the speed cameras are concerned they only reduce speed for a very short distance once everyone knows where they are, its a pure profit motive.

[Evbn]

Seems like VA drivers should stop racing yellow lights, and should maintain safe following distance. Even if the driver ahead chooses to roll into a stop at a green light, drivers behind should be able to stop safely.

[bediger4000]

I always thought that the safety came from a longer period of warning until the cross-traffic started, not from a longer period to dart through the intersection on yellow.

[gknoy]

Often it's not so much that people get used to it, as that the yellow lights are often set too short to react to in time (and safely) to avoid running the light. If people have to stand on their brakes to avoid running a yellow-turning-red, it's too short.

[Evbn]

Some counties have been caught setting yellow times below the 4sec state minimum.

[Evbn]

By law, yellow means "stop if possible to stop safely". Drivers should expect the yellow light to be at least 4 seconds (legal minimum in most states). Stopping at a yellow is not a problem.