Also, is shortening yellows actually making the roads safer or is it just a way to increase revenues? Seems like one likely cause of shorter yellow lights is that more people make harder stops at intersections, result in more rear-end collisions.
In many places, such as where I grew up in Ohio, the language regarding yellow lights is to "clear the intersection", and that if you are able to stop, you must not enter an intersection when presented with a yellow light. In other words, treat it like a red light, unless you absolutely cannot stop.
Of course in practice most folks will go for it if they think they can clear the intersection in time. Some may even accelerate, and having excessively long yellow lights may encourage that behavior even more, despite it being illegal.
>Some may even accelerate, and having excessively long yellow lights may encourage that behavior even more, despite it being illegal.
If you are in doubt about whether you can safely stop when the light turns yellow (and you have very little time to make that judgment), it's much safer to err on the side of running it.
The longer the yellow light is, the more likely you are to be able to correctly judge whether you can stop on time. The shorter yellow lights are in your area, the more likely you are to to slam on the brakes to avoid running the red light. Slamming on the brakes is far more dangerous than running a freshly changed red light, to say nothing of running a yellow.
I live somewhere with long yellows and it does encourage people to run the lights. It's a problem, but we are also a very bike-friendly city and long yellows give cyclists time to clear the intersection. Also, there is a delay after the red before the next right-of-way gets their green and this seems to prevent accidents (because the late-yellow/red light runners are clear before the next green).
Nevertheless, we do have some red light cameras here. One day I was stuck at an intersection with a camera, and I was waiting to turn left. I had a red left turn signal, and it suddenly stopped cycling. It was rush hour, and after three cycles with no green arrow, I called the non-emergency dispatch and told them the problem and asked the cop what I should do. She told me to take the safest course of action I thought I could. I told her that was running the red light during a break from oncoming traffic, but that I would be given a ticket for this. She said she couldn't invite me to break the law, but just do the safest thing. The legal move would have been to change lanes to the right and go straight through the intersection on a green, but this was also the most dangerous choice because of the heavy traffic flow. Thankfully the light cycle following my conversation with the cop, I got my green arrow, but it sucked to feel so helpless--knowing the safest and correct action (running the red once oncoming traffic allowed it) and knowing I would be penalized for it.
Also, is shortening yellows actually making the roads safer or is it just a way to increase revenues? Seems like one likely cause of shorter yellow lights is that more people make harder stops at intersections, result in more rear-end collisions.