If they didn't increase the all-red time they are making the roads more dangerous. People get accustomed to the length of the yellow & all-red time. But if the total doesn't change, only the relative proportions it shouldn't have an impact on safety.
Even worse: Red light cameras make intersections LESS safe by INCREASING accident rates:
http://www.thenewspaper.com/news/18/1835.asp
http://www.nj.com/news/index.ssf/2012/11/red-light_cameras_l...
This only makes sense since you're removing decision power from the person most qualified to make the decision (whether it's safe to stop or not).
Your other two links make a common mistake in traffic safety debates by assuming that an increase in accident rates is a decrease in safety. Look at the types of accidents that are increased or reduced by red light cameras and you'll see that they generally do make intersections safer by reducing high speed, side impact collisions. This comes at the cost of increased low speed collisions, namely people running into someone's bumper as they slam on their brakes to avoid the red light ticket which is a psychological (risk aversion) problem, not a problem with the technology itself.
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.
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.
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.
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.
This says nothing about safety leading up to the intersection (e.g. - people slamming on their brakes).
I am worried about the case where the driver, distracted, looks away from the intersection for a second. Returning their gaze to the light, they see it red. They never observed it yellow, and thus they have no idea how long it has been red and whether or not it is safe to run the light. Perhaps this is why we have yellow to begin with--as an redundant means of clocking the time until the opposing light turns green.
The counter-argument is well it increases chance of rear end collision when people stop suddenly. And that is true.
The counter-argument to the above is well they should be driving with enough assured distance between vehicles and below the speed limit.
To "maximize" revenue they could be making the legally correct assumption that everyone is keeping a good enough distance and driving below the speed limit, and they'd actually have a legally defensible position as much as I hate to admit it.
(It is also hard to argue informally that they don't know what they are doing, they know perfectly well, as others pointed out, if this was a start up maximizing revenue we should be cheering, right, right...?)
This line of discussion is unrelated to whether or not they should be trying to maximise fines.
Yellow lights increase safety by avoiding the "slam on the brakes" effect you've described. They've replaced this with a very common "floor the accelarator" reaction which also decreases safety. How do you get one without the other? Red light cameras combined with a short yellow seem the best approach to me.
In a typical car, flooring the gas pedal is conservatively going to be about 9ft/s² in the same direction as you're already moving. Slamming on the brakes is going to accelerate you at about 15ft/s² in the opposite direction as you're already moving. The effects these two actions have on safety are not comparable
>Red light cameras combined with a short yellow seem the best approach to me.
Except that that approach has been conclusively demonstrated to increase both accidents and fatalities, while lengthening yellow lights has been shown to reduce both accidents and fatalities.