Red Light Cameras Save Lives

by A. Aeron-Thomas and S. Hess looked at the results of 10 studies. They found that total injury crashes fell by a significant amount in intersections that installed RLCs (estimates ranged from 13 to 29 percent). The reduction in total crashes was smaller for reasons I’m about to discuss, but it ranged from 7 to 26 percent. They concluded that RLCs reduce total casualties, though the reductions in total collisions are more modest.

Another study, this one from the Federal Highway Association, also found overall safety benefits. It concluded that right-angle crashes drop by about 25 percent when RLCs are installed. However, echoing a complaint frequently made by RLC detractors, it did find that rear-end collisions increased as drivers were more likely to slam on their brakes at the sight of a red light and get hit by the following car. Thus rear-end collisions tend to rise by about 15 percent.

However, right-angle crashes are far more dangerous and damaging than rear-enders, which explains why the study found that, on average, each RLC generated a net savings in crash costs of about $39,000 per year.


Net savings after the cost of running the cameras. I wonder what the cost is, if any, in increased commute time.

I do think that rolling right-on-red should be allowed (not punished by RLC). The risk to pedestrians crossing at the time from inattentive drivers who feel free to roll-right-on-red is terrible, though.

In general, intersections would work better if:

1. there were pedestrian-recognition sensors (would likely have to be optical; whether active like radar, or passive like regular image recognition) that signal (especially for right-on-red turners) the presence of pedestrians. most of us have a habit of consciously checking for pedestrians at intersections, but not everyone does.

2. there were omnidirectional indicators of time-until-next-change. you already almost get this with the time counted on don’t-walk signals (once you know an intersection).

3. it were legal to run a red light after stopping if there are no other cars waiting (and obviously, without interfering with any moving cross traffic). many of us have done this late at night with no ill effects.

4. car-presence sensors were more universally employed, and worked more reliably for bicycles and motorocycles (just make them properly sensitive)

5. yellow light durations were indicated in some analog fashion (progress bar)

If you ever find yourself driving in Boston it has almost become customary for you to allow the first car in the turn lane to “bang a left” in front of you before you pull forward from the light.
Not sure about that one. If that were the custom, people going straight would have to get used to a slow start (as the quote suggests). I sometimes accelerate quickly when my light turns green (but only after actually checking for red light runners and left-bangers).