Questioning the Logic of Red Light Cameras

Here’s an excerpt from a note I received from Doug Mandell, a reader:

Today I read your article about Sam Adams looking at how to spend surplus funds and I noticed that he was looking to install red light cameras.
The issue of red light cameras and their effectiveness is not something you’ve commented on previously on Portland Transport, I think a lot of communities are waking up to the fact that they don’t do a very good job of reducing accidents, not nearly as good as lengthening the yellow light time by about a second or so.

I took the following paragraph from a Wikipedia page and posted it in the feedback section on Sam’s blog:

In May 2001 Dick Armey, then Majority Leader of the United States House of Representatives, issued a report suggesting that a more effective alternative to red light cameras would be to increase the yellow traffic light warning times. He suggested red light cameras exploited intersections where signal timing was shorter than necessary for some motorists to come to a complete stop (July 2001 U.S. House testimony). A
2004 Texas Department of Transportation study found, “crashes decrease with an increase in yellow interval duration and a reduction in speed limit.” After 1.0 second was added to the yellow signal timing at test intersections, accidents dropped by 35 to 40%. This compares with a 6.4% reduction for “area-wide officer enforcement of intersection traffic control devices… during the time of the enforcement activity”

I also asked him to take a look at the conclusions in this study:

This isn’t something that I’m particularly passionate about, I’ve noticed a few studies that have indicated that increased yellow light times drastically reduce the running of red lights, and think that if it were indeed the case the city could make the appropriate changes at these intersections without spending any of that money at all.

Doug also passed on a link to this article from Popular Mechanics that suggests our red light cameras may have increased rear-end collisions.

What do folks think?

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