There’s a lot of conflicting information “out there” on the results of traffic cameras. Whatever conclusions you want to support, you are sure to be able to find a study that supports that conclusion. Oak Ridge (and any other community considering cameras) needs to “proceed with caution” in making a decision.
I haven’t sorted out all of the various “pro-camera” and “anti-camera” groups. However, National Motorists Association is a consistent opponent, while Insurance Institute for Highway Safety loves traffic cameras. The research findings these two groups report and the manner of their presentations are strongly correlated with their positions on cameras.
Everybody seems to agree that there are no valid controls for any of the studies (for example, in any “before” and “after” study there are numerous other changes occurring that could influence accident rates and severities). There are suggestions that the findings reported are strongly correlated with the affiliations of the people doing the reporting (kind of like drug companies that don’t report the results of the clinical studies that did not find favorable results).
There even seem to be some full-blown conspiracy theories about red light cameras — I’ve seen allegations that one Insurance Institute for Highway Safety staff member is working with traffic engineering professional organizations, vendors, and possibly local governments to “sell” red-light cameras. One allegation is that standards for yellow-light durations have been so as to increase the number of redlight violations, thus creating a profitable market in stopping violations. Former U.S. House of Representatives Majority Leader Dick Armey sponsored some sort of Congressional investigation that found that since 1985, yellow traffic light timing had been cut “from an average of five seconds to three seconds in duration” (at the recommendation of traffic engineering organizations) and alleged that “revenue collected from intersections with these shorter durations have become a mainstay of many local governments.” (See this article on the National Motorists Association website).
One of the conspiracy-theorist charges that I don’t believe is true is the allegation that these are a big source of cash for local governments. The main money issue with these systems is that they are expensive to set up and maintain. As a result, they don’t get used except in locations where they are expected to generate a lot of revenue from tickets, and most of the ticket revenue goes to pay for the system (including both money for the vendor and local costs for operation). In many jurisdictions, ticket revenue is less than the cost of the system. Indeed, yesterday an Oak Ridge resident alerted city officials to an interesting article that discusses jurisdictions that have shut off their cameras due to declining revenues.
Added March 29th: Over at AtomicCityTalk.com, Ray Evans posted a link to Federal Highway Administration Red Light Camera Systems Operational Guidelines, which is presumably a neutral source and has comprehensive practical information on the whole topic.