A study by the Transportation Research Board (TRB) illustrates the lack of evidence supporting the effectiveness of red light cameras.
The TRB's National Cooperative Highway Research Program Synthesis 310, Impact of Red Light Camera Enforcement on Crash Experience-A Synthesis of Highway Practice was meant to support the use of red light cameras, but in reality it undermined the credibility of the devices. The authors attempted to support the devices by speaking of the "preponderance of evidence" that the cameras equaled safety. However, any time this was stated, the authors were honest enough to admit that none of the information was conclusive.
In the second paragraph of the summary, the study even states, "For a variety of reasons the use of automated enforcement systems has not been widespread. One relates to the lack of convincing evidence that these systems improve safety, not only at the signalized intersections where they are used, but also throughout the jurisdiction that uses them." In fact, the study shows, "Nearly every study and crash analysis reviewed had some experimental design or analysis flaw. In many cases the flaw in the analysis was because of the lack of a proper control group, which would allow a valid comparison of the observed changes..."
To view a pdf version of the study, click here.
The NMA opposes the use of red light cameras and proposes engineering solutions as the real fix for intersections with high accident rates.