Houston Coalition Against Red Light Cameras

The following two figures are from “RED-LIGHT-RUNNING HANDBOOK: AN ENGINEER’S GUIDE TO REDUCING RED-LIGHT-RELATED CRASHES by Bonneson and Zimmerman of the Texas Transportation Institute, September 2004.

Bonneson examined 541 red light violations and this is the distribution of the number of violations over time.  This distribution is typical shows that 95% occur in less than two seconds after the light turns red. My own count of data provided by the Virginia Highway Department of some 33,546 violations shows that 85% occurred in less than two seconds.

The authors collected data on 63 right angle crashes at intersections that did not have protected left turns.  The left turn crashes are marked in red.  Since all of the signals at the camera locations have protected left turns the red bars do not pertain.  The remaining bars are with one exception distributed outside to two second mark.  So reducing the number of violations that are within the first two seconds will have little effect on the overall number of crashes.  It is known that the number of rear-end collisions increases at camera intersections so the claim of camera improved safety is not convincing.  In other words, most traffic light accidents are caused by drivers who are completely oblivious to the red light because of distractions like cell phone use, or sleepy, or are impaired by drugs or alcohol.