Official Title: Informational Update on Red Light Enforcement Program
Author: Roy W. Wasden, Chief of Police
This is a 2007 report by the city of Modesto on the effects of red-light cameras in the city of Modesto, California. This study shows the crash statistics of 4 RLC intersections in that city before, during and after their installation. The study does not define a pre-RLC and post-RLC time period. The statistics used in this analysis are from the Modesto Police Department and the study does not define if they used a standard Distance-From-Intersection inclusion zone for crashes. This study does not use any control intersections. There are no data or conclusions in this report that suggest a reduction or increase in fatalities due to RLCs. The study concludes that: "The program’s success or failure cannot be judged by these stats alone because the red light camera at each intersection only monitors one approach", and "In comparing collisions with the collision injuries, the numbers indicate that in all four intersections the likelihood that someone was injured in a collision decreased."
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This is a brief 5 page report. The data is not detailed in a way to allow for any significant before and after statistical analysis since there are no results shown(or able to be calculated from the supplied data) that show an increase or decrease in crashes after RLCs were installed because they were installed mid-year in 2005 and only full year totals are given, resulting in a full one year gap in the gathered data, and only 12 months of before and after data. If the data had been broken down by month, then a much more authoritative analysis could have been done. The selection of 4 RLC intersections is very small for this kind of study and further diminishes the usefulness of any results from this report. Just taking the first year(pre-RLC) and comparing it to the last year(post-RLC) there was a 5% decrease in overall crashes at RLC intersections, but almost a 19% increase in injury crashes at RLC intersections. The conclusion of a reduced likelihood of injury in a collision is contradicted by the data supplied.