Official Title: Red Light Camera Programs
Author: ELAINE M. HOWLE, State Auditor
This is a 2002 report by the California State Auditor, Bureau of State Audits on the effects of red-light cameras installed in 7 out of 20 communities in the state of California. This report compares the before and after crash statistics of 72 of the 138 RLC intersections in that state. The report uses 19 to 77 months of pre-RLC crash data compared to 4 to 62 months of post-RLC data. The statistics used in this analysis are from the Statewide Integrated Traffic Records System (SWITRS), produced by the California Highway Patrol (CHP) which defines that they use 200 feet as their Distance-From-Intersection inclusion zone for crashes, although inconsistency in reporting is mentioned as an issue for this data. There are no data or conclusions in this report that suggest a reduction or increase in fatalities due to RLCs. This report does not cover injury crashes. The results show that "Although They Have Contributed to a Reduction in Accidents, Operational Weaknesses Exist at the Local Level".
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This is a detailed 115 page report, the data is selectively chosen, only 7 communities out of the 20 communities that they have data for are used in the analysis(no reason is given for excluding 13 communities from the report), and the report only actually shows data from 6 of the 7 communities that it says are used to generate the results, because that one community apparently had no post-RLC data, which leads to the question of why it was selected for inclusion in this report in the first place. Out of those 6 communities where crash data is actually shown, not all of the RLC intersections data is used(no reason is given for these omissions). All of these selective omissions severely affect the validity of the analysis and the conclusions reached in this report. The selection of 72 RLC intersections is far above average for this kind of report, but the fact that these intersections are only a selective subset of the total data collected negatively impacts this report. The use of crash data at intersections with as few as 4 months of post-RLC data also diminishes the usefulness of this report. The conclusions of this report are somewhat supported by the limited selective data supplied.
It is important to also mention that all of the data used in this report is over 9 years old, and many changes have taken place to the RLC programs in the state of California, including changing technology as well as the fees for violations being greatly increased. One very interesting fact shown in this report is that the vast majority of RLC violations occurred within 1 second of the light turning red, with all but one community showing more than 70% of violations occurring within 1 second, and 4 out of 7 showing greater than 80%.