Official Title: Effects of Red Light Camera Enforcementon Fatal Crashes in Large US Cities
Authors: Wen Hu, Anne T. McCartt, Eric R. Teoh
This is a 2011 study by the Insurance Institute for Highway Safety(IIHS) on red-light cameras in 62 cities with 2008 populations higher than 200,000. The study compares fatalities in the 14 RLC cities from 1992 to 1996 with fatalities from 2004 to 2008. They also use 48 other cities for control data. There is no listing of the 37 other cities that were excluded from this report or exactly why they were excluded. The statistics used in this analysis were collected by the IIHS and since there are no crash statistics gathered for this study there is no Distance-From-Intersection inclusion zone for crashes used. This study does not cover injury crashes or total crashes at all. The conclusions arrived upon are: "The average annual rate of fatal red light running crashes declined for both study groups, but the decline was larger for cities with red light camera enforcement programs than for cities without camera programs (35 vs. 14 percent)".
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This is a brief 18 page study, and the sources of all of the data is not specifically cited or broken down, and the reason for the selection of these specific time periods for pre and post data are never explained. Nor is it explained why there is a 7 year gap in the before and after time periods. We have never seen a RLC study with this large of a gap before. This study also relies on the unproven theory that red light cameras affect crash rates in an entire city including non-RLC intersections, even if there may be very few RLCs and they are far away from other busy intersections in the city. This study does nothing more to prove this relationship and the IIHS has been criticized by several research organizations, including the FHWA, because of this in the past, and a study by the University of Illinois last year actually disproves this theory. Since this study only looks at 14 out of 500+ communities that have red light camera systems installed, it does not contain enough data to come to a significant conclusion for all RLC programs. This study also did nothing to measure changes in traffic volume or even to count the number of red light cameras in place at the studied cities further degrading the results of this study. There is no mention of improvements in safety measures in vehicles or engineering of intersections affecting the results of this study. There also is no breakdown of the causes of the fatalities(ran red light, DUI, other impaired driving, etc...), or the number of fatalities per crash, further degrading the results. The statement that "National surveys indicate widespread support for red light cameras" in the study is unfounded, especially since all 15 times that red light cameras have been voted on by citizens in the USA, they have been voted down. The data shown in this study is not complete or significant enough to draw the stated conclusions from.
Several news organizations and researchers have found many flaws in this study. For example, the city with the highest reported drop in fatalities according to this report(Chandler, AZ) has responded that the drop was mostly due to loop expressways being built and moving vehicles off of city streets instead of red light cameras. Another point brought up is the choice of these time periods for before and after(which is never explained), According to the NHTSA the before period saw a general increase in fatal crashes while the after period saw a decrease in fatal crashes. The authors of this study work for the Insurance Institute for Highway Safety(IIHS), an organization sponsored by car insurance companies which make substantial amounts of money on RLC installations due to points being assessed on drivers licenses and higher crash rates, both of which lead to higher insurance premiums, as well as direct investment by some insurance companies in the companies that sell Red Light Camera systems themselves, so they have a very strong vested interest in presenting RLCs in a positive light and cannot be considered a neutral or impartial party on this subject.