Efficacy of Red Light Camera Enforcement
Several studies of red light cameras found their use tended to reduce the number of front-into-side, or right angle crashes, but increase the number of rear-end crashes, possibly because drivers aware of the cameras would brake suddenly to avoid driving through the red light. However, despite the increase in rear-end crashes, some of these studies still found that red light camera enforcement resulted in an economic benefit because the property damage and injuries caused by right-angle crashes tended to be more severe than that caused by rear-end crashes.
Federal Study.
A comprehensive 2005 FHWA study examined red light camera programs in El Cajon, San Diego, and San Francisco, California; Howard and Montgomery counties and Baltimore, Maryland; and Charlotte, North Carolina. The study found a 25% decrease in right-angle crashes and a 16% reduction in those crashes resulting in an injury where cameras were used, but also found a 15% increase in rear-end crashes, with a 24% increase in such crashes causing an injury. Further analysis showed that right-angle crashes appeared slightly more severe in two of the seven jurisdictions but not in the other five. Even so, the report found, there would still be positive economic benefits from the use of red light cameras. The report (http: //tfhrc. gov/safety/pubs/05049/index. htm) also found that red light cameras would be most beneficial at sites where there are relatively few rear end crashes and many right-angle ones.
Virginia Study.
A Virginia Transportation Research Council evaluation of red light enforcement programs in that state found that they contributed to a definite increase in rear-end crashes, a possible decrease in right-angle crashes, a net decrease in injury crashes attributable to red light running, and an increase in total injury crashes. “Therefore,” it found, “cameras are leading to a net improvement in safety if, as might be expected, the severity of the eliminated red light running crashes was greater than that of the induced rear-end crashes. ” The study called for a more detailed analysis to determine if the crashes that were prevented would have been more likely to cause severe injuries than rear-end crashes (http: //www. thenewspaper. com/rlc/docs/05-vdot. pdf).
IIHS Studies.
An IIHS evaluation of a red light camera program in Oxnard, California, published in 1999, found that camera enforcement reduced the red light violation rate by about 42%. Increases in compliance were not restricted to the camera sites, but occurred at other intersections as well (http: //76. 12. 31. 254/rlc/docs/armey/99oxnard. pdf). Another Oxnard study, published in 2002, showed a significant citywide reduction in intersection crashes, with crashes reduced by 7% and crashes where an injury occurred reduced by 29%; right-angle crashes were reduced by 32%, while right-angle crashes involving injuries were reduced by 68% (http: //ajph. aphapublications. org/cgi/reprint/92/11/1822).
EFFICACY OF SPEED CAMERA ENFORCEMENT
Evaluation of Montgomery County, Maryland's Safe Speed Program
Montgomery Country, Maryland began its Safe Speed program in 2006. It uses speed cameras to photograph vehicles traveling 11 or more miles above the speed limit on residential streets or school zones with a speed limit of 35 mph. A September, 2009 study by the county's Office of Legislative Oversight found, among other things, that:
● the number of monthly citations decreased by an average of 78% from the program's first full month compared to the same month in the following year;
● of the half-million vehicles identified on camera over a two-year period, about two-thirds received only one citation, indicating that the accompanying $ 40 fine deterred most drivers from speeding again;
● average speed where there were speed cameras declined by about 6% one year after the program began;
● after one year of enforcement, the percentage of vehicles exceeding the speed limit when passing camera sites was cut in half; and
● total reported collisions within one-half mile of the camera sites decreased by 28% in the year after the program began; collisions involving an injury or fatality declined by 39%.
The complete report can be found at http: //www. montgomerycountymd
