WASHINGTON - A new report from the D.C. Department of Transportation finds that speed cameras are doing a good job at reducing accidents, injuries and slowing drivers down.
DDOT teamed up with engineering firm Parsons Brinckerhoff to study 295 speed camera locations within the District of Columbia. These include existing, planned and proposed locations for the cameras. According to the executive summary findings, total crashes dropped 16.83 percent and the number of injuries 20.38 percent after cameras were installed.
"Using the analysis results from the speed data analysis and the crash data analysis, as well as reviewing the field assessment results, the team was able to determine the nexus between traffic safety and the speed camera at most locations," the report finds. "Overall, all of the results supported the nexus between traffic safety and the speed cameras at all 295 existing, planned and proposed locations."
DDOT Chief Traffic Engineer James Cheeks, who co-authored the report, says the 100 block of Florida Avenue NW is a perf ect example. A camera was installed there in November 2011.
"We noticed people, prior to putting that camera there, would speed to try and go through the signals along that roadway. Now they're more cognizant of the fact that there's a park there, kids are crossing, parents are taking their children, there a lot of elderly people walking in the area. So drivers are being more cautious as they drive through that area," he says.
At each location, engineers compared the number of crashes and the overall speed of drivers to determine the safety impact. Cheeks says drivers do slow down for cameras.
"Speeds were 10 to 15 miles per hour over the speed limit. We put in cameras and we saw the speeds one to five miles over the limit," he says, although he wishes people would slow down more.
John B. Townsend II, AAA Mid-Atlantic's Manager of Public and Government Affairs, applauds DDOT's detailed analysis.
"Given what has befallen the Baltimore automated traffic enforcement programs and the speed camera program in smaller jurisdictions in Maryland, such as Fairmount Heights and Morningside, this report delves into a salient and essential rubric. The nexus between crash sites and incidents data and speed camera location, and most of all, safety for motorists, pedestrians, cyclists, motorcyclists, school children, seniors and joggers," he writes in an email to WTOP.
Townsend says he hopes people in Morningside and Fairmount Heights and other small Maryland jurisdictions will read this report and make their goal about safety, not raising revenue.
However, if you look closer at the 3500 Massachusetts Avenue NW speed camera, you'll notice mixed results bring up an issue hotly debated in automated traffic enforcement. The report finds that while drivers are now traveling much slower than the speed limit, the number of crashes have increased since the camera went up in January 2010. In particular, a spike in the number of rear-end collisions.
Critics point out that such crashes often spike at red light and speed camera locations, when drivers slow down to avoid a ticket, forcing the driver behind to slam on his breaks. The critics add that when you increase rear-end collisions, such cameras are not improving traffic safety.
However, the authors of the report did not come to the same conclusion here.
"The increase in the number of crashes after the installation of the speed camera suggest an outlier and a more detailed safety analysis is needed to determine the cause of an increase in collisions," says the report .
And yet the conclusion seems to back up the camera.
"The speed data analysis showed the mean and 85th percentile speeds to be lower than the posted speed limit, and the crash data analysis showed elevated number of speed-related crashes at this location. Due to the analysis results along with the specific site characteristics and pedestrian generators, there is a nexus between traffic safety and the speed camera at this location," the report says.
Critics also point out that while drivers slow down when passing a camera, they often just speed back up once they pass it. So while 85 percent of drivers at 3500 Massachusetts Avenue NW went 12 mph in the 30 mph zone, drivers likely sped up short after passing the camera.
Nonetheless, Cheeks thinks the camera works and hopes that the new stop sign, pedestrian and intersection cameras recently deployed will help make roads safer.
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