Red light camera vendor American Traffic Solutions (ATS) is furious that police in Kansas City, Missouri released a report last week evaluating photo enforcement intersections without giving the company a chance to modify the data. In many cities, ATS plays a key role in authoring such studies, but in this case the Kansas City police department went its own way, arriving at conclusions consistent with other, independent research on the topic.

"The results of the study are very interesting," the Kansas City report stated. "Accidents went up at some locations and down in others without any real clear patterns."

The department performed a computer analysis to identify 2500 crash reports dating from a year before camera activation in 2009 through two years after the devices were installed. The results were narrowed to the 17 photo ticketing intersections, and officers went through each report by hand to ensure only accidents that actually happened within the intersection were counted and crashes that were clearly unrelated to the traffic signal were excluded.

"These reviews involved looking at the actual report and gathering the data," the report explained. "While this was very time consuming there just simply isn't any other way to gather the data for a project like this."

The report found the overall number of accidents increased 12 percent from before cameras were installed to the two-year average after the devices began issuing tickets. Only counting the lanes that are monitored by cameras, the increase in collisions was 29 percent. Rear end accidents increased 17 percent. Right-angle accidents dipped 4 percent.

The worst performing intersection was at 59th and 71 Highway. This high-volume location saw injury accidents surge 121 percent, mostly caused by rear-end collisions. Of those rear-enders, 87 percent happened in a lane monitored by red light cameras.

Despite the mixed safety results, the cameras over the study period issued 197,494 tickets worth $19,749,400. As a result, the city police commission ordered the police special operations division to re-write the report under the supervision of ATS.

A copy of the report is available in an 800k PDF file at the source link below.