There were more accidents after red light cameras were installed in Suffolk County, New York, according to a report released by the city last week. Researchers found intersections had been much safer before the arrival of red light cameras.

"The number of total crashes at the 100 active red light camera locations increased by 59.6 percent, from 3515 to 5612, between the two study periods examined in this study," the report concluded.

Suffolk began using automated ticketing machines in 2009, and now a private company operates the devices at 100 intersections. The study reviewed crashes at these locations in the before period of 2007 to 2009 and compared them with the after period of 2015 to 2017. The study also looked at an extra eighteen camera intersections that were in use from 2010 to 2013, but were removed by 2015 to 2017, allowing an extra comparison of "deactivated" locations during the after period. The study analyzed a total of 13,365 crash reports in which relevant accidents were defined as those happening within 200 feet of the centerpoint of the intersection.

Countywide, accidents jumped 12 percent from the before period to the after period at all intersections, outstripping the 2.7 percent growth in county population. The analysis used this figure to adjust camera intersection performance as increasing the total number of accidents by 42 percent over what happened at camera-free locations.

The study's authors highlighted a projected reduction in fatal and injury crashes at camera intersections as evidence that the cameras were worth keeping. The actual number of fatalities, however, was unchanged, and the study admitted "there is no definitive way to prove causality."

"Since fatal crashes are rare occurrences, statistical relationships and specific projections of increases or decreases in the number of fatal crashes are difficult to forecast," the report noted. "A single crash has the potential to influence any attempt at assigning trends to rates of fatal crash occurence of any but the most general kind."

Fifteen individual photo enforced intersections did see higher fatal and injury accidents during the after period. Researchers looked closely at each intersection and were unable to come up for an explanation for the departure from the overall accident trend, except for two locations where increased development increased traffic.

Given the results, the study called for a continuation of the red light camera program. In 2017, Suffolk County Legislators Rob Trotta (R-Fort Salonga) pointed to the massive increase in rear end and total collisions and blasted the county government for rigging data to favor continuation of the camera program.

A copy of the full report is available in a 4mb PDF file at the source link below.