A 2002 Canadian study found an inexpensive engineering alternative to red light camera enforcement that cut the number of accident claims at selected British Columbia intersections by 15 percent. Beginning in September 1998, officials spent just $35 per intersection to apply special reflective tape to the signal backplates, a process that takes just a few minutes. The modification is designed to enhance contrast, making the signal stand out against a bright daytime sky and city lights in the evening.

Researchers examined accident claims at twenty-five locations using data from the Insurance Corporation of British Columbia which provides basic insurance for all drivers in the province. This claims data was found to be much more reliable and up-to-date than police accident numbers.

"Overall, it is estimated that the improvements to the signal head backboard will result in a 14.8 percent reduction in the total number of claims at an improved intersection," the report concluded. The results are consistent with a 1998 study that used a different statistical model to find a 24 percent reduction in accidents. A full copy of the study is available in a 628k PDF file at the source link below.