Red light cameras are proven to reduce the most dangerous intersection crashes (T-bones) at the expense of a slight increase in rear-end collisions (which are the fault of the second driver for following too closely, and likely both drivers for speeding.)

Before anyone starts bleating about companies changing cycle times: that's only happened in a few areas and most municipalities and states have caught on to the scam. It's an easy legislative fix to require light timings be based off federal standards, which they should be anyway.