For those that do not believe there is ANY improvement in safety:
http://www.tfhrc.gov/safety/pubs/05048/index.htm
A study by the Institute of Transportation Engineers who have been setting standards for traffic signals since the 1930's.
Short list. The cameras increase rear-end accidents and reduce right-angle (T-bone) accidents. Because T-bones are generally more severe (and cause more deaths), the overall safety of the intersection increases (slightly fewer accidents, much less severe accidents, less repair costs, fewer medical costs).
No doubt the politicians are NOT doing this for increased safety. But safety is still benefitted.
So the study suggests it has to be cameras OR no cameras? No other solutions possible? What about increaseing the yellow light by a second or two. If the city was REALLY concerned about accidents, wounldn't that work?
The the city collects for the lawyers advertising on city benches at the intersection.