Some studies reveal that cameras watching intersections to deter drivers from running red lights may increase in rear-end collisions, an Associated Press report says. Drivers afraid of being caught a running a red light often hit the brakes and are rear-ended by a vehicle behind them. A 2002 study commissioned by San Diego found the rate of rear-end collisions increased by 37 percent after the installation of cameras. The city of Philadelphia is about to install the cameras at some intersections. Yet city officials overseeing will oversee the program discount the danger, noting that any increase in rear-end collisions will be outweighed by a decrease in right-angle collisions. Those types of collisions usually cause more serious injuries, the AP report says. Officials with the National Motorists Association are seeking to have red-light cameras banned nationwide. John Petrozza, president of Mulvihill Intelligent Control Systems Inc., which has installed such cameras in New York City, said once motorists get used to them, rear-end collisions "normalize."