Most states are always in a tension between how much traffic enforcement they employ and questions of safety. Obviously, if Pennsylvania had a state police trooper stationed every couple of miles along the roads and highways, few people would speed, drive drunk or engage in other unsafe driving violations.
On the other hand, the Commonwealth would almost certainly go broke under the weight of attempting to cover the payroll costs of thousands of additional state and local police. To stretch budgetary dollars, some jurisdictions have begun to employ mechanical methods of enforcing traffic laws, like red light cameras, as a means of reducing traffic violations and car accidents.
There is no free lunch, and with red light cameras comes issues of accuracy of enforcement and due process. Since the camera is attempting to take a picture of the license plate, the identity of the driver may not be clear.
This has led to complaints by individuals regarding the process, because it may be weeks later before a ticket is processed and mailed, and a driver may recall nothing about the incident and have little recourse but to pay the fine.
This is especially true for out-of-state drivers. Few are likely to drive back and hire an attorney to dispute a ticket from a state they passed through weeks ago during a vacation or business trip.
Two legislators in New Jersey are introducing a bill that would prevent that state's residents from receiving tickets from foreign jurisdictions. This already has happened in South Dakota, due to many complaints from residents who received tickets in Iowa.
Pennsylvania has no statewide program for use of red light cameras, but some have been used in Philadelphia and Pittsburg. No word on whether any Pennsylvania legislators are considering a similar bill.
Source: The Washington Post, "New Jersey drivers may be able to ignore other states’ speed cameras," Sarah Ferris, August 4, 2014