Due to limited resources many states use speed enforcement cameras—also known as photo or video enforcement—to take a digital photograph or video of a vehicle (and its license plate) that violates the speed limit. The use of speed enforcement cameras to issue speeding tickets or citations (mailed to the driver) has been controversial, with claims that it violates Constitutional rights.

Laws vary from state to state and in some states speed enforcement cameras are a permitted enforcement tool; in some states they are prohibited; and in some states they are prohibited unless permitted by a local ordinance (city or town).

To measure the speed of a moving vehicle and issue speeding tickets by photo enforcement, police departments generally use photo or video radar that relies on radio signals and the Doppler Effect or photo and video LIDAR (Light Detection and Ranging) technology that relies on lasers rather than radio waves. These devices require training on their proper use and regular calibration to be accurate.

In Pennsylvania, the use of speed enforcement cameras, also known as Automated Speed Enforcement (ASE) systems, is permitted under specific circumstances. The state has authorized the use of these cameras in certain areas, particularly in active work zones on state highways and on Roosevelt Boulevard in Philadelphia. The ASE systems are designed to capture images of vehicles exceeding the speed limit by a certain threshold. Violations captured by these cameras result in fines mailed to the registered owner of the vehicle. The use of ASE is intended to improve safety by reducing speeding, especially in areas with high pedestrian traffic or where workers are present. Pennsylvania law requires that these systems are properly calibrated and maintained, and that proper signage is posted to inform drivers of the presence of speed enforcement cameras. It's important to note that the specifics of the regulations and the locations where ASE is permitted can change, so it is advisable to consult the most current Pennsylvania statutes or an attorney for the latest information.