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 Montana, the use of speed enforcement cameras is not permitted. Montana law specifically prohibits the use of automated enforcement, which includes both photo radar and photo lidar, for traffic control. This means that no digital photographs or videos can be used to issue speeding tickets or citations in the state. The enforcement of speed limits must be conducted by law enforcement officers who are physically present at the scene. These officers may use radar or lidar devices to measure vehicle speeds, but they must be trained in the proper use of these devices and ensure regular calibration for accuracy. The prohibition of automated traffic enforcement ensures that all citations are issued directly by an officer, which addresses some of the constitutional concerns raised by opponents of speed enforcement cameras.