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 Tennessee, the use of speed enforcement cameras, also known as traffic cameras, is regulated by state law. Tennessee Code Annotated § 55-8-198 establishes the guidelines for the use of these cameras. The law permits the use of speed cameras in school zones when the warning lights are flashing and in construction zones when workers are present. However, the law prohibits issuing tickets solely based on the evidence from a camera unless the vehicle is going at least 10 miles per hour over the speed limit in a school zone or 15 miles per hour over in a construction zone. Additionally, tickets from speed cameras must be mailed to the owner of the vehicle within 20 days of the violation, and the fine for a first-time offense is capped. The law also requires signs to be posted within certain distances of the camera to alert drivers of the camera's presence. It's important to note that the use of these cameras and the issuance of citations must comply with all applicable laws and regulations, including calibration and operation by trained personnel.