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 Missouri, the use of speed enforcement cameras, also known as automated speed enforcement (ASE) systems, has been a subject of legal scrutiny and legislative action. As of the knowledge cutoff date, Missouri does not have a statewide law that explicitly authorizes or bans the use of speed cameras. However, court decisions have impacted their use. For instance, the Missouri Supreme Court has ruled in the past that certain uses of speed cameras did not comply with state law, leading to the dismissal of tickets issued by such systems. Additionally, some local ordinances have allowed the use of speed cameras in specific municipalities, but these are subject to change and legal challenge. It is important for drivers in Missouri to be aware of the local laws in the specific area they are driving, as these can vary. An attorney can provide the most current information regarding the legality of speed enforcement cameras in a particular Missouri locale and can advise on the defense of any citations issued by such systems.