Running a red light is illegal in all states and a ticket or citation for the infraction or offense may lead to a significant fine, demerit points on a driver’s license or driving record, and increased insurance premiums (upon conviction, guilty plea, or plea of no contest).

Due to limited resources many states use automated red-light cameras—also known as photo enforcement—to take a digital photograph of a vehicle (and its license plate) that violates the red light or traffic signal by entering the intersection and failing to stop after the light has turned red. The use of red-light cameras to issue traffic 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 red-light 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).

In Montana (MT), running a red light is considered a traffic violation and is illegal under state law. Violators can expect to receive a ticket or citation, which may result in fines, points on their driving record, and potentially higher insurance rates. However, Montana is one of the states that prohibits the use of automated red-light cameras for traffic enforcement. According to Montana Code Annotated 61-8-104, the use of these devices for issuing traffic citations is not allowed. This means that in Montana, all traffic violations, including running a red light, must be observed and cited by a law enforcement officer in person rather than through automated photo enforcement.