Given the prevalence of deaths and serious injuries caused by red-light running, more than 70 communities in 15 States and the District of Columbia are using cameras at high-risk intersections to photograph drivers who deliberately run red lights, not motorists who are inadvertently in an intersection when a signal changes to red. A red-light camera system is connected to a traffic signal and to sensors buried in pavement at a crosswalk or stoplight. The camera is triggered to photograph the license tag of any vehicle that passes over the sensors above a pre-set minimum speed and at a specified time after the signal has turned red (generally four-tenths of a second or higher). In most cases, a second photograph is taken to show the violator's vehicle in the intersection. Date, time, and speed of the vehicle are recorded. Violators are ticketed by mail. In most programs, trained officers or other government officials review every picture for vehicle information and to ensure that a violation has occurred. Usually, private companies under contract to a municipality pay the costs of installing and maintaining red-light cameras. Various studies of the effectiveness of this photo system have been conducted in a number of jurisdictions. The studies indicate that the system has significantly reduced traffic accidents at those intersections with camera systems. A spillover effect has also been observed, as traffic accidents have been reduced even at intersections without the camera system. Numerous court cases have held that automated enforcement programs are constitutional and do not inherently violate due process rights; however, technology and operating procedures must be accurate and fair.