The timing of traffic signal phasing is determined by local traffic engineers through careful study of intersections and with the assistance of nationally recognized guidelines. Where red light safety cameras are employed, they are connected to the traffic signal controller and two sensors that are buried in the pavement before the stop line or crosswalk.
The safety cameras only photograph the vehicle entering the intersection after the light has turned red. A second photograph is taken as the vehicle progresses through the intersection. Drivers who enter an intersection on a yellow light and are still in the intersection when the light changes to red are not photographed. The technology is intended to record motorists as they intentionally enter an intersection after the signal turns red. The camera records the date, time, lane number, location and speed of the vehicle. The camera produces a clear image of the rear license plate under a wide range of light and weather conditions.
This information is included on the Notice of Violation and then evaluated by sworn members of the Police Department to determine whether it should be mailed to the registered owner of the vehicle.