The Technology

How Does It Work?

The PHOTOSafe program is designed to reduce the number of violations by automatically capturing evidence of vehicles whose drivers violate the law. Photo enforced signs are located within 500 feet of the intersection in an effort to remind drivers to comply with the traffic signal. The enforcement cameras are only active during the red cycle of the traffic light. Vehicles that enter the intersection after the light has turned red for .5 or ½ second are captured. The camera system is wired to the traffic lights and to sensors that are buried in the lanes of the roadway surface. Vehicles that cross the sensors after the light has turned red activate the system. The violating vehicle is photographed 3 times and a 12 second video of the violation captures the vehicle in motion. The first photo is taken at the stop bar as evidence to show that the light was red prior to the vehicle entering the intersection; the second photo is the vehicle’s license plate for identification purposes; the third photo is taken to show evidence of the vehicle proceeding through the intersection while the light is still red. The photographed documentation of the red light violation is evidence for the police department to issue a civil penalty to the owner of the vehicle.

Chesapeake Police Department PHOTOSafe Program Diagram

The diagram above is a representation of the PHOTOSafe camera systems used in the City of Chesapeake. This picture illustrates a single intersection approach with three vehicles in violation of the traffic signal. Each system contains multiple cameras that can capture multiple lane violations occurring at the same time. Drivers are reminded that our systems do capture right turn on red violations.

Automated Technology

The cameras are wired to the traffic lights using sensors that are buried in the roadway surface.

Vehicles that cross the sensors at a predetermined speed after the light has been red for .5 seconds activate the system.

The vehicle is photographed three times: (1) prior to entering the intersection; (2) close up of the vehicle license plate; and (3) after it enters the intersection.

Video Technology

The vehicle's violation is also recorded by video.

The video monitoring system uses SmartScene™technology, a subsystem for full-motion video providing situational awareness before and after incident.

The camera is constantly monitoring but only saves digital images when a vehicle initiates a video capture. Video capture saves six seconds of video prior to the violation and continues for another six seconds. The video is paired with the photographs and treated as one red light running event or violation. The capturing of video prior to the offense triggering the camera system provides the reviewing officer with discretionary information used in the process for accepting or rejecting the violation.