A speed measurement system for measuring speeds of vehicles, capturing images of vehicles, and detecting violation of stop sign and traffic signal laws. The system includes a laser speed detector for determining a speed of a vehicle adjacent a stop sign. When a speed is determined, the detector generates a speed signal. The system includes a camera generally aligned with the speed detector operable to capture and store digital still images of vehicles in memory. The camera is programmed to respond to an image capture signal to generate and transmit a digital image file including a still image of the vehicle targeted by the detector. A portable processor is linked to the speed detector and the camera to first receive the speed signal, to compare the detected speed with a threshold speed, to transmit an image capture signal to the camera, and to receive the image file from the camera.