1. A method for enforcing traffic signal compliance, the method comprising: receiving video data from a camera; defining a target area in the received video data; identifying motion vectors in the video data; associating a cluster of the motion vectors with a vehicle; tracking a position of the vehicle across two or more video frames; using the tracking results, determining whether the vehicle stops in the target area; and, for the vehicle being determined as not stopping, signaling an occurrence of noncompliance.