Convergence indexing road traffic monitoring is a system of motion sensors and speed cameras placed on highway ramps. The system creates a centralized index of cars based on their license plate numbers. Drivers who repeatedly use the same ramps, especially during rush hour, may be sent a notification to use an alternative route in the future.
Criticism of convergence indexing 
Critics say that collecting a license plate database of law-abiding people is a breach of civil liberties and human rights.