Scanning license plates to find stolen cars

I've seen SUVs with roof mounted cameras and stickers from the Insurance Bureau of Canada strolling down the lanes of Halifax and Vancouver, apparently checking license plates of parked cars against a database of stolen vehicles. Now police in Ohio are using a similar system that checks every car that enters the Ohio Turnpike. Techdirt has a pointer and a comment or two on this type of surveillance:

Techdirt:Don't Try Driving On The Ohio Turnpike In A Stolen Car:

"from the or,-um,-change-the-plates-first dept.

Beck writes 'The Ohio State Highway Patrol reports that they tested a license plate scanning system on the Ohio Turnpike last summer. The system scanned the plates of cars entering the Turnpike, and alerted the Patrol when it detected a car that was reported stolen, or was owned by a wanted fugitive. Troopers were then able to locate the car and pull it over. They say that the system identified 24 stolen cars during the test. The Highway Patrol says that the scanners only looked at lists of stolen cars and fugitives and did not access BMV records, nor did they retain a record of scanned plates.' "