Gwinnett County police this week will begin using three automatic license plate readers that were recently purchased for $20,000 each using drug forfeiture funds.

Mounted on a patrol car, the device lets officers scan up 1,800 license plates per minute, day or night. It recognizes plates from all 50 states, Canada and Mexico. It can process parked and moving vehicles for up to four lanes of traffic in any weather.

It then compares tags with millions of records, aiding police in witness identification, capturing criminals and tracking suspects.