Maine's ALPR retention law (2013)
Maine became the first state to restrict automated license plate reader data, capping retention at 21 days and limiting who could access the records. The law followed concerns from civil liberties groups that police were building searchable databases of drivers' movements.
Maine police agencies adjusted retention practices and reporting requirements.
The law set a template other states later drew on for ALPR limits.
Missouri's 30-day cap is the same mechanism Maine pioneered over a decade ago, but imposed by executive order while awaiting legislation.
