OAKLAND (CBS/AP) — An audit shows Oakland is keeping cash from overpaid parking tickets despite a state law requiring refunds.

Motorists mistakenly paid parking tickets twice, adding to a $316,000 windfall last year alone.

READ MORE: Smash-And-Grab Thieves Hit San Jose Eastridge Mall Jewelry Store; 5 Sought

The city auditor said Oakland’s parking enforcement officers issued $22.7 million in tickets last year.

The $316,000 in overpayments came from inattentive motorists who paid twice.

READ MORE: Investigation Finds Vallejo Officer's Use of Deadly Force Not 'Reasonable'

The annual windfall was discovered as part of a larger audit of the city’s parking ticket management.

The auditor said Oakland bureaucrats have no knowledge of the requirement to reimburse overpayments.

MORE NEWS: San Francisco Lights Up GG Park Christmas Tree After Darkest Year of Pandemic

(Copyright 2012 by CBS San Francisco. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.)