A city audit shows the excess fines have gone unclaimed partly because Oakland hasn't notified people of the overpayment -- as required by state law.
The city auditor says 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. The overpaid fines are from the fiscal year 2010 to 2011.
As a result of the audit, the city is putting a refund process into place.
(The Associated Press contributed to this report)