An audit of Oakland's parking ticket management system revealed that the city failed to refund hundreds of thousands of dollars in overpaid parking tickets in fiscal year 2010-11 alone, according to the city auditor.

In the report released Thursday, city auditor Courtney Ruby credited Oakland with making significant improvements through a new ticket management system, but noted that the city has a history of failing to notify and reimburse citizens when they overpay parking citations.

This has amounted to about $316,000 in unreturned overpayments for the fiscal year 2010-11, the auditor found.

Parking tickets bring the city about $22 million in revenue annually, according to the auditor's report.

Ruby also noted improvements to the system, namely the switch to electronic ticket devices that has made the ticketing process more efficient and timely.

The audit recommends that the city create a ticket overpayment notification process.

The city said in a formal response it is developing a system so that it can be in compliance with state law.

In the response, the city said it will generate a monthly report and proactively refund citizens who have overpaid tickets by amounts greater than $200.

For overpaid amounts less than $200, the city credits the overpayment amount toward other citations with the same license plate number.

In cases where there are no outstanding citations, the city will "follow California government code to notify the public and process the parking ticket refund claims submitted to the city. The public will be notified annually of unclaimed parking ticket funds," city officials said in a news release this afternoon.

Assistant city administrator Scott Johnson wrote in a letter to the auditor's office on Dec. 10 that at the time of the audit, the parking division was in a transitional period, which he said created "a unique series of concurrent circumstances," which may have affected some of the auditor's findings.