OAKLAND -- Oakland has made major improvements managing its parking ticket operations, but the city is failing to notify people who overpaid tickets, according to a city audit released Thursday.

The report found that in fiscal year 2010-11, the city was withholding more than $316,000 in overpaid parking tickets. In nearly one-third of the overpayments, the recipient paid double the amount of the parking ticket -- evidence that recipients inadvertently paid their tickets twice after receiving follow-up notices from the city.

State law requires the city to notify ticket recipients who overpaid by more than $15 and wait three years before pocketing unclaimed overpayments, but the audit found no evidence that Oakland was making the required notifications.

Oakland City Auditor Courtney Ruby said the city had likely kept even more overpaid ticket revenue than her audit revealed since the audit only looked at one fiscal year.

In his formal response to the audit, Assistant City Administrator Scott Johnson said the city would refund overpayments greater than $200 and implement a system to notify people who overpaid tickets.

The overpaid parking tickets in fiscal year 2010-2011 constituted about 1.4 percent of the nearly $23 million in parking ticket fines collected by the city during that period.

The audit also found that the city's ticket collection agency had failed to meet targets, costing city coffers more than $400,000 in 2010-2011.

Ruby said she initiated the audit in response to citizen complaints about dealing with their parking tickets. However, the audit showed that recent technology improvements had greatly improved efficiencies.

Customer service wait times are down, nearly all tickets are now automated and ticket recipients can now view real-time ticket information and pay their tickets online.

"I think that they've really focused on turning around the operation, and they've done it successfully," Ruby said.

Contact Matthew Artz at 510-208-6435.