PUBLIC SAFETY FACILITY If you think you’ve paid all of your parking tickets, you might want to think again.

That’s because the Santa Monica Police Department in November discovered a computer error that rejected roughly 21,000 valid parking tickets issued as far back as 2004, meaning car owners did not receive warning notices advising them to pay their fines before they doubled.

Now, the SMPD, through ACS State and Local Solutions, which processes parking citations for the department, is sending warning notices to thousands of drivers who may have forgotten to pay their tickets or perhaps never knew they received one. Those tickets may have blown off windshields or was thrown away by a cruel passerby, said Sgt. Larry Horn, head of the Traffic Enforcement Division.

The SMPD is not charging any late fees.

“It’s like you just got the ticket yesterday,” Horn said. “This is a second chance for people to pay.”

Because of the snafu, the Daily Press estimates City Hall is missing out on roughly $840,000 in fines if one multiplies 21,000 by $40, the average cost for a violation. Expired meter tickets are $35 while parking in a permit-only block is $47.

The roughly 21,000 tickets that were rejected over the last four years represent only 2 percent of the total citations issued by parking enforcement, Horn said.

SMPD officials are investigating why the error occurred and why parking enforcement didn’t realize the mistake until November when they received a report from ACS. It could be that regular reports were sent to the Finance Department and not the SMPD, Horn said.

In the meantime, the computer filters that are most likely responsible for the error have been disabled.

Horn believes the error was caused by a difference in the way details about vehicles were entered into the system. For example, Scions are cars made by Toyota. If a parking enforcement officer issues a ticket for an expired meter and enters Scion as the make of the car, but the car was registered by the Department of Motor Vehicles as a Toyota, the computers at ACS or the SMPD would reject the ticket because the information didn’t match.

The ticket is still valid and placed on a windshield by the officer, but because it was rejected by the computers, the driver did not receive a notice demanding payment. It was left up to the driver to be responsible.

The filters, which look at license plate numbers and VIN numbers and other identifying features, are set up to ensure that tickets are issued to the right car and registered owner, Horn said. But when there are differences in the way a car is registered and identified, the computer makes assumptions and throws valid citations out.

Traffic enforcement officers must now be trained to enter information in accordance with the DMV, Horn said, and be more careful when entering data. Whether or not DMV staff enter information in accordance with set guidelines is out of the SMPD’s control.

“With all the good things that come with computers … sometimes they don’t do it right,” Horn said.

Some drivers have received their notices and at least one isn’t too happy about it. Melody Cervantes sent e-mails to City Council members and the City Manager’s Office complaining about the glitch and they way in which she was notified.

“I can’t even dispute this because I don’t remember ever getting a ticket,” said Cervantes, who received her warning letter Jan.12 for a ticket issued in 2006 for an expired meter. “Two-and-a-half years later and you expect me to remember if I paid this?”

Horn said he is working with ACS to insert a paragraph or two into the warning notices explaining the computer glitch and what is being done to fix the problem.

“I understand some people may look at this and start scratching their heads,” because they may not remember every getting a parking ticket, Horn said. “We could have done a better job of notifying people.”

Thousands more warning notices will be sent by ACS over the next few months, Horn said.

Those who receive notices can pay the fine or contest the violation.

“We’re making progress,” Horn said. “We are not getting as many kick-backs as we were three or four months ago. Now we just have to get everyone on the same page. … We’re not silly enough to believe the DMV will change to us. We have to change to them.”

kevinh@smdp.com