Victor Stewart issues a parking ticket while working his beat on July 27, 2011 in Washington, D.C. (Amanda Voisard/THE WASHINGTON POST)

Two steps are normally needed to use the District’s pay-by-phone parking system: Find a legal space and check in by phone. Some drivers have discovered a third: Challenge the ticket that appears on your windshield.

Parkmobile, a cashless system first available in the District in July 2010, is supposed to offer convenience, especially if you don’t have quarters. But it doesn’t always work the way it is intended.

Some citations have incorrectly claimed that time has expired, requiring the owner of the vehicle to contact Parkmobile and the D.C. government to void the tickets. The errors, which can be disputed online or in person within 120 days, are not a widespread problem, according to John Lisle, spokesman for the District Department of Transportation.

That doesn’t soothe Lindsey Jean Damon, who lives in Van Ness. Damon said she’s received a ticket every time she’s used the service. She signed up in October because she liked the ease of being able to pay by phone or with a mobile app.

“It’s a pain in the butt for me to keep quarters around,” Damon said. “I’m at the point where I pay for everything on my credit card anyway. It’s easier to use my phone, which I do keep with me all the time.”

Damon used Parkmobile in the Tenleytown and Cleveland Park neighborhoods four times from October to February, she said, and received a ticket each time. She submitted her Parkmobile receipts and citations to the Department of Motor Vehicles, which voided each ticket, Damon said.

“Someone’s dropping the ball, whether the Parkmobile service is not cooperating with the officers or whether they’re just being too lazy to check the mobile system,” Damon said. “If Parkmobile is not going to work because it’s not going to communicate with the handheld [meter] checkers, then D.C. needs to use a system that does work.”

Lisle said the problem stems from a combination of infrequent technological glitches and errors entered by people using the system.

“What we think happens is, the parking officer comes up to a car, [the meter] doesn’t show that they’ve paid ... then they check their mobile device and the handheld device communicates with the system that Parkmobile uses,” Lisle said. “If, for any reason, there’s a delay in that information showing up on the parking officer’s handheld device, then they won’t know that person has paid by phone. That’s when somebody gets a ticket.”

Before recent software upgrades, DDOT’s error rate was 0.25 percent, Lisle said. It’s since dropped to less than 0.1 percent, he added. The Department of Public Works cited a similar decrease.

Out of more than a million parking transactions completed in 2011, Parkmobile sent 2,611 contested tickets to the DMV, all of which were voided, according to Laurens Eckelboom, Parkmobile’s executive vice president of sales.

“We are aware of the fact that there are still tickets written in error and we feel very sad about that,” he said. “We want to provide a superior customer experience in everything we do. ... We take these erroneous citations very seriously.”

Lisle said if there is an issue with multiple tickets in a specific area, DDOT can check which officer is writing the tickets to determine whether the problem is related to technology or personnel.

“Thousands of people are using it every day, so obviously it’s working,” Lisle said.

Pay-by-phone parking systems have gained popularity around the region. Montgomery County offers the feature through another provider, ParkNOW! That system allows drivers to use their cellphones to scan codes on the meters that identify the parking space to the cashless system.

Parkmobile, DDOT and DPW are working on more safeguards, including software upgrades that double-check whether there has been a valid parking transaction for a particular license plate number, Eckelboom said.

For those disenchanted with the process, though, those safeguards might not be enough.

“I am all about attempting to use new technology that makes things more efficient, but I’m not going to do this again,” Damon said. “I’m just going to keep my quarters on my dashboard.”