How could they have ticketed your car? It's preposterous. Mean. Outrageous.

The meter was broken. The sign said parking was legal. The ticket writer ignored your residential permit. The license tag must have fallen off or been stolen. Your car broke down and you were phoning for a tow truck.

But what to do? Is it worth a trip downtown and an hour's wait for a hearing? Can you afford to skip work to argue over a $15 -- or a $50 -- parking fine?

Hang in there, ticket protesters. Hidden within the District's regulatory maze is a little-known channel for challenging a citation: You don't have to show up for a hearing to fight a parking fine. You can contest it by mail.

"I didn't know that," said American Automobile Association spokesman Doug Neilson, who often has advised callers to go downtown to contest unwarranted parking tickets. But, he added, mailing a rebuttal makes sense. "It sure beats going down there and standing in line," he said. "It's a zoo down there."

The instructions printed on parking tickets say nothing about writing a letter to rebut a charge. They offer only these choices: Either "pay the fine" or "appear for a hearing at the hearing office" to contest it. Nor do the instructions provide a phone number to call for information.

The omissions have been criticized by D.C. Council members. "The information that the District gives out is limited," complained council member Nadine P. Winter, who chairs a committee that oversees parking. She is weighing proposals to revamp the tickets to list mailing in a denial as an option.

According to city officials, the law is clear. The D.C. Code says that anyone who wants to contest a ticket for a parking infraction or other nonmoving violation, such as an expired inspection sticker or missing license tag, "may answer by personal appearance or by mail."

Traffic tickets for moving violations, such as speeding or making an illegal turn, are handled differently, officials said. These may be contested only at hearings.

To challenge a parking ticket, a car owner may write a letter or fill out a form. "If a person knows how to write and has supporting evidence for his case, it's as good as being here in person," said city traffic adjudication chief James D. McWilliams. "The same examiners hear it in person or by mail."

Tickets are big business for the D.C. government, which collects $32.5 million a year in traffic fines. City officials say that 1.9 million citations are issued annually, 70 percent of them for parking violations. Each year about 120,000 drivers contest tickets, most of them by appearing for a hearing.

The District overhauled its traffic enforcement system in 1979 to remove parking and other minor offenses from the purview of the courts and turn these infractions over to hearing examiners. The move was designed to lessen the D.C. Superior Court workload and offer quicker hearings for drivers.

By mid-1979, officials said, the city had set up machinery for handling disputes over parking tickets by mail, but the District government appears to have moved relatively slowly to let motorists in on the secret. Traffic officials repeatedly balked at listing the mail-in method on the tickets.

"We did give some thought to whether we could fit anything else on the ticket," McWilliams explained. But, he said, "To add anything else was going to make it more confusing for people."

Tara Hamilton, spokeswoman for the D.C. Department of Public Works, said it is unclear whether revenues from parking fines will decrease if more drivers contest tickets by mail. "That was never a consideration. That really never had anything to do with what was printed on the back of the ticket," she said.

Last August, the Bureau of Traffic Adjudication began taking steps. It set up a counter at its E Street NW headquarters where a driver charged with a parking violation can pick up what is termed a "mail adjudication" form. The form may be filled out by a car owner who does not want to wait for a hearing.

In addition, McWilliams said, clerks have been urged to tell motorists who appear for a hearing that they can protest a parking ticket by mail. Some car owners who contact the bureau, by calling 727-5000, are told about the mail adjudication system for parking violations, McWilliams added.

As a result, the agency now gets about 2,000 letters a month, many from drivers contesting parking infractions. Some are from local residents who learned of the mail-in system by phone. Others are from out-of-town visitors who were notified by mail of outstanding parking tickets.

To a crowd of car owners waiting for hearings on a recent afternoon, the existence of the mail adjudication system came as a surprise. Some said they would have mailed responses to save time if they had known they could. Others said they probably would defend themselves more persuasively in person.

"I'm sitting down here for two hours, wasting a whole day," complained Mary B. Currie, a D.C. school counselor, adding that contesting her ticket by mail would have been quicker. She had stopped at another D.C. office to obtain proof that a parking sign was incorrect. "It's really the District's mistake."

A review of recent mail adjudication records indicated that motorists may have a reasonable chance of getting fines reduced or set aside. A Severna Park woman's $30 fine was waived when she wrote that a meter was broken. A Rockville man's fine was cut from $140 to $70 when he wrote that his son got the tickets.

Not everyone was happy with the outcome. Richard Stalls, a D.C. resident, said he had successfully challenged two recent tickets by mail, but he complained that the proceedings delayed the renewal of his car registration. "I was still a loser even though I was exonerated from both violations," he said.

Eve Kaplan, a computer specialist from Mount Rainier, said she was irked that a $20 fine was reduced to $10 instead of being nullified. "They were completely unjustified." Still, she said, she would not have contested the fine if she had to attend a hearing to do so. "I would have paid it and let it go at that."

According to city officials, an examiner may dismiss a ticket if it contains erroneous data, such as an inaccurate date, location or description of a car. Grounds for reducing or voiding fines may include unexpected breakdowns, medical emergencies, knocked-down or hidden signs and other factors, they said.

Officials offered these instructions for contesting tickets for parking and other nonmoving violations by mail:

Car owners should provide their name, address, phone number, tag number and notice of infraction number along with an explanation. Tickets should be enclosed. Responses should be mailed within 15 days to the Bureau of Traffic Adjudication, Adjudication by Mail Section, 1111 E St. NW, Room 402, Washington, D.C. 20004.

No payment is initially required if a ticket is contested. Officials said, however, that a driver whose car is towed or booted may first pay any fines and other penalties to retrieve the car and later seek a refund by challenging the allegations by mail. Traffic adjudication officials are considering several new steps, including printing a phone number on tickets to obtain information. McWilliams said a "floor manager" who can answer questions may be stationed at the bureau, where car owners often wait 45 minutes to an hour and sometimes longer for hearings.

For some drivers, McWilliams warned, mail adjudication may pose drawbacks. Some car owners fail to send in enough data, he said, and an examiner must write back to seek more evidence. Other motorists need to have their memories jogged, he said. And, he added, "Some people can't write."