Three civilian ticket writers were arrested yesterday for allegedly taking bribes of $10 to $20 in exchange for not issuing tickets to motorists who had parked illegally downtown, according to D.C. police and sources.

The parking control aides were targets of a sting operation conducted for several months by police officers who posed as angry motorists, a source close to the investigation said. In each case, the officer was solicited by a ticket writer who had issued a violation notice ranging from $20 to $50, the source said.

The investigation began when a motorist came to the police department to complain about a ticket writer asking for a bribe, the source said.

Two of the suspects were arrested during morning roll call at the Bureau of Parking Service, a division of the Public Works Department, at 65 Massachusetts Ave. NW. Police identified them as Sylvester Meggison, 32, of the 4000 block of Clay Place NE, and Michael Green, 32, of the 1200 block of Delaware Avenue SE. Green also had an outstanding arrest warrant for "prison breach," or fleeing a penal facility, police said.

Rosemary Stevenson, 32, of the 1200 block of Green Street SE, was arrested at home, police said.

Officers from the police internal affairs unit, which investigates wrongdoing by District government employees, made the arrests, police said. They had the cooperation of the Public Works Department.

Ticket writers enforce parking regulations, which carry fines of $20 for expired parking meters to $100 for parking on a sidewalk.

Tara Hamilton, a Public Works Department spokeswoman, said 130 ticket writers left more than 1.5 million tickets on windshields in fiscal 1989, the last year for which figures are available. She said those tickets plus the 400,000 written by D.C. police brought more than $42 million to the District treasury.

Hamilton said the only requirement for the job of parking control aide is a high school degree. Beginning pay is $15,000, which is what the three were paid, she said. She said she did not know if a security check was run on each applicant.

"They go through a great deal of training," she said. "They take classes to teach them all the {regulations} and laws and ordinances governing parking. They have to have knowledge of District streets and understand the parking signs."

Hamilton said the aides must account for each ticket they write. She said the tickets are numbered and the ticket books are checked by a supervisor at the end of each shift.

She said she doesn't know how the three who were arrested managed to bypass the system.

"This occurrence will cause us to look at where we can take new security measures," she said. "We don't want the public to think this happens often."

Hamilton said the only other arrest of a ticket writer on a bribery charge occurred a year ago.