You are a commuter who parked in a two-hour zone in Washington. Every two hours, you go out and move your car to avoid getting a ticket.

It's illegal, the city's chief legal officer has ruled, and persons who practice this motorist version of hopscotch soon will find tickets cosing $5 on their windshields.

The ruling was issued by acting corporation counsel Judith W. Rogers at the request of the D.C. Department of Transportation, which administers the commuter parking ban in many of Washington's residential neighborhoods.

In such designated neighborhoods, only residents whose cars bear stickers attesting to residency may park for longer than two hours at a time.

Fred Caponiti, chief of parking optrations for the transportation department, said his civilian ticketing force has reported seeing many instances in which people who live elsewhere move their cars during the day from one space to another.

"Sometimes a commuter will come out of an office with five sets of keys and will move five cars around from space to space," Caponiti said. "Two hours later, someone else will come out with the same five keys and do it all over again."

Rogers, in her ruling, said a motorist "who reparked his car in the same area after a short interval could be presumed to (be). . . circumventing the law. . . If the total duration of parking in both spaces exceeds two hours, he has violated the regulation . . ."