The D.C. Transportation Department soon will propose a doubling of the city's minimum parking fine, making $10 the smallest penalty that would be paid by violators.

Robert Landolt, the department's general counsel, told the City Council Transporation Committee last week that a new regulation revising the level of fines has been drafter and is being readied for presentation to the council.

Under the proposal, Landolt said, such violations as overtime parking, automobile parking in truck loading zones and parking in building entrance zones would increase from $5 to $10. Parking in "no parking" zones would go from $10 to $15. Parking in bus stop zones would got from $10 to $20. Parking in front of fire hydrants would cost $25 instead of the present $15.

There would be no change in the $50 charge for towing and impounding cars.

Landolt and John Brophy, head of the department's transportation bureau, appeared before the council primarily for a review of the city's civilian parking enforcement program, which began last October.

While acknowledging flaws, Brophy said the program has generally worked well. That verdict was shared by most of a dozen citizens who testified and asked for even stronger enforcement, mainly in residential neighborhoods.

The only sharp dissent was voiced by John Kelly, who contended in testimony for the D.C. Federation of Civic Associations that the program has been unduly costly.

Landolt said the proposed higher parking fines were being considered last year by a panel of D.C. Superior Court judges, who then had control of them. But the judges decided against raising the fines because the civilian enforcement program was soon to go into effect.

Under the new procedure, the Transporation Department prepares the regulations to put the higher fees into effect, and then must submit them to the council. The council has 45 days to make changes before the regulations go into effect.

Brophy said the department's civilian ticket writers have written more tickets than expected.

At the outset, Brophy said, it was estimated that each of the 50 parking aides would write 75 to 100 tickets a day. They are averaging 108. The national average is about 75, and ticket writers in New York City average only 37 each, Brophy said.

On the other hand, Brophy said, the number of cars that are towed away each day is lower than estimated. The department had projected 450 a day, while the current daily average is about 200.

". . . We have found that on occasion, our ticket writers have authorized unnecessary tows, and citizens have been inconvenienced," Brophy said. "We find that at this [200 a day] level, we can . . . gain the transporation and safety benefits that we set out to accomplish."

Towing is authorized now only when there is a serious transporation or safety problem, Brophy said.

Brophy said more than 100 cars a day with an accumulation of unpaid tickets are being booted. On the day before the hearing, he said, 124 cars were immobilized by boots, with the drivers required to pay all fines before the cars are released.

Since the start of the program, Brophy said, 23,800 vehicles have been towed and 5,300 have been booted.

Brophy said the program was expected to produce up to $14 million in additional revenue for the city. Partly because of computer failings and other problems, he said, collections are about $3 million below what had been expected at this time. But he said much of the money would be recovered as backlogged tickets are collected.

Police Chief Burtell Jefferson, who also testified, said the shift to civilian parking enforcement has permitted his officers to pay more attention to moving violations.

"We have about doubled the number of tickets we have issued for moving violations and pedestrian violations," Jefferson said. The 16,000 moving and pedestrian violations ticket issued in May 1978 rose to 35,000 in May 1979, he said.