D.C. Police Chief Burtell M. Jefferson assured Metro officials yesterday that the police department will continue stepped-up efforts to patrol buses.

Nicholas Roll, Metro's assistant general manager for transit services, said that Jefferson had in a telephone call, "guaranteed me that we will have greater protection from the individual police districts than we did with the special 12-man-force," Roll said.

The police department recently disbanded a special 12-man team assigned to patrol buses and reassigned those duties to the city's seven police districts. Because of that action, a group called "Concerned Bus Operators" threatened to strike the Metro-bus system at midnight Sunday.

Three drivers signed the strike-threat letter, which was addressed to Jefferson. None of the three drivers could be reached yesterday. A strike does not have the sanction of Local 689 of the Amalgamated Transit Union, which represents Metro's bus drivers. "I hope there is no strike; it would serve no useful purpose," local president George Davis said yesterday.

In their letter to Jefferson, the three drivers asked for police protection at several transfer points in the District of Columbia. Jefferson told Roll that those points "will continue to be covered" by D.C. police, Roll said.

A one-day wildcat strike, led in part by the three drivers, occurred May 18 after a female bus driver was raped. Since that time, Metro has installed radio-activated "silent alarms" on all buses and outside flashing lights on 40 buses used late at night. Other buses will be so equipped. Metro police have stepped up their on-bus efforts and many other actions have been taken.

"We have done all that's within our power to do," Roll said.