The District plans to open more than 11 miles of new bus-priority lanes in July, which should speed up rush-hour commuting for some Northern Virginia Metrobus riders, but also may slow down Virginia car commuters driving over Key Bridge and through Georgetown.

The new bus lanes, all outside Washington's downtown business district, are part of the D.C. Transportation Department's plan to improve area mass transit and lessen dependence on commuting by car - the largest source of air pollution in the Nation's Capital.

The major impact of the additional bus will be upon District and suburban Maryland residents. Their opening is timed to coincide with the July 1st Metro subway expansion into both Virginia and Maryland suburbs.

Almost 5.5 miles of the new bus lanes will be established along both sides of Wisconsin Avenue NW, from the Montgomery County line to Calvert Street. Other major sections will include almost 2 miles along upper 16th Street NW, 2.5 miles in Anacostia half-mile section on the east-bound side of M Street in Georgetown, from Key Bridge to 29th Street, where Pennsylvania Avenue begins.

"We may hear some screams about some of the new priority bus lanes," especially those in Georgetown and along Wisconsin Avenue NW, said Anthony Rachal, chief of mass transit for the city's transportation department. But Rachal said the new bus lanes, added to the city's 27 miles of existing bus lanes, should significantly speed up bus travel and be a further inducement for auto commuters to switch to public transit.

In a major study of Washington's main commuter routes last year, D.C. transportation officials found that bus travel actually was slower than automobile commuting during rush hours along most routes, even those with priority bus lanes. Much of the delay along each route was caused by illegally parked cars and by auto commuters illegally driving in priority bus lanes, the study found. It blamed poor police enforcement for a good part of the daily bus delays along bus-lane routes.

"Nobody's enforcing the bus lanes anywhere, except occasionally in Virginia, and what enforcement ther eis is extremely erratic," said Metro's senior bus operations specialist, Ray Russell.

Virginia State Police patrol the Washington area's longest, fastest and most popular bus lanes, on 1-95 from beyond the Beltway to the 14th Street Bridge, and Arlington police have been the Washington area's most vigorous enforcers of bus lanes, issuing an average of 270-300 tickets a month for violations of the county's two large bus-lane routes, along Wilson and Arlington Boulevards, according to Lt. John Rouse, who heads the police special operations division.

Alexandria police have spasmodically enforced the city's short but heavily travelled northbound bus-lane route on Washington Street and on Abingdon Drive, the George Washington Memorial Parkway service road which funnels much of Old Town Alexandria's traffic onto the parkway just south of National Airport.

The District's new priority bus lanes, which will be opened to coincide with the July 1st Metro subway expansion into Virginia and Maryland suburbs, were the subject of a public hearing last year but were generally ignored in the hullabaloo over over other downtown Washington, which city officials have now abandoned.

The downtown plan called for making 15th Street one way south as it passes across the Mall and by the Washington Monument and making much of downtown 14th Street one way north. The plan was opposed by the National Park Service and many other groups, and city officials are now working on a new downtown traffic plan which is expected to make few changes in present traffic patterns on 14th and 15th Streets.

The additional priority bus lanes are expected to speed up Metrobus travel, if coupled with increased police enforcement, by about 14 per cent for local buses and as much as 24 per cent for suburban express buses, the study estimates.

Last year's study found buses traveling along M Street in Georgetown, most of them coming from Arlington over Key Bridge, were averaging only 8.5 miles an hour in morning rush-hour traffic, compared to 13.6 mph for automobile commuters. During the evening rush-hour buses have a priority bus lane on the north side of M Street and Metrobuses average 11.6 mph compared to 12 mph for car commuters, even with lax police enforcement, the study found. The proposed eastbound bus lane should at least equalize the morning travel times for buses and cars, beginning in July.

The new bus lanes presently are being reviewed by Mayor Walter E. Washington and also must be approved by the Environmental Protection Agency, to insure they do not offend the air-quality plan for the District. However, both the mayor and EPA previously have supported the new bus lanes, says Rachal.