Commuters using the Reno Road corridor in Northwest Washington face new traffic restrictions including a lower speed limit through much of the day that is designed to protect pupils attending two elementary schools.

The new rules were announced yesterday by James E. Clark, acting director of the D.C. Department of Transportation. Their adoption comes about two years after neighborhood residents set up picket lines along the street and one morning drove their own cars along Reno Road at reduced speeds, forcing faster cars to slow down.

Reno Road and the connecting 34th Street NW, located roughly halfway between Connecticut and Wisconsin avenues, is a favorite route for motorists traveling between Bethesda, far Northwest Washington and downtown.

The new rules provide for special school zone speed limits of 15 miles an hour during the entire period from 8:30 a.m. to 4 p.m. weekdays near Murch School, at Ellicott Street NW and Lowell School at Lowell Street NW.

The old rules provided for a 15-mile-an-hour limit only during the limited periods when children are going to and from school. The old limit during other school hours was 25 miles an hour. The D.C. Police Department has promised strong enforcement of the slower speed, the DOT announcement said.

Also starting today, the traffic light at Albemarle Street and Reno Road will flash as a four-way red from the end of each evening rush hour to the beginning of the morning rush hour. If it has the intended result of forcing all traffic to stop and thereby reduce speeds through the corridor, the use of blinking red signals will be extended to six other intersections along the route.

For the first time in the District of Columbia, the corridor will be posted with signs notifying motorists that speed limits are enforced by radar.