A University of Maryland study has concluded that turning 13th Street in Northwest Washington from a four-lane commuter road during rush hour back into a two-way street has not reduced commuter traffic in the area but merely forced motorists onto nearby streets.

The study, funded by the Highway Users Federation which opposed the change, also found that travel time and delays have increased slightly for commuters using the four-mile stretch of 13th Street between Logan Circle and Georgia Avenue.

"The changeover has failed to reduce traffic congestion, save energy or produce cleaner air" as District officials claimed it would, federation director W. W. Rankin told a meeting of the National Capital Area Transportation Federation last week. The transportation group, composed of many bus, taxi and trucking companies, local businesses and the American Automobile Association, opposes the 13th Street change and other impediments to motor vehicle travel around the Washington Area.

D.C. Department of Transportation Director Douglas Schneider, who attended the meeting, disputed the basic conclusion of the study -- which has yet to be released although Rankin has announced its conclusions.

Schneider told the group the city's own traffic surveys show that since the change went into effect Jan. 7, traffic has dropped slightly, between 250 to 500 cars during the morning rush hour in the 13th Street corridor. The corridor includes 13th, 14th and 16th Streets and Georgia Avenue.

He also questioned the validity of the study's pre-Jan. 7 traffic survey, which counted rush-hour traffic on Dec. 18 and 19, the week before Christmas when many area residents already have left on holiday. District traffic counts, made last fall, found 16,750 to 17,000 cars traveled the 13th Street corridor between 7 and 9 a.m. on weekday mornings. Recent city counts show an average of 16,500 cars now using the corridor.

But Schneider insisted the main benefit of the change has been the 50 percent reduction in traffic along 13th Street itself, a residential street where a number of houses are less than 30 feet from the roadway.

The average speed of traffic on 13th Street also has declined, to about 20 miles an hour, Schneider said. Before the change, traffic averaged about 30 miles an hour, with cars frequently clocked at speeds up to 50 and even 60 miles an hour on what in effect was a four-lane highway, Schneider told the group. The speed limit on 13th Street is 25 miles an hour.

Rankin said the study will show delays have doubled on 13th Street from two to about four an hour, and travel time on the four-mile section has increased from three to five minutes or 18 percent. Rankin also said the delays and longer driving time have increased gasoline consumption air pollution and made the 13th Street corridor more dangerous.

As to the delays for suburban car commuters, Schneider said the travel time has been increased "by only four minutes on that street. I don't think that's too much to bear . . . nor does the mayor or the city council. That's the way we feel in this community. And I don't feel that it is punitive . . . I'm not against cars, although we're not going to accomodate everyone who wants to drive into Washington, one person to a car. We simple don't have the resources to handle that."

Schneider and the District have been criticized by the two federations, the AAA and some suburban officials for allegedly making automobile commuting more difficult in order to reduce air pollution and traffic congestion in Washington and to support Metro.

The AAA Glen Lashley spoke briefly at last week's luncheon meeting, accusing Schneider of "punishing commuters, tourists and 55,000 D.C. residents" Lashley claimed must use their cars to get to work.

Lashley also charged that District roads are a disgrace, unrepaired and full of potholes. "Funds for repair of potholes and streets have suffered a 63 percent decline over the past five years, unless our figures are wrong," Lashley said. d