A map in Tuesday's editions showed an incorrect configuration for incoming lanes on the Theodore Roosevelt Bridge. A corrected map appears on page D2. (Published 2/25/88)

The District of Columbia government, after years of resistance, agreed yesterday to allow a fourth inbound lane to be created on the Theodore Roosevelt Memorial Bridge across the Potomac River, a $2.5 million project that is supposed to ease morning traffic jams for thousands of Virginia commuters.

Construction should begin early next year and be completed by early 1990 under the agreement reached after years of negotiations between federal, District and Northern Virginia officials and approved yesterday by Mayor Marion Barry. Officials say they anticipate minimal traffic disruption during the project.

The additional lane, which would be created without widening the bridge structure, would flow traffic directly onto the bridge from a ramp off the southbound George Washington Parkway.

The project, to be administered by the D.C. Department of Public Works, will involve narrowing the 8-foot-wide median to two feet, replacing the median with a concrete barrier and restriping the lanes, narrowing them from 12-feet wide to 11 feet, said George Schoene, traffic engineer for the D.C. Department of Public Works.

"We're not widening the bridge," Schoene said. "We will not touch the existing sidewalks on either side."

Rep. Frank R. Wolf (R-Va.), a longtime advocate of the additional lane, said it should help relieve the morning rush-hour backup on the bridge, which accepts traffic from three major feeders: the parkway, Rte. 50 and I-66.

"This is a major victory for the commuter," Wolf said. "The primary benefit will go to the people who live in Virginia and work in the District of Columbia -- it's a double winner."

Barry said through a spokesman that the agreement is "evidence of reasonable cooperation."

According to a 1986 Federal Highway Administration study, the extra lane also should increase the average morning inbound speed on the bridge from the current rate of 15 miles an hour to 33 mph.

More than 6,500 vehicles per hour cross the bridge inbound in the morning, said Edward J. Newberry, a spokesman for Wolf. The bridge carries 98,000 vehicles a day, District officials said.

District officials said they do not expect the extra lane to increase the practical capacity of the bridge because they do not plan to change the roadways or the traffic signals where bridge traffic empties onto city streets: the intersections of 23rd Street and Constitution Avenue NW and 20th and E streets NW.

The gain in average speed will result from the elimination of stop-and-go traffic at bottlenecks on the Virginia side and a reduction in lane-changing required on the bridge, said Schoene. "Between 6 and 9:30 a.m., I don't think we're going to see any increase" in the number of vehicles crossing the bridge, he said.

District officials had opposed the project for years because of concerns that the additional lane would increase traffic congestion in the city. The District dropped its opposition after concluding that another lane would reduce accidents on the bridge by reducing lane-changing, Schoene said.

"It will be a safer bridge," Schoene said, noting that District police have to respond to the accidents on the bridge. "There are fender-benders there all the time."

One key to the solution was the financing arrangement. The District has agreed to earmark $900,000 in federal interstate highway construction funds for the $2.5 million project and plans to spend $100,000 of its own money, officials said. The remaining $1.5 million was arranged by Wolf in a 1986 Transportation Department appropriations bill.

The project requires no environmental impact study, Newberry said.

One of the key area traffic issues over the years has been the number of lanes that were available to carry automobiles across the Potomac. Virginians have sought more; the District has preferred to maintain the status quo and put its transportation dollars into the Metro system.

In the 1960s, an elaborate D.C. freeway network was planned, then abandoned in the face of rigorous citizen opposition. One of the major components of that discarded plan was a Potomac crossing north of Key Bridge between Georgetown and Rosslyn that would have been known as the Three Sisters Bridge.

Construction of the bridge began, but was halted first by residents who stood in front of bulldozers, then by the U.S. Court of Appeals in 1971. There have no attempts to add bridge lanes since.