Rush-hour traffic is expected to be delayed tomorrow at Arlington Memorial Bridge as a result of a $4.7 million resurfacing and renovation project, according to National Park Service officials.

The 170-day project, which began this weekend, is likely to cause slowdowns and backups until fall, officials said.

Two of the bridge's six lanes will be closed.

Traffic will be restricted to two lanes in each direction.

One sidewalk is to remain open.

On weekday mornings, delays also are expected on Virginia roads approaching the bridge, including the George Washington Memorial Parkway and Washington Boulevard.

In afternoons, backups are considered likely on District of Columbia streets, including Constitution Avenue NW, E Street NW and 19th Street NW.

The bridge, which crosses the Potomac River between the Lincoln Memorial and Arlington National Cemetery, is used by about 70,000 cars and buses daily.

The bridge's asphalt roadway will be repaved and deteriorating concrete replaced.

Because of the construction, officials said, a detour will be required for drivers heading for Arlington Cemetery from the northbound George Washington Parkway and Washington Boulevard.

They must exit toward westbound U.S. Rte. 50 and then turn left at a temporary ramp to get to the cemetery.