The entrance ramp to the southbound lanes of Interstate 83, the Jones Falls Expressway, will be closed at North Avenue for about 18 months beginning Monday.

Signs will direct drivers to the nearest southbound entrance at Eager Street. The detour will be east on North Avenue, south on St. Paul Street, then east on Eager Street to the entrance.

Some of the expressway's lanes may be temporarily closed throughout the work, which is expected to be completed by July 2004. Also, some lanes may be closed Sundays through Thursdays from 8 p.m. to 5 a.m. until January. Signs detailing the lane closures will be updated daily, said Laura Williams, spokeswoman for the city Office of Transportation.

Monday marks the beginning of the second phase of renovations to I-83. The expressway will be widened and repaved between Howard and Eager streets. Barriers and signs also will be improved.

Phase one was completed Sept. 19 at a cost of $5.2 million. It focused on the expressway north of Howard Street to Kelly Avenue. It was the city's first project using a type of asphalt that is less likely to crack because of temperature changes. Other improvements include signs that are easier to see at night and rumble strips, Williams said.