This summer, West Seattleites will get a taste of what it will be like when the Alaskan Way Viaduct is eventually closed.

Interstate 5 - northbound from Spokane Street to the Interstate 90 interchange - will get major repairs this summer, according to the Washington State Department of Transportation. West Seattle drivers face lane constrictions, slower speeds and, in August, complete shutdown of the northbound lanes of that section of I-5.

The southbound lanes of the freeway also need work, though somewhat less because they carry less traffic than the northbound lanes.

Expect lane closures on that mile-long stretch of freeway in both directions at night and on some weekends as soon as this spring and continuing throughout the summer and fall.

The most intense closure will be Aug. 10 to Aug. 29, when all northbound lanes of I-5 will be shutdown 24 hours a day for 19 days.

The stretch of I-5 between Spokane Street and I-90 is built on two bridges that were constructed 40 years ago. The highway deck is a series of concrete sections, like a sidewalk. Connecting the sections end to end are steel expansion joints, which are failing. The steel cover plates increasingly detach from the joints.

I-5's road surface has deep tire ruts that collect rainwater, increasing the risk of cars hydroplaning.

The erosion of decades of heavy traffic has worn away the freeway's concrete pavement and exposed steel reinforcing bars embedded inside. Potholes add to the problems.

The expansion joints in the northbound lanes will be replaced and a new road surface laid down. The southbound joints will be repaired instead of replaced.

Although the concentrated closure is scheduled for August, drivers should be watchful for I-5 shutdowns at night and on some weekends as soon as this spring. Nighttime and weekend closures are planned through the summer and fall, depending on construction progress. The nature of the repair work requires warm, dry weather so wet or cold weather in the coming months could delay completion of the project until 2008.

Except for the 19-day shutdown in August, the state transportation department will try to keep three lanes open at all times. For a while, traffic will be restricted to two lanes.

Detour lanes will be narrowed during construction and there will be no road shoulders. Speeds will be reduced too.

Car traffic is expected to increase on alternative routes, including the Alaskan Way Viaduct.

Truck traffic will be advised to use Airport Way and East Marginal Way South. A lane of Airport Way will be temporarily dedicated to trucks and transit buses.

Interstate 405 on the Eastside also is expected to carry more traffic during the repair project.

Other alternative routes for West Seattle drivers will be First and Fourth Avenues South.