Nighttime drivers on State Route 99 in SeaTac and Des Moines should plan for three weeks of weeknight lane closures starting Monday, July 28, for utility work along the newly-repaved state highway.

From 10 p.m. to 5 a.m., Monday nights through Friday mornings until mid-August, plan for northbound and southbound SR 99 lane closures between South 200th Street in SeaTac and SR 516 in Des Moines.

Local streets also will close nightly along this 2-mile corridor at the intersections with SR 99. Signed detours will guide people around construction.

During this project, contractor crews working for the Washington State Department of Transportation have updated nearly three-dozen sidewalk ramps along SR 99 to modern Americans with Disabilities Act standards.

They also repaved all lanes of the state highway along this 2-mile corridor, most recently at the SR 99 intersection with SR 516.

Utility work in this area will take roughly three weeks to complete, followed by several more weeks of overnight closures for lane striping along the state highway.

Real-time travel information is available from the WSDOT mobile app, the WSDOT Travel Center Map or by signing up for WSDOT’s email updates.