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On Dec. 2, the Washington State Department of Transportation (WSDOT) begins a six-month rehabilitation project to improve a section of State Route 99 (SR 99) through the Seattle-Tacoma International Airport (Sea-Tac) and Des Moines. The two-mile stretch is between S. 200th Street near Angle Lake and State Route 516 (SR 516) in Des Moines.

The $8.3 million project will improve pedestrian safety at the intersections by updating curb ramps to meet the (ADA) standards, and add a fresh layer of pavement to offer drivers a smoother surface.

More from WSDOT: Massive project will disrupt traffic for 3 years as crews work to repair I-5

Most of the work will take place during the evening/overnight hours when traffic is at its lightest, although drivers might see occasional daytime and weekend lane restrictions if deemed necessary by the contractors.

This project calls for overnight lane closures in both directions of SR 99, Monday through Friday, starting as early as 8 p.m. and reopening the following morning by 5 a.m. At least one lane will remain open in each direction during work hours.

The WSDOT plans to tackle curb work during the winter months. In the Spring, when the weather improves, the contractor will begin to tear up the existing pavement before resurfacing it with hot mix asphalt. This aggregate and asphalt binder is mixed in high temperatures to form a hard, strong pavement material with an average 20-year life span.

This section of SR 99/Pacific Highway is a heavily used route for drivers accessing Sea-Tac from the south with 30,000 daily travelers and was last paved in 2006, according to the WSDOT.

More on WA roads: Driver arrested for DUI after crashing semitruck on SR 16; traffic was slowed

This segment of State Route 99 was constructed in 1927, adding to the only north-to-south highway in Washington until Interstate 5 (I-5) was constructed during the mid to late 1960s.

Late-night travelers to Sea-Tac should anticipate minor backups and delays for the next six months while this project is underway.

Reminder: In early Spring 2025, the will begin its next phase between downtown Seattle and Northgate, closing up to two lanes around-the-clock for nine months.

You can read more of Nate Connors’ stories here. Follow Nate on X  and the ³ÉÈËXÕ¾ Newsradio traffic team  for more traffic updates.