Construction is expected to start this month in Kent to complete the unfinished extension of State Route 509 to connect to Interstate 5.

Work on the initial four-year project to connect to 24th Avenue South in SeaTac will start at the I-5/State Route 516 interchange in Kent, according to a Nov. 12 Washington State Department of Transportation (WSDOT) news release. Improvements to this busy interchange include extending nearby Veterans Drive to create a new connection to I-5 and the future SR 509 Expressway.

These improvements will ease traffic congestion to and from the Kent Valley, according to WSDOT.

The four-year project includes:

• Reconstructing the I-5/SR 516 interchange in Kent, with improved access to transit

• Extending Veterans Drive under I-5 in Kent to connect to I-5 and the future SR 509 Expressway

• Building the first section of SR 509 Expressway between I-5 and 24th Avenue South in SeaTac

• Constructing a new South 216th Street bridge with bike lanes and sidewalks over I-5 between SeaTac and Des Moines

• Building new ramps that connect I-5 to a new SR 509 Expressway

The new Veterans Drive undercrossing of I-5 and extension will provide a relief valve for drivers going to and from the Kent Valley, as it includes new access to both directions of I-5 and the new SR 509 Expressway, according to WSDOT. Combined with new and reconstructed ramps at the existing interchange, drivers will have a smoother trip through the area and new options for getting to where they want to go.

The first thing drivers may notice this fall is a slight shift of southbound I-5, which will move towards the median so that crews can widen the I-5 bridge over Kent-Des Moines Road. Crews will also be shifting lanes on Kent-Des Moines Road under I-5.

If you walk, roll, or use transit in this area you can expect the access you have today until 2024, when one of the two eastbound bus bays will temporarily close. The new eastbound SR 516 bus stop will open later in 2024.

The West Hill area of Kent east of I-5 also is changing with Sound Transit’s extension of light rail from SeaTac to Federal Way. Part of the line will run just west of the I-5 southbound lanes. Light rail is scheduled to open in 2024.

In early 2022, work also starts on I-5 at the South 216th Street bridge on the Des Moines/SeaTac border. The 216th Street bridge will be widened and replaced to make room for ramps to the future SR 509 Expressway to pass underneath.

The SR 509 Completion Project in King County and the SR 167 Completion Project in Pierce County are managed under the Puget Sound Gateway Program and will cost about $2 billion. Together, these projects will improve the movement of freight by connecting the state’s largest ports to key distribution centers in King and Pierce counties. Completing these unfinished highways will move freight more efficiently and ease traffic congestion throughout the Puget Sound region.

The project is part of the 2015 Connecting Washington funding package approved by the Legislature, a $16 billion investment that enhances the statewide transportation system and maintains critical infrastructure. Connecting Washington is a 16-year program, funded primarily by an 11.9-cent gas tax increase that was fully phased-in on July 1, 2016.

About $1.6 billion of the Gateway Program will be covered by the gas taxes. Another $130 million is from local contributions, including about $60 million from the Ports of Seattle and Tacoma. The city of Kent will kick in $2 million.

Users of the new SR 509 Expressway will have to pay a toll, which is expected to raise another $180 million. Federal and state grants will cover the rest of the costs. The split between the SR 167 and SR 509 projects is about $1 billion each, according to WSDOT.

The SR 509 Completion Project is an eight-year project to build the remaining 3 miles of SR 509 and connect it from its existing end point at South 188th Street in SeaTac to I-5.

Current construction ends in 2025 and will be followed by a final construction project which will build the remaining miles of new SR 509 Expressway to South 188th Street. The entire SR 509 Completion Project is expected to wrap up in 2028.

Kent extended Veterans Drive to Military Road in 2006 to help prepare for the SR 509 extension.