In their own words, the Washington State Department of Transportation (WSDOT) said, “It’s about time for people who use the State Route 99 (SR 99) tunnel under downtown Seattle to get a grip.”

Grip as in better traction through the downtown tunnel.

Since opening in February 2019, the surface of the two-mile tunnel has worn down due to the 47,000 daily commuters, and WSDOT plans to add texture to the pavement . The $1.5 million project will restore the tire grip to its original form, as it was when the road opened more than six years ago.

A technique called shot-blasting will add traction through high-velocity particle grains. Trucks will tow machines that blast the grains and vacuum any dust created during the process, ensuring that the tunnels’ air filtration systems and storm drains

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