New chain-up system helps improve safety and efficiency for westbound I-90 drivers

WSDOT-LogoWith snow in the forecast, truckers may need to chain up on Interstate 90 over Snoqualmie Pass this weekend, but putting chains on a big rig in the snow can be challenging. The designated westbound area, 3 miles east of the pass, often exceeds capacity, pushing large trucks into live traffic.

The Washington State Department of Transportation is implementing a pilot project to try and solve westbound chain-up woes. The new system will be used throughout the winter when traction tires are required on trucks over 10,000 pounds.

Recent improvements to I-90 nearly doubled the length and width of the westbound chain-up area. Overhead message signs help guide trucks in the chain-up area, streamlining the process and helping improve safety for all drivers on I-90.

NOTE:  This new system is only being implemented in the westbound chain-up area about 3 miles east of the Snoqualmie Pass Summit.

Here’s how the system works:

  • When traction tires are required, trucks traveling westbound and are over 10,000 pounds must chain up.
  • Overhead signs will direct trucks to the westbound chain-up area and notify trucks where a chain-up space is available.
  • Double parking is not allowed with the new system; trucks will chain up in a single-file line.


Passenger vehicles traveling westbound do not have to chain up when traction tires are required, but those that want to can follow the overhead signs, as well.


WSDOT recently widened the westbound chain-up area shoulders to allow extra space between drivers chaining up and live traffic. This will help reduce the risk of pedestrian collisions.

Truckers will be allowed to park for 30 minutes while chaining up and will not be allowed to park in the chain up area to wait out the storm.

WSDOT believes this is the first time engineers have used Intelligent Transportation Systems to actively organize the chain-up process. If successful, this pilot project may be expanded to other areas in the I-90 corridor and across the state.


Hyperlinks within the release: