I-90 - SR 18 Interchange Improvements - SE 104th Street Improvements

Proposed improvements at the intersection of State Route 18 and Southeast 104th Street

As part of the I-90/SR 18 interchange improvement project, the Washington State Department of Transportation will also make changes to the intersection at Southeast 104th Street. The proposed configuration will improve safety for drivers entering and exiting the highway at Southeast 104th Street as well as benefit traffic flow through the I-90/SR 18 interchange. The image below shows the proposed two-way stop, a protected left-hand turn lane barrier, a U-turn option and a new flashing traffic signal.

Southeast 104th street design recommendations

After comparing key criteria and design options, WSDOT recommends a two-way stop at this intersection. This project will be delivered through a method called design-build. This type of contract authorizes the awarded firm to decide if WSDOT’s proposed traffic revision is the best solution or to design a different, more cost-effective option. This means the new intersection could look different from the one WSDOT has recommended.

A map of the upcoming improvements to SE 104th St near the I-90/SR 18 interchange

Proposed SR 18 and Southeast 104th Street intersection improvements

  • Widen SR 18
  • A barrier protected left-turn lane on westbound SR 18 to Southeast 104th Street
  • Barriers on SR 18 and Southeast 104th Street
  • A signalized U-turn in the SR 18 median just before the I-90/SR 18 interchange
  • Traffic safety beacon prior the SR 18/Southeast 104th Street intersection to alert approaching traffic to cars turning onto SR 18