S 360th Street at Military Road S Roundabout Project
Project scheduled for construction in 2025
Heavy, fast-moving traffic on southbound Military Road S leaves few gaps to safely enter the two-lane road the intersection from S 360th Street.
We will improve safety and traffic flow at this intersection with a single-lane roundabout. The project is scheduled for construction in 2025.
Status update
August 4, 2023
This project was initially scheduled for construction in summer 2024, however it has been postponed to summer 2025.
Project overview
King County will build a single-lane roundabout at the intersection of Military Road S and S 360th Street, in the Lakeland South neighborhood. Roundabouts are proven to reduce collisions, calm traffic and prevent long wait times. With traffic continuing to grow in the area, especially on Military Road S, a roundabout at this intersection will keep motorized and non-motorized vehicles moving smoothly for the next 20 years.
This project also includes wider shoulders, sidewalks, accessible curb ramps and crosswalks.
Why is a roundabout needed at this intersection?
Military Road S is a heavily traveled main road with no signals or stop signs for four miles. As more people move to the region, this road and others, including S 360th Street, have seen a significant increase in traffic. More traffic at busy intersections brings longer wait times and a higher rate of crashes.
- Drivers on S 360th Street that need to cross or turn onto Military Road S must wait a long time for a gap in traffic.
- Most of the reported collisions at this intersection are a result of vehicles colliding into oncoming traffic while attempting to turn or cross Military Road S.
A roundabout at this location will calm speeding traffic in this growing neighborhood and make it easier for vehicles to turn on and off Military Road S.
Project documents
- SEPA Notice of Action Taken (NAT) PDF 349KB – Issued June 9, 2022
- SEPA Determination of Nonsignificance (DNS) PDF 250KB – Issued April 7, 2022
- SEPA Environmental Checklist (ECL) PDF 19MB – Signed March 30, 2022
Frequently asked questions
- Make no change
- Add left-turn lanes to Military Road S and S 360th Street in both directions
- Install a traffic light and make no other changes to the intersection
- Install a traffic light and add left-turn lanes just to Military Road S
- Install a traffic light and add left-turn lanes to both roads
- Build a single-lane roundabout
- Build a two-lane roundabout
Photos
S 360th Street looking west. This busy road to and from Interstate 5 passes two schools, a Buddhist temple, and several neighborhoods.
Military Road S looking south. This car is turning onto westbound S 360th Street. A stoplight here could lead to rear-end collisions on this busy arterial. Instead, a roundabout smooths and calms traffic so cars like this can safely turn and not worry about southbound traffic.
S 360th Street looking toward northbound Military Road S. This is a tricky intersection because Military Road S curves just to the south and S 360th Street comes in at an angle.
A half-mile to the south is Five Mile Park, a popular park with a playground, lake, and picnic tables. During the summer, Military Road S is extra busy with visitors who come and go to this park.