Map provided by Google: After careful consideration, the Roads Division has selected a roundabout to help to alleviate congestion at the SE May Valley Road and Issaquah-Hobart Road SE interchange. Larger view (3MB)
King County is planning to build a multi-lane roundabout at the intersection of Issaquah-Hobart Road SE and SE May Valley Road, located south of the City of Issaquah. The roundabout would reduce rear-end collisions and improve traffic flow through the intersection, especially during busy commute times.
This intersection improvement project is 30 percent designed and final design is expected to be complete by the end of 2024. The County is seeking construction funding and will schedule construction when funding is made available through county, state or Federal funding sources.
The roundabout will reduce rear-end collisions and traffic congestion at the intersection of SE May Valley Road and Issaquah Hobart Road SE. Issaquah Hobart Road SE is part of a regional traffic corridor that includes, from west to east: State Route 900 (Renton-Issaquah Road SE), SE May Valley Road, and Issaquah-Hobart Road SE; and from South to north: State Route 18 to Interstate 90 to the north.
Issaquah-Hobart Road SE and SE May Valley Road form a crucial traffic corridor linking local communities, but it has become increasingly congested. With a rising number of vehicles and trucks, traffic issues have grown, resulting in longer backups and more collisions.
To address these challenges, King County and the City of Issaquah collaborated on the Issaquah-Hobart Road/Front Street Corridor Study in 2018. The study aimed to tackle current and future traffic demands while enhancing safety along this vital corridor. Two recommendations were presented to alleviate congestion and enhance safety at the May Valley and Issaquah-Hobart Road intersection:
- a revised traffic signal with additional lanes
- a multiple-lane roundabout
In 2019-2020, the King County Budget allocated funds for Road Services to evaluate these recommendations, choose one option, and finalize the project's design. Following a thorough assessment in 2023, a report was published. The conclusion was that a multiple-lane roundabout would be more effective in reducing collisions and maintaining a smooth traffic flow compared to the alternative of a traffic signal.
The PDF documents below provide more information about the corridor and the methods traffic engineers used to evaluate whether a traffic signal or a roundabout would be best to help improve traffic flow and safety at the Issaquah-Hobart Road SE/SE May Valley Road intersection.
Before and after graphics
The existing intersection is signalized with 2 lanes for each approach. It operates over capacity in the morning and afternoon peak hours causing cars to back up close to the City limits at times during the evening commute.
An artist rendering of the new multi-lane roundabout on Issaquah-Hobart Road SE at SE May Valley Rd. The roundabout is designed to keep traffic moving for cars, freight, bikes, and pedestrians. The proposed roundabout also would include wider shoulders, sidewalks, pedestrian traffic islands, accessible curb ramps, and crosswalks.