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Issaquah-Hobart Road SE and SE May Valley Road Intersection Improvement Project

Satellite photo of Issaquah-Hobart Road SE and SE May Valley Road intersection

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. 

Graphic of project location at Issaquah-Hobart Road SE and SE May Valley Road intersection

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.   

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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. 


Learn more

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

Graphic of existing conditions at Issaquah-Hobart Road SE and SE May Valley Road intersection

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.    

Graphic of future conditions at Issaquah-Hobart Road SE and SE May Valley Road intersection

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.

Study intersection graphic.

The study intersection is south of Issaquah and this project is focused on the intersection of SE May Valley Road and Issaquah-Hobart Road SE interchange. Larger view 700KB

A roundabout will help keep traffic moving

There are several factors that contribute to heavy congestion in the Issaquah-Hobart corridor. The main reasons include: 

  • Heavy truck traffic
    Large freight trucks are not allowed to travel on local City of Issaquah roads, such as Front Street S., unless they are making deliveries. This means when large trucks are passing through the area, they usually drive around the City of Issaquah on State Route 900 via the Issaquah-Hobart Road SE/SE May Valley Road intersection. 
  • School bus stops along both sides of Issaquah-Hobart Road SE
    When the bus stops to pick up or drop off passengers, both directions of traffic are required to stop which ultimately causes traffic delays in the corridor. 
  • More density and growth in the area
    Nearby communities of Issaquah, Maple Valley, Black Diamond, East Renton Highlands, and other neighborhoods have been growing steadily. Because of this, there are more vehicles on the road.    

Community involvement 

In 2018, the City of Issaquah and King County Roads commissioned a study of the Issaquah-Hobart Road/Front Street Corridor after steady growth and increased traffic in the area. During the study, community members had the opportunity for input and shared their experiences with traffic in the corridor. We continue to hear about traffic congestion in this area. 

This project construction is currently unfunded. Once funding becomes available, King County will connect with residents, community members, emergency responders, schools, and other community partners to share information about all aspects of the project.

The project team would be happy to meet with individuals or community groups at any time to provide more information about the project and the status. 



  • 2018: Issaquah-Hobart Road/Front Street Corridor Study complete
  • 2019-2020: Funding allocated to evaluate ways to improve Issaquah-Hobart Road SE and SE May Valley Road intersection (identified in the 2018 study)
  • 2023: Final Concept Development Report and Preliminary Design for the Issaquah-Hobart Road SE and SE May Valley Road Intersection Improvements Project
  • 2024: Complete 100 percent design of new roundabout
  • TBD: Anticipated construction


Study intersection graphic.

Larger view (216KB)

Frequently asked questions

This project is 30 percent designed and will be ready for construction in 2025, however there is no funding available to build it yet. King County is actively seeking state and Federal funding sources and grants to fund the project. Construction will begin when funding is secured. 

Providing the most efficient, safe, and reliable traffic flow possible in this heavily traveled corridor is a high priority for the county. Funds were allocated to examine the design of one of two possible options that would do the most to improve safety and ease traffic in the entire corridor.  The study identifies project risks that could cause project delays.  Completing this analysis early helps produce a more complete construction cost estimate and timeline.  The options studied were a roundabout or a traffic signal. The roundabout was selected and is 30 percent designed and will be ready to go to construction in 2025 and/or once the project is funded. To learn more about the selection and design process, view this report (12MB)

The total project budget is $7,478,569. This project is not currently funded.

There are many projects along the Issaquah-Hobart Road SE/Front Street Corridor that were identified in the 2018 Study and are listed in the King County Transportation Needs Report. King County has decided to start improvements with the project that will make the biggest difference to reduce congestion along the entire corridor (12MB)

A roundabout at the intersection of Issaquah-Hobart Road SE and SE May Valley Road will address high traffic backups and frequent collisions at this specific location. A traffic signal would cost more in terms of safety, operational delays, and installation costs. 

County traffic engineers looked at two separate alternatives. The current traffic signal is operating over capacity.  The signal option includes adding addition lanes at the intersection to allow more traffic through during each green light.  A traffic signal requires drivers to come to a complete stop at the intersection. A full stop can cause high-speed rear-end collisions on Issaquah-Hobart Road SE. A roundabout that slows but does not stop traffic is the safest and most cost-effective choice for this growing region of King County.  The signal alternative also requires widening of Issaquah Hobart Rd north of the intersection.  This directly impacts a culvert and stream crossing under the arterial adding cost and permit requirements to the project.