Redmond Ridge Roundabout Project details

Project Timeline

• Mobilization of equipment: Week of Sept. 11 (unsure of specific dates because they are finishing up work on another project)
• Construction begins: As early as Sept. 13 or during the week of Sept. 18. (We will know more on Monday, Sept. 11).
• Full intersection closure for 14 days in a row: Middle or late October through early November (dates are not yet determined. The 14 days are calendar days, crews will work on nights and weekends as needed to avoid an extension.
• Project completion: Late fall 2023 (Late November or December)

Work hours

• Crews will work from 7 a.m. to 3:30 p.m. Monday through Friday.
• Contractor cannot adjust the hours because work requires as much daylight as possible, and daylight will start to disappear sooner as the days progress toward winter.
• Contractor is unable to temporarily adjust start and end times now through the end of Daylight Saving on Nov. 5.  

Lane restrictions through the intersection – Only during work hours

• There will be at least one open lane in each direction of the intersection. Flaggers will direct traffic.
• Expect short delays up to 5 minutes to get through the intersection.  
• All lanes are expected to reopen at night and weekends when crews are not working.

Full 14-day intersection closure (all vehicles except emergency response)

The purpose of the closure is to build the roundabout lanes from the ground up. Crews will build the subgrade and pour several layers of asphalt and concrete. Exact dates are to be determined; however, the closure is expected to begin in middle or late October and last through late October or early November.

• The intersection will be closed for 14 consecutive calendar days, weather permitting.
• The posted detour is expected to add approximately five minutes to all trips.
• Crews will work on nights and weekends if needed.
• The full closure cannot be pushed out until December (winter break) because:
• Crews cannot start building the driving lanes in the roundabout until other critical sections of the roundabout infrastructure are in place.
• Mid-October is the soonest our contractor thinks the project will be ready to start building the driving lanes through the roundabout.
• Pushing the work out to wintertime or December increases the likelihood that it will be too cold and too wet to pour concrete and cure asphalt for the driving lanes.
• Buses will not be allowed through the intersection during the full closure for the following reasons:
• Safety. If a bus carrying students gets stuck in the active construction zone due to uneven surface or other dangerous work zone conditions, then it could take time for the bus to be removed from the site (which could slow or stop work and extend the full closure). More importantly, the students would need to de-board in an active construction zone, which is highly unsafe for anyone not wearing personal protective gear let alone children.
• Heavy vehicles could damage sub-surface. The bus would have to drive on subgrade, which is the foundation or base layer of the road. The foundation layer is critical for the stability, durability, and longevity of the road. The heavy weight of vehicles damages subgrade and could require repairs which would extend the full closure and increase the cost of the project.
• Frequency. Crews would need to stop work and temporarily shore up the road multiple times per day to allow buses to pass through the active workzone. The amount of time and effort it would take for crews to make it so that busses could safely cross through the intersection would extend the closure (which would impact the entire surrounding community) and add significant cost to the project.
• Emergency response vehicles will be allowed through the intersection when it is closed for the following reasons:
• Safety: The fire station located adjacent to the intersection relies on the intersection to get fire engines in and out of the station.
• Fire engines and other response vehicles are equipped to drive over uneven surfaces. If they get stuck, the trained adult drivers and staff are much more equipped to handle being inside of an active construction area.

Why the project could not be completed in summer 2023:

King County made a sincere effort to initiate work on the roundabout project in early spring 2023. Our initial plan was to schedule the full intersection closure for June or early July when school was out of session. Despite our dedicated efforts, we unexpectedly encountered challenges during both the project review and approval process and in securing a contractor for the project. Consequently, actual start of construction was postponed until late summer 2023. Additionally, it is important to note that postponing construction until the summer of 2024 is not feasible due to funding constraints. We understand the inconvenience this may cause, especially when it comes to transportation to and from Timberline Middle School and neighboring schools. Our Road Services team is actively collaborating with the project contractor to complete the project as swiftly as possible.