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Redmond Ridge Drive NE and NE Alder Crest Drive Roundabout Project

The new roundabout at Redmond Ridge Drive NE and NE Alder Crest Drive opened to traffic on Monday, November 13, 2023.

Status update

March 12, 2024

 

The roundabout will close daily on Thursday, March 14th and Friday, March 15th from 7:00 a.m. to 5:00 p.m. for repairs. Local traffic to use NE Cedar Park Crescent as a detour route. Emergency vehicles will have access through the work zone. Visit kingcounty.gov/MyCommute for the latest information.

Final paving is scheduled for Monday, March 18th and Tuesday, March 19th from 7:00 a.m. to 6:00 p.m. each day. During these work hours, the road will be closed. Local traffic to use NE Cedar Park Crescent as a detour route. Emergency vehicles will have access through the work zone, however, there may be delays. Visit MyCommute for the latest information. 

We thank the Redmond Ridge community for your continued patience.

For the most up-to-date status, visit kingcounty.gov/MyCommute. 

24/7 Road Helpline

24/7 Road Helpline

Call us for help at 206-477-8100 or 1-800-527-6237 with road maintenance and traffic safety issues in unincorporated King County — 24 hours a day

Project overview

King County is building a single-lane roundabout at the intersection of Redmond Ridge Drive NE and NE Alder Crest Drive. The new roundabout is designed to make it easier for pedestrians, wheelchair users, bicycles, and people with strollers to use the intersection.

Construction work started in September 2023 and will last up to four months. Traffic lane restrictions and occasional full intersection closures are expected. Crews will post a signed detour when the intersection is closed.

Local access to businesses and athletic fields will be maintained throughout the project.

Planning ahead to keep traffic moving in the future

Continued growth of the Redmond Ridge community and nearby business park will bring a lot more vehicle traffic to this intersection in the coming years. Building a roundabout now will help manage projected traffic increase, prevent speeding, and make the intersection safer for middle school students and people walking or rolling to and from the local park and athletic fields. This project provides the county with a rare opportunity to plan now for what the future will bring. Most of the design and construction costs are paid for with state traffic and pedestrian improvement grant money.

Project location map

King County is building a new roundabout at the intersection of Redmond Ridge Drive NE and NE Alder Crest Drive. Larger version  PDF 117KB

What the new roundabout will look like

Artist rendering of the new single-lane roundabout.

An artist rendering of the new single-lane roundabout on Redmond Ridge Drive NE at the intersection of NE Alder Crest Drive. Larger view, JPG 2MB

How to use the roundabout

All vehicles may enter the intersection from all four entry and exit points of the roundabout. Drivers enter the roundabout by yielding to traffic that is already in the circle and drive in a counterclockwise direction until they reach their desired exit point.

Extra room for large trucks

The central island includes a truck apron, a raised section of red concrete that acts as an extra lane for large vehicles. The back wheels of the oversize vehicle can ride up on the truck apron so the truck can easily complete the turn.

Pedestrians and non-motorized vehicles

Signed crosswalks and separated sidewalks allow people to safely walk across all lanes. Accessible curb ramps will make it easier for bikes, strollers, and wheelchairs to use the crosswalks.



Example roundabout at Redmond Ridge Road NE and NE Cedar Park Crest Drive.

The new roundabout will function similarly to this roundabout (above) at Redmond Ridge Road NE and NE Cedar Park Crest Drive, just on half-mile to the south. This roundabout has been working well for local users since it was finished in 2012.

What to expect during construction

Construction began in September 2023 and last approximately four (4) months.

Lane restrictions

We will keep one lane open in both directions of Redmond Ridge Drive NE most of the time. 

  • Most days, crews will work from 7 a.m. to 3:30 p.m., Monday through Friday. Expect short delays up to 5 minutes to get through the intersection.  
  • Pedestrians and bicycles will maintain access throughout the entire project.
  • Local access to schools, businesses, and athletic fields will be maintained.
  • All lanes are expected to reopen at night and weekends. 

Emergency response (Fire, Ambulance, Sheriff) during construction

  • The county is coordinating closely with Redmond Fire Station 18, located on the northwest corner of the intersection to minimize impact to response times during construction.
  • During the intersection closure, emergency vehicles will maintain access.
  • Emergency responders will be notified well in advance of any full intersection closures or other construction-related restrictions.

Construction hours and noise

  • Crews will work Monday through Friday, 7 a.m. to 3:30 p.m..
  • People living or working nearby may hear noise from jackhammers, trucks, generators, and other construction equipment.

Detour map

Detour route map.

The detour shown above will be in place on days when the intersection is closed to traffic. Drivers from Novelty Hill Drive NE will use NE Cedar Park Cres and connect to Redmond Ridge Drive NE to get around the closed intersection. Larger version JPG 449KB

Project timeline

  • September 2023 – Construction begins
  • October 23, 2023 – November 13, 2023  – 21-day full closure  
  • December 2023 – Construction complete

Project budget

The total cost of this project is $1.54 million. It is mostly funded through state traffic and pedestrian improvement grants. A small amount of county resources have also been allocated to this project.

Frequently asked questions

This project provides the county with a rare opportunity to plan now for what the future will bring. Building a roundabout now will help manage projected traffic increase, prevent speeding, and make the intersection safer for middle school students and people walking or rolling to and from the local park and athletic fields.

County traffic engineers looked at several alternative traffic-calming options. Both a traffic light and four-way-stop would require drivers to come to a complete stop at the intersection. A full stop could increase high-speed rear-end collisions on NE Redmond Ridge Drive. A roundabout that slows but does not stop traffic is the safest and most cost-effective choice for this growing region of King County.

We are working with the Redmond Fire Department and other emergency responders to ensure timely access to and from the fire station throughout construction.

Most buses and trucks can get through a single lane roundabout. The central island includes a truck apron, a raised section of red concrete that acts as an extra lane for large vehicles. The back wheels of the oversize vehicle can ride up on the truck apron so the truck can easily complete the turn.

The intersection was completely closed for several weeks during the four-month construction project. Drivers used a posted detour. We maintained through traffic when the intersection was open. During the full intersection closure, emergency vehicles continued to have access.  

We will do our best to keep community members informed about the project. Project updates and construction closure information will be shared in the following ways:
  • Time-stamped updates to this website and our MyCommute website
  • Flyers to nearby businesses, recreational facilities, and neighbors
  • Project notification signs at the construction zone
  • Signs alerting drivers to upcoming intersection closures and signed detour route
  • Road Alert email notifications about this project and others throughout unincorporated King County. Sign up for Road Alert emails here.
  • Posts on Twitter, NextDoor, Facebook, and Instagram
The center island is designed for low maintenance and drought tolerance. The county plans to plant one tree and several lavender bushes inside the center island.

The three large trees located on the southwest corner of NE Alder Crest Drive and Redmond Ridge Drive NE and several smaller trees in the area were removed to make way for the new roundabout lanes. The project will re-plant at least nine (9) new trees, two on each corner and one in the center island, as mitigation.

Buses are not allowed through the active work zone during the 14-day full closure for several reasons:

a. Safety. If a bus carrying students gets stuck 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.

b. Heavy vehicles could damage sub-surface. The heavy weight of vehicles damages the roadwork and could require repairs which would extend the full closure and increase the cost of the project.

c. 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 vehicles will be allowed through the work zone because the fire station across the street relies on the intersection to get fire engines in and out of the station. Fire engines and other response vehicles are also equipped to drive over uneven surfaces. If they get stuck, their trained drivers and staff are much more equipped to handle being inside of an active construction area than the general public. 

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.
Postponing construction until the summer of 2024 was 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. 

Photos

 

November 9, 2023: crews prepare the first layer of asphalt for paving the new roundabout at the intersection of Redmond Ridge Drive NE and NE Alder Crest Drive.  

 

Crews plan the next steps of the Redmond Ridge roundabout at NE Alder Crest Dr.

Oct. 31, 2023 – Crews plan the next steps of the Redmond Ridge roundabout at NE Alder Crest Dr. 

 

New roundabout under construction.

Oct. 31, 2023 –Vehicles will be able to enter the intersection when it’s complete from all four entry and exit points of the roundabout. Drivers enter the roundabout by yielding to traffic that is already in the circle and drive in a counterclockwise direction until they reach their desired exit point.

 

A crew member takes more measurements to ensure that after the grinding, the remaining hot mix asphalt (HMA) thickness is the King County standard.

Oct. 31, 2023 – A crew member takes more measurements to ensure that after the grinding, the remaining hot mix asphalt (HMA) thickness is the King County standard. 

 

October 5, 2023: Crews scrape away the road to make space for the new roundabout at the intersection of Redmond Ridge Drive NE and NE Alder Crest Drive 

 

West on NE Alder Crest Drive approaching NE Redmond Ridge Drive

A view of the intersection before the start of construction. The photo above faces west on NE Alder Crest Drive approaching NE Redmond Ridge Drive. The Redmond Fire Station is across the street on the right-hand side.

 

Redmond Ridge Drive facing north.

Redmond Ridge Drive facing north. Photo taken before the start of construction.

 

Aerial view of the new roundabout location.

King County will build a roundabout at this intersection to manage the increase in traffic near the City of Redmond.

 

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