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New guardrail in unincorporated King County.

Damaged guardrail.
Damaged guardrail will be repaired or replaced.

New guardrail installation and tree removal begins in winter and spring 2021

Beginning in winter and spring 2021, King County will install new guardrail to improve driver safety in northeast and southeast King County and Vashon Island. Work takes place February through December 2021.

Tree and stump removal

As part of the new installation work, trees and stumps within 3 feet of the guardrail will be removed to improve safety on the following roads listed below. This type of work requires crews to focus on a few trees at a time with the work moving quickly through your neighborhood.

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Broch Bender, Communications Manager
Desk 206-263-1189

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2021 project location maps

Map of North King County guardrail projects.
2021 North King County guardrail projects

Map of South King County guardrail projects.
2021 South King County guardrail projects
Tier 2 guardrail locations
Work begins in February 2021
# Location Work
North King County
1 NE Ames Lake Road
State Route 202 to West Snoqualmie Valley Road NE
Guardrail upgrades Completed
2 West Snoqualmie Valley Road NE
Ames Lake Carnation Road NE to King-Snohomish County line
Guardrail upgrades Completed
204th – 208th Avenue NE
State Route 202 – NE Union Hill Road
Guardrail upgrades Completed
SE Duthie Hill Road
From #28212 to about 1500’ north
Guardrail upgrades, tree removal (1) Completed
SE Cougar Mountain Drive
To Harvey Manning Trailhead
Guardrail upgrades Completed
148th Avenue NE
Between 140th Place NE & NE 146th Place
Guardrail upgrades Completed
NE Cherry Valley Road
Northeast of Duvall
Guardrail upgrades Completed
South King County
164th Avenue SE
State Route 900 – SE 128th Street
Guardrail upgrades Completed
212th Way SE
S 358th Street and Green Valley Road
Guardrail upgrades Completed
Cedar Falls Road SE
I-90 to Rattlesnake Lake
Guardrail upgrades Completed
11 SE 216th Way/Street
State Route 169 to 276th Avenue SE/Issaquah-Ravensdale Road
Guardrail upgrades Completed
12 Veazie-Cumberland Road SE
At SE 352nd Street and SE 392nd Street
Guardrail upgrades Completed
13 55th Avenue S
Approximately 966' south of S 277th Street
Guardrail upgrades Completed
14 S 321st Street
Between 51st Avenue S & S Peasley Canyon Road
Guardrail upgrades Completed
15 Cedar Grove Road SE
State Route 169 – Issaquah-Hobart Road SE
Guardrail upgrades Completed
16 SE Covington-Sawyer Road
Thomas Road SE to 215th Avenue SE
Guardrail upgrades Completed
Vashon Island
17 SW Quartermaster Drive
Between Monument Road SW & Vashon Highway SW

107th Avenue SW
Between SW 238th Street & 105th Avenue SW
Guardrail upgrades, tree removal (2) Completed
Tier 3 guardrail locations
Work begins in October 2021
# Location Work
North King County
1 NE 132nd Street
Avondale Rd NE to Bear Creek Road (bridge)
Guardrail upgrades, shoulder restoration
2 NE 133rd Street
Bear Creek Road to Trilogy Parkway NE (including bridge)
Guardrail upgrades, shoulder restoration
3 6th Avenue S
Myers Way S to S 112th Street
Guardrail upgrades, shoulder restoration
4 8th Avenue S
S 103rd Street to S 112th Street
Guardrail upgrades, shoulder restoration
5 S Langston Road
64th Avenue S to 78th Avenue S
Guardrail upgrades, tree removal (3 + 1 stump), shoulder restoration
6 SE May Valley Road
164th Avenue SE to SR-900
Guardrail upgrades, tree removal (1 + 1 stump), shoulder restoration
South King County
7 Cedar Grove Road SE
Bridge near Byers Road
Guardrail upgrades, shoulder restoration
8 164th Avenue SE
SE 224th Street to SE 240th Street
Guardrail upgrades, shoulder restoration
9 196th Avenue SE
SR-164 to SE 400th Street
Guardrail upgrades, shoulder restoration
10 SE 208th Street
140th Avenue SE to 148th Avenue SE
Guardrail upgrades, shoulder restoration
11 Tiger Mountain Road SE
Issaquah Hobart Road (N) to Issaquah Hobart Road (S)
Guardrail upgrades, shoulder restoration

Frequently asked questions

Guardrail is designed to keep vehicles upright in the event of a crash. When a vehicle rolls over or lands on the side, injuries are likely to be more severe. Barrier systems like guardrail keep the vehicle on the shoulder and upright which leads to less severe injuries.
The county is the local government for unincorporated areas of King County. Guardrail, which saves lives and reduces serious injury, is part of an on-going roadside safety program. The King County Strategic Plan commits to safe mobility and a local government that is efficient and accountable.
Placement of guardrail is based on a number of factors including topography, the length of the need, speed, alignment, and a five-year crash history focused on run-off-road collisions. Adverse road and weather conditions are also considered.

All traffic crash and collision data is reported and stored at the Washington State Transportation Data, GIS, and Modeling Office. This office is the source for the most complete and up-to-date information regarding any location in Washington State and is the source we use for crash and collision information. For information on crashes on your roadway, submit your data request to the Transportation Data, GIS, and Modeling Office.
We will spend $3.5 million to install new and modify existing guardrail to bring it up to current standards.
Please report damage to guardrail to our 24/7 Road Helpline at 206-477-8100 or toll-free at 800-527-6237, or you may email
Guardrail is installed by driving posts into the soil rather than by disturbing or removing soils. The compaction brought about by the process makes the posts more stable. In some cases where underground utilities or drainage is close to guardrail, holes are created using a large vacuum, the post is placed and the soil is compacted around it.
The County is responsible for maintenance of both the roadway and the shoulder which can include vegetation, wetland or nearby waterway. Protection can include straw mulch and logs to retain and filter water run-off.

For guardrail over rivers and streams, environmental engineers work with the Washington State Department of Fish and Wildlife to determine if there is an adverse impact. Typically, Washington State Department of Fish and Wildlife Hydraulic Project Approvals are secured for the project which include specific requirements to contain any debris.
Procurement of guardrail materials is up to the contractor(s) awarded the construction contract(s), with the exception of some end terminals which the contractor is directed to provide.
Guardrail is intended to absorb the energy of a crash by bending up to three feet. All trees within three feet of the guardrail are being removed. Roadways are safer when there are no immovable obstructions in the shoulder area or “clear zone”. Removing trees along the roadway edge could save lives by reducing the chance that a vehicle will crash into one of them if the vehicle veers off the road.
A Clear Zone is the area adjacent to a road where a driver can safely stop or regain control of a vehicle that has left the roadway, without hitting an immovable object (such as a utility pole or a tree). Some roads use paved shoulders as a clear zone, while others use the unpaved public right-of-way, up to ten feet from the edge of the road, as a clear zone. King County and WSDOT standards require all public roads to have adequate clear zones.
King County will only remove trees that are:
  • Located on a roadway scheduled to receive guardrail.
  • Within the public right-of-way (not on private property), within three feet of the edge of the travel lane.
  • Have a trunk larger than 4 inches diameter.
King County traffic safety engineers and landscape architects evaluate and determine if a tree must be removed from the side of the road. First, the traffic safety engineer and landscape architect identify trees that appear to be in the clear zone along the road. Next, each identified tree is then appraised to see if it meets the County’s requirements for removal. Requirements for removal include location, diameter, species, health and most importantly distance from the edge of the lane. If a tree meets the requirements it is tagged for removal.
Once a tree is removed, the trunk and branches are used in local wetlands and streams to slow or direct the flow of water and provide a natural habitat for animals. In some cases, the trunks are donated to local tribes and other environmental stewardship groups for reuse.
Road Services is working with the County’s Water and Land Resources Division to replace and replant trees as part of that division’s existing tree replacement program.
Dead or dying trees located along the road edge could fall onto the roadway during windy or stormy weather. These trees are generally identified and removed by the county landscape architect before they create a potential hazard for motorists.
Contact us

24/7 Road Helpline: 206-477-8100 or 1-800-527-6237

TTY Relay: 711

Twitter: @KCRoads