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Speed Limit Assessment Projects

Want to request a speed limit or speed zone change?

Call the 24/7 Road Helpline at 206-477-8100 or email maint.roads@kingcounty.gov

2024 Speed Assessment Projects 

Status update

Winter 2024 

After requests for additional safety measures from the Vashon Island community, Road Services is proposing two areas of Vashon Highway for speed limit reductions in 2024. Public comment will be accepted within the comment period, February 26, 2024, to March 11, 2024.  

  • On Vashon Highway SW between SW 182nd St and SW Cemetery Road (reduction from 40 mph to 35 mph) 
  • On Vashon Highway SW between SW 127th St and SW 153rd St (reduction from 50 mph to 45 mph) 

Members of the Vashon Island community will have 14-days to comment, from February 26, 2024, to March 11, 2024 and share their feedback about this proposal with decision makers. Community members can share their feedback in any of the following three ways: 

  • Follow this link or use the QR code to fill out the response form (preferred method) 
  • Email abresslour@kingcounty.gov 
  • Write to: 
    • Amy Bresslour, Department of Local Services
      Road Services Division 
      KSC-LS-0313 
      201 South Jackson Street 
      Seattle, WA 98104 

Overview

The proposal to reduce the speed limit at each location will match the existing speed limits posted nearby. This change will provide consistency for drivers along this corridor. Traffic data shows that most drivers are already driving the proposed speed limit. The five-mile-per-hour speed reduction allows drivers more time to react to slower traffic and people crossing the road to visit local businesses, making it safer for drivers, cyclists, and pedestrians to share the road.  

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Safety benefits of speed limit reduction 

Reducing the posted speed limit has many safety benefits. Here are some key advantages: 

  • Reduced traffic collisions and severity: Slower speeds provide drivers with more time to react to potential hazards, reducing the likelihood of collisions. 
  • Improved pedestrian safety: Gives drivers more time to notice and react to pedestrians at crosswalks or along the road. Reduced speeds can also decrease the severity of injuries in case of accidents involving pedestrians. 
  • Shorter stopping distances: Slower speeds mean shorter stopping distances. This can be critical in situations where a driver needs to stop suddenly, such as when a vehicle ahead brakes unexpectedly or when approaching an intersection. 
  • Less severe crashes: Lower speeds often result in less severe crashes. This can lead to fewer fatalities and reduced injury severity among occupants of vehicles involved in accidents. 
  • Encourages walking, biking (active transportation): Lower speed limits can make roads more comfortable for pedestrians and cyclists. This can have positive effects on public health and reduce traffic congestion. 

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

2022 Speed Assessment Projects

Vashon Island 

  • Location 1: Vashon Highway SW between Burma Road SW and SW 127th
    • Proposed: reduce speed limit from 50 mph to 35 mph at this location
    • Result and action: Following public comment, the speed limit was reduced to 35 mph. The new speed limit signs were installed in early 2023.
  • Location 2: 91st Avenue SW between SW 167the Street and SW Dilworth Road
    • Proposed: reduce speed limit from 35 mph to 25 mph at this location
    • Result and action: following public comment, the speed limit was reduced to 25 mph. The new speed limit signs were installed in early 2023.
  • Location 3: SW Bank St from 96th Place SW to 95th Lane SW
    • Proposed: reduce speed limit from 35 mph to 25 mph
    • Result and action: following public comment, the speed limit was reduced to 25 mph. The new speed limit signs were installed in early 2023.

White Center

  • Location 1: Myers Way S/1st Ave S between S 99th St to S 116th St 
    • Proposed: reduce speed limit from 40 mph to 35 mph 
    • Result and action: following public comment, the speed limit was reduced to 35 mph. The new speed limit signs were installed on Myers Way S in October 2022. 

2021 Speed Assessment Projects

In 2021, Road Services proposed speed limits in two locations on Vashon Island: 

  • Location 1: Vashon Highway SW, just south of SW Burton Drive to midway along the waterfront northeast of 115th Avenue SW.
    • Proposed: Reduce speed limit from 45 mph to 25 mph.
      King County proposed to lower the speed limit from 45 mph to 25 mph at this location.
    • Result and action: Speed limit was reduced to 35 mph.
      Based on a second review of the area and public comment, King County will NOT lower the speed limit to 25 mph.
  • Location 2: Vashon Highway SW between 115th Avenue SW and Inspiration Point
    • Proposed: Reduce speed limit from 45 mph to 35 mph.
      King County proposed to lower the speed limit from 45 mph to 35 mph in this location. This area has limited sight distance and sub-standard shoulders.
    • Result and action: Speed limit has been reduced to 35 mph.
      The lower speed limit will be safer for pedestrians and bicyclists. The new speed limit signs were installed on Vashon Highway SW in late June 2021.

What is King County’s procedure for evaluating speed limits?

The King County speed limit evaluation procedure was developed using criteria based on the Washington State Model Traffic Ordinance (46.04; WAC 303-308), the King County Code and the Manual on Uniform Traffic Control Devices (MUTCD). The MUTCD is a Federal Highway Administration document, which has been adopted by most public agencies and provides guidelines for traffic control devices and pavement markings.

In 2018, the King County Council adopted an update which, in Section 46.04.040 (RCW 46.61.415-1 amended) empowers the Director of the Department of Local Services to “revise speed limits on all streets and roads within this county as authorized by state law; provided, that such speed limit revisions shall not exceed ten miles per hour; provided further, that any determination of the property numerical value for a speed zone will be based upon the following engineering and traffic investigation factors:

  1. Road surface characteristics, shoulder conditions, grade, alignment and sight distance;
  2. The eighty five percentile speed and pace speed;
  3. Roadside development and culture, and roadside friction;
  4. Safe speed for curves or hazardous locations within the zone;
  5. Parking practices and pedestrian activity;
  6. Reported accident experience for a recent twelve month period.

Speed limits on segments less than 1.0 mile in length may be changed administratively if the posted speed limit of the road segment varies from posted speed limits at each end of the road segment. These situations commonly occur where a city has annexed a portion of the roadway and changed the speed limit within city limits, leaving a short segment in unincorporated King County with a higher speed limit. In such cases, the County may administratively make a speed limit change of no more than 5 mph. In these cases, no detailed review is conducted.

Once a preliminary review of the road segment is completed, public comment is solicited for a period of two to three weeks, except when an administrative change is implemented for a short segment as discussed in the paragraph above. Public comments are reviewed by the County Traffic Engineer and County Road Engineer prior to recommending the change to the Director of the Department of Local Services for approval and transmittal to the King County Council to enact into law.

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