SR 169 Study

SR 169 Safety Study

Safety study purpose

State Route 169 runs between the cities of Renton and Enumclaw and is a vital north-south Puget Sound commuter and freight route. Rapid growth and development in the area have resulted in peak-hour congestion that places significant demand on the highway system.

Several cost-effective safety changes have been made to SR 169 in the past, and in 2016 the Washington State Legislature called for a safety performance study of the highway. This study reviews the section of SR 169 between Maple Valley and Renton, which is predominantly a rural, two-lane highway connecting users from Enumclaw, Black Diamond and Maple Valley to SR 18 and I-405.

Safety performance

To analyze safety performance, WSDOT uses its Highway Safety Improvement Program. The program aims to reduce the frequency and severity of crashes with a data-driven approach, allowing WSDOT to focus resources on locations with the greatest potential for safety performance improvement.

Community engagement

Community engagement is also integral to the safety study process. The SR 169 safety study engaged more than 1,200 stakeholders and community members via an in-person open house and an online survey. Public engagement efforts focused on stakeholders and businesses along the corridor as well as community members in and near Maple Valley, especially daily users of the corridor.

The end result

The Highway Safety Improvement Program and community feedback identified ten locations for analysis. These locations will be further evaluated and, where appropriate, countermeasures will be assessed based on their potential for fatal and serious injury crash reduction and cost-effectiveness Low-cost strategies have been identified that can be implemented in the near-term such as warning signs and reflective guideposts. The Cedar Grove intersection was identified for further evaluation as a potential candidate for more substantial improvement of pedestrian and transit facilities, along with overall intersection operation enhancement.

View fact sheet and map of locations and strategies (pdf 2 mb).

Throughout the corridor, a common contributing circumstance to fatal and serious injury crashes was alcohol. WSDOT will collaborate with Washington State Patrol and other agency partners to identify and implement actions that focus on eliminating these occurrences.

Community feedback largely focused on issues related to existing traffic congestion along the route. Highway congestion impacts to motorist’s travel time and perceived safety were common input from the study participants, but in large part are not directly related to more severe crashes that have occurred. Currently there is no funded SR 169 mobility project authorized by the Legislature.

WSDOT has submitted the SR 169 Safety Study report to the legislative transportation committees. Full report: SR 169 Safety Study Maple Valley to Renton (pdf 10 mb).

Funding the study

The safety study is funded through the 2016 state transportation budget. 


2016 Summer

  • Data collection and analysis

2016 August - October

  • Stakeholder communication
  • Community engagement
  • Open house and online survey

2016 October - December

  • Identify recommendations
  • Submit final report to Legislature


Travis Phelps, communications

Harmony Weinberg, communications