King County Traffic Safety Action Plan

Get involved

We want to better understand how people feel about traffic safety throughout unincorporated King County. We asked the public about what would make them feel safer walking, rolling, biking, and driving on unincorporated King County roads. Our first survey ran from August 22, 2025, to September 30, 2025. To receive regular updates on this project, please send your contact information to lideleon@kingcounty.gov. You can subscribe to receive regular project updates here. All future opportunities to share your thoughts about traffic safety will be shared to this webpage and to our subscriber list. The final report will be available February 2026 and its findings will guide planning for future improvements and allow King County to apply for funding for improvements.

The safe systems approach

As we expand on our efforts to improve traffic safety, we’ll examine public input and crash data to better understand causes of crashes in unincorporated King County. This Safety Action Plan will use a holistic, system-focused approach called Safe Systems to analyze crash data and identify potential improvements and solutions.

A graphic representation of the Safe System Approach, including: Safer road users, land use, vehicles, speeds, roads, and post-crash care. 

The Safe Systems Approach:

• Acknowledges death and serious injury as unacceptable
• Accounts for human vulnerability and mistakes
• Recognizes that responsibility is shared and redundancy is crucial to strengthen transportation systems.
• Aligns with State and Federal approaches to address traffic deaths and serious injuries.

This approach centers our work around the understanding that safety is proactive; serious injuries and fatalities are preventable; and that road safety depends on collaboration between road managers, public health organizations, law enforcement agencies, emergency responders, road users, and others. When everyone works together to implement the Safe System approach, the result is “the Swiss Cheese Model”—more layers of safety to reduce the risk of serious collisions. 

A graphic representation of the Swiss Cheese Model, showcasing how more layers of safety on our roads lead to fewer chances of road incidents. 

Understanding the problem: Fatal and serious crashes in unincorporated King County

As we strive towards zero traffic deaths and serious injuries, it’s important to understand how and why crashes happen in unincorporated King County. The vast majority of crashes on county roads do not result in a serious injury or fatality. Between 2014 and 2023, there were 17,324 crashes on county roads—of these, 545 crashes resulted in a death or serious injury on county roads. Annual serious crashes reached a low of 38 in 2018, while 2023 saw 67—the highest number in a decade.

A graphic illustrating number of crashes in Unincorporated King County, from 2014 to 2023. 

A graphic illustrating fatal and serious injury crashes in Unincorporated King County between 2014 to 2023.

Read on for more details on crashes in King County.

A graphic illustrating top contributing factors for fatal and serious injury crashes in Unincorporated King County from 2014 to 2023. 

A graphic illustrating top crash types in Unincorporated King County from 2014 to 2023. 

Safer speeds

Speeding is a top contributing factor in fatal and serious injury crashes on unincorporated King County roads. Between 2014 and 2023, speeding was involved in 30% of fatal and serious injury crashes on the County’s roads. In rural areas, that number rises to 33%. Additionally, more speeding-related serious crashes are happening in unincorporated King County compared to the state and the county as a whole, particularly in rural parts of the county. At lower speeds, drivers have a lower reaction time and stopping distance. When a pedestrian is struck by a vehicle, their risk of death increases dramatically as speeds rise.

A graphic illustrating vehicle stopping distance at different speeds, at 20, 30, and 40 miles per hour. 

A graphic illustrating pedestrian survival rates in relation to speed, from 20, 30, 40 and 50 miles per hour. 

Safer people

A Safe Systems approach plans for human mistakes. A part of any Safety Action Plan is advocating for behavior change and safer policies that promote and enable road users to make better choices. Distracted driving and driving while impaired (by alcohol and/or drugs) are common behaviors impacting safety in King County. Drivers were distracted or impaired in 37% of fatal or serious injury crashes on unincorporated King County roads from 2014 to 2023. The Traffic Safety Action Plan will examine potential policies and programs that encourage behavior change and education on our roads.

Safer streets

Roadway design affects how people behave on our roads. While big changes to roads are costly, there are often lower cost improvements that can reduce the effects of human error. For example, almost half of fatal and serious crashes on unincorporated King County roads involve a vehicle leaving the travel lane; up to nearly 60% in rural areas. These crashes often involve both speeding and other driver errors. The plan will identify where simple changes to signs, roadway markings, or the pavement surface can signal drivers to modify their behavior.

Safer land use

When our communities are planned effectively and efficiently, people can access what they need more easily. King County land use rules encourage new housing and jobs in the urban areas and limit growth in the rural areas. This means less trips in cars and more trips walking, rolling, or biking, reducing the risk of crashes.

Safer vehicles and post-crash care

Continued safety in vehicle systems, like airbag improvements, seatbelts, and other safety features, improves survivability in crashes. Post-crash care also plays a critical role in survivability. King County will continue to collaborate with public health and emergency response services to facilitate fast, effective post-crash response.