Key Takeaways:
- The deadliest 10-mile road stretch in Washington is located on I-5 in Pierce County between South 38th Street and State Road 18, recording 22 fatal crashes and 25 fatalities over a five year period.
- Among the ten highlighted deadliest road stretches in Washington, five are located on I-5.
- King County was most represented among the deadliest road stretches in Washington, with four segments making the ranking, and two landing within the top three.
- The deadliest 10-mile road stretch in King County is on I-5 from South Dearborn Street and Northeast 145th Street, with 20 fatal crashes and 20 fatalities.
A 61-year-old woman from Federal Way was killed in a hit-and-run crash on Interstate 5 near Highway 516.
A truck driver was killed after a violent crash caused the fully loaded semi to fall from an overpass on Interstate 405, closing the road to drivers in both directions
Three people were killed in a collision involving a wrong-way vehicle on Interstate 5 near the Scatter Creek Rest Area in Rochester.
A woman was killed after striking a cable barrier along Interstate 205 near West Linn.
These stories and many others like them underscore the risk that motorists take while driving on Washington highways and interstates, where speed and congestion most often play a factor. Over the past five years, traffic fatalities in Washington have increased every year from 2019 through 2023, reaching a 33-year high of 809 in 2023, before showing signs of decline in early 2024.
With so many people sharing the roads and fatal crashes remaining a serious concern, we wanted to find out: where are the deadliest road stretches in Washington?
To do so, Seattle Injury Law analyzed five years of fatal crash data from the National Highway Traffic Safety Administration (NHTSA) to identify areas where motorists are killed within close proximity of one another.
We identified ten such high collision highway stretches, where at least nine fatal motor vehicle crashes occurred within a single 10-mile segment.
Interactive Map of Washington’s Deadliest Road Stretches
To take a closer look at these road segments and their locations across the state, use the interactive map below. You can zoom into specific areas or select from key regions in Washington found in the menu.
I-5 Dominates Washington’s Deadliest Road Stretches
The table below highlights the deadliest 10-mile stretches of roadway in Washington. Each listing includes the highway name, approximate boundaries of the segment, and the city and county it runs through, along with the number of fatal crashes and fatalities recorded over the past five years. In cases where multiple stretches had the same number of fatal crashes, fatality count was used as a tiebreaker. If both the crash count and death count were equal, the stretches share the same rank.
The Deadliest Road Stretches in King County
King County was most represented among the deadliest road stretches in Washington, with four segments making the ranking, and two landing within the top three. The deadliest stretch in the county, and second overall in the state, is a segment of I-5 running through Seattle, from South Dearborn Street to NE 145th Street. It recorded 20 fatal crashes and 20 deaths over five years. This 10-mile section is often congested, as it serves some of Seattle’s busiest neighborhoods and landmarks, including Downtown Seattle, the University District, Seattle Convention Center, and more.
Another stretch of I-5 in SeaTac, from South 288th Street to Interurban Avenue South, ranks third statewide, with 18 fatal crashes and 21 deaths, which is one of the highest death counts on the list. This route is commonly used to get to Seattle-Tacoma International Airport by travelers coming from the south, including cities like Federal Way, Tacoma, and Kent.
Two more road stretches from the ranking are found in King County:
- In Renton, a segment of I-405 from I-5 to Coal Creek Parkway Southeast ranks eighth overall, with 10 fatal crashes and 10 deaths.
- Lastly, a stretch of I-90 between State Road 18 and Renton Issaquah Road Southeast ranks ninth, with 9 crashes and 10 deaths.
Deadly Road Stretches in Pierce County
Pierce County is home to the deadliest 10-mile stretch in all of Washington. This top-ranked segment lies along I-5 in Tacoma, from South 38th Street to SR 18, passing through the Puyallup Reservation. The stretch recorded 22 fatal crashes and 25 deaths. Another segment in Tacoma, running between 41st Division Drive and South 56th Street, is the second most dangerous in the county and ranks seventh statewide, with 10 fatal crashes and 11 deaths.
The WSDOT started an I-5 improvement project in 2015, with completion plans set for the end of 2025 to alleviate congestion and improve mobility around some of the deadliest stretches mentioned in Pierce County. These planned improvements include widening seven miles of I-5 from DuPont to Lakewood.
Deadly Road Stretches in Thurston and Clark County
While most of the state’s deadliest road stretches are concentrated in King and Pierce counties near the Seattle-Tacoma metro area, a few dangerous segments are located further south. Thurston County’s most fatal stretch runs along I-5 from 54th Avenue SW to Trosper Road SW, passing through Tumwater and Olympia. It ranks fourth in the state, with 11 crashes and 12 deaths.
In Clark County, the deadliest stretch also ranks fourth statewide. Located on I-205 in Vancouver, it spans from the Southeast Lewis and Clark Highway to NE 134th Street and recorded the same totals: 11 fatal crashes and 12 deaths. This stretch sits just north of the state’s border with Oregon, providing direct access to Portland and just a short drive from the Portland International Airport. This may explain the stretch’s risk, as it likely sees heavy congestion from commuters and visitors alike.
Deadly Road Stretches Snohomish and Whatcom County
North of the Seattle-Tacoma metro area, we see deadly stretches in both Snohomish and Whatcom counties. In Snohomish County, a segment along I-5 from Lowell Road to 88th Street NE, cutting through Everett and Marysville tied for fourth overall in the state, with 11 fatal crashes and 12 deaths.
Further north in Whatcom County near the Canadian border, a deadly stretch of I-5 from Lakeway Drive to Main Street spans parts of Bellingham and Ferndale. This segment ties for ninth place overall, recording 9 fatal crashes and 10 fatalities. Bellingham is one of Washington’s major ports, which may contribute to increased commercial traffic in the area.
Methodology
This analysis examined major highways and interstates throughout Washington by scanning overlapping 10-mile segments to identify those with the highest number of fatal crashes during the five-year period from 2019 to 2023. After pinpointing the deadliest segment, the process was repeated to find subsequent stretches with high concentrations of fatal crashes. Crash data was sourced from the Fatality Analysis Reporting System (FARS), a national database managed by the National Highway Traffic Safety Administration (NHTSA).
Please note that the start and end points provided in the table are estimates based on the closest intersecting road and may not represent the exact limits of each segment. For precise boundaries, please consult the interactive map included with this study.
Fair Use Statement
Feel free to share this analysis. If you republish or report on these findings, please include a link back to the original study so others can access the full data and methodology.
