Deadliest highways and corridors around Seattle and Tacoma

If you drive between Seattle and Tacoma often, you probably already know which stretches make you tense up. The data backs that up. Washington recorded 731 traffic deaths in 2024, a decline from 808 in 2023, the highest death toll the state had seen in 33 years, according to preliminary numbers from the Washington Traffic Safety Commission (WTSC).¹ Pedestrians accounted for 155 of the 2024 deaths, barely down from 160 the year before.¹ The statewide trend is finally bending the right direction, but a handful of specific roads and intersections in this metro area still do an outsized share of the damage.

South Seattle, downtown, and Aurora Avenue North

Seattle's own crash data shows a clear pattern. The Seattle Department of Transportation (SDOT) reports that the highest concentration of serious injury and fatal crashes happens in South Seattle, followed by downtown and the north end of the city.² Zoom into the corridor level and three streets stand out on SDOT's High Injury Network: Rainier Avenue South, 4th Avenue South, and Aurora Avenue North.²

Aurora Avenue North, signed as State Route 99 through the city, carries an outsized share of that damage on its own. It accounts for roughly 20% of all traffic deaths citywide.³ Wide travel lanes, high posted speeds, and long gaps between marked crosswalks make it especially dangerous for anyone on foot.

People walking and biking absorb most of the harm on Seattle's worst streets generally. Between 2018 and 2022, people walking or rolling and people biking made up 38% and 13% of all fatal and serious injury collisions, even though those modes account for only 20% and 3% of citywide trips.² Speed decides who survives: SDOT's own materials note that roughly 9 in 10 pedestrians survive being hit at 20 mph, about 5 in 10 survive at 30 mph, and only 1 in 10 survive at 40 mph.² Nearly half of the city's severe crashes, 48%, happen during darkness, dawn, or dusk.²

Seattle has proof that rebuilding a street works. The first phase of safety changes on Rainier Avenue South, finished in 2015, included a road diet, signal upgrades, and a lower speed limit. Collisions there dropped 15%, injury collisions fell 30%, and crashes involving people walking, rolling, or biking fell 40%.² Even so, the city lost 224 people and saw another 1,643 seriously hurt between 2015 and 2023, including 30 deaths in 2022 alone, and citywide serious-injury and fatal totals have still trended upward since the program began, even with those localized wins.² Seattle is now using a $25.64 million federal Safe Streets and Roads for All grant, plus another $21 million in local match, to fund safety work at up to 95 priority locations concentrated in Rainier Valley, SODO, downtown, and the University District.²

King County's roads outside the city limits

Away from Seattle proper, King County's Road Services Division logged 1,646 collisions on county-maintained roads in 2024, including 11 fatal and 500 injury crashes.⁴ Impaired driving is a significant factor: 110 of those collisions, 6.7% of the total, involved a driver suspected of DUI, up from 101 (6.0%) the year before.⁴ Nearly two-thirds of all 2024 county-road collisions were a fixed-object crash, an angle collision at an intersection, or a rear-end, and fixed-object crashes alone accounted for five of the county's 15 traffic deaths that year, a third of the total.⁴

I-5 and SR-509 through Tacoma

South of Seattle, trouble concentrates around the industrial Tideflats, where Interstate 5, State Route 509, and the Port of Tacoma all meet. The intersection of SR-509 and Alexander Avenue East became the subject of a WSDOT Intersection Control Evaluation in May 2020, after the agency logged 107 crashes there between 2013 and 2018, including one serious injury and 37 possible minor injuries.⁵ The study pointed to driver inattention and red-light running as the leading factors, and concluded that a roundabout there "would be expected to noticeably reduce fatal and injury crashes compared to a signal."⁵

That redesign didn't come soon enough for six young adults, all Arizona residents between 19 and 25 years old, headed to an Amway convention in Tacoma when they were killed at that intersection on July 16, 2023. Their rented Kia Forte ran a red light and was struck by a BMW SUV that came through on a yellow light, with the BMW estimated at 50 to 66 mph on impact.⁵ Lawsuits filed against the state and the City of Tacoma cite 99 more reported crashes at the intersection between 2018 and 2022, one of them fatal.⁶

The danger on that stretch of SR-509 hasn't gone away. On December 19, 2025, Washington State Patrol Trooper Tara-Marysa Guting was struck and killed while standing outside her patrol car investigating an earlier crash on southbound SR-509 near milepost 2, close to the Port of Tacoma Road on-ramp.⁷ WSDOT has said it owns the traffic signals at the Alexander Avenue intersection, even though the city of Tacoma operates and maintains them, and that near-term safety work there could begin as early as 2024, ahead of the broader SR 167 Completion Project that will finish the highway connection between Puyallup and the Port of Tacoma as part of the state's Puget Sound Gateway Program.^{6 8}

The City of Tacoma adopted its own Vision Zero resolution in 2020, setting a goal of eliminating traffic deaths and serious injuries by 2035.⁹ Streets currently under safety review as part of that plan include Pacific Avenue, Portland Avenue, and South Tacoma Way, along with South Yakima Avenue and South Pine Street, corridors that combine heavy vehicle traffic with a lot of people walking and using transit.⁹

What this means if you're driving these roads

None of this means you should avoid I-5 or stay off Aurora Avenue. It means the data points to specific places worth extra caution: the Tideflats interchange where SR-509 meets Alexander Avenue, Aurora's long mid-block stretches after dark, and the arterials on Seattle's High Injury Network where a road diet hasn't reached yet. If you're hurt in a crash on one of these corridors, it's worth talking to an attorney who knows the local geography and the agencies involved. The legal directory is a place to start.

This is general information, not legal advice.

Sources

1. Washington Traffic Safety Commission, "Preliminary Traffic Fatality Numbers for 2024 Decrease from 33-Year High in 2023," May 28, 2025. https://wtsc.wa.gov/20555-2/

2. Seattle Department of Transportation, "Vision Zero Action Plan: 2024 Update," May 2024. https://www.seattle.gov/documents/Departments/SDOT/VisionZero/VZ_Action_Plan.pdf

3. Cascade PBS, "Is Seattle a walkable city? Pedestrian death rates show otherwise," April 2024. https://www.cascadepbs.org/news/2024/04/seattle-walkable-city-pedestrian-death-rates-show-otherwise/

4. King County Road Services Division, "2024 Collision Data Report," November 24, 2025. https://cdn.kingcounty.gov/-/media/king-county/depts/local-services/roads/plans-reports/2024kingcountycollisiondatareport.pdf

5. The Spokesman-Review, "Before 6 died in Tacoma wreck, officials knew intersection was deadly, lawsuit claims," June 15, 2024. https://www.spokesman.com/stories/2024/jun/15/before-6-died-in-tacoma-wreck-officials-knew-inter/

6. KOMO News, "Repeat crashes at dangerous Tacoma intersection spark calls for safety measures." https://komonews.com/news/local/tacoma-dangerous-intersection-sr509-alexander-avenue-rollover-crashes-speeding-port-of-tacoma-pierce-county-washington-state-patrol-safety-emphasis-patrols

7. NBC Right Now, "Washington State Patrol trooper killed while responding to Tacoma crash," December 2025. https://www.nbcrightnow.com/news/washington-state-patrol-trooper-killed-while-responding-to-tacoma-crash/article_b49c4103-96f9-5788-8e2a-84be76fa308b.html

8. Washington State Department of Transportation, "SR 167 Completion Project." https://wsdot.wa.gov/construction-planning/search-projects/sr-167-completion-project

9. City of Tacoma, "Vision Zero." https://tacoma.gov/government/departments/public-works/vision-zero/