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SEATTLE, King County, Wash., Oct. 17, 2026 — A three-vehicle rollover crash blocked lanes on northbound Interstate 5 near downtown Seattle on Thursday morning, October 15, slowing traffic close to Mercer Street and Denny Way.
The Washington State Department of Transportation said the crash happened at about 9 a.m. just north of Mercer Street, near milepost 167, and blocked the three right lanes of northbound I-5. The Washington State Patrol described it as a three-car rollover collision and said the right two lanes were blocked as crews worked the scene.
Seattle Fire Department crews responding to northbound I-5 at Denny Way found multiple vehicles involved, including one that had rolled onto its roof. Fire officials said the occupants of that vehicle got out on their own before crews arrived. State troopers said one person was reported injured with head pain as emergency responders reached the scene.
By 9:14 a.m., Seattle Fire said three patients were being evaluated and that all were listed in stable condition, with one confirmed injury. The department said the response was being scaled back shortly after. The cause of the crash has not been released and remains under investigation.
We wish the injured a complete and speedy recovery.
More on Crashes in Seattle, WA
This multi-vehicle crash happened at Mercer Street and Denny Way in Seattle, WA. We cover crashes across King County as they're reported, and you can browse the latest in our King County accident reports.
Frequently Asked Questions
What makes a vehicle roll over in a crash?
Rollovers typically happen when a vehicle's momentum shifts sideways faster than its tires can hold, usually after a sharp steering move, a sideswipe, or striking a curb or another car at an angle. Higher-profile vehicles are more prone to tipping than low, wide ones.
Are some roads more likely to see rollover crashes?
Rollovers happen more commonly on roads with curves, uneven lanes, or heavy merging and lane-change activity, where sudden steering corrections are more common. Dense urban freeways with closely spaced on-ramps and off-ramps, like stretches of I-5 through downtown Seattle, see frequent lane-change conflicts that can lead to this type of crash.
What injuries are typical in a rollover crash?
Occupants can suffer head, neck, and spine injuries, along with cuts and bruising, especially if they're thrown against the roof or window as the vehicle turns over. Seatbelts and airbags cut down on the severity of these injuries considerably.
What should someone do after being in a rollover crash?
Get checked by paramedics even if injuries seem minor, since head and neck pain can take hours to show up fully. Report the crash to police and your insurer, and keep any medical paperwork from the scene.
What to Do After a Rollover Crash in Seattle, WA
If you're involved in a rollover, stay as still as possible until you can assess whether you're hurt, then try to exit the vehicle carefully if it's safe to do so. Call 911 and wait for Seattle Fire or state troopers to clear the scene before moving around near live traffic lanes. Even if you feel fine, see a doctor within a day or two, since adrenaline can mask pain from neck strain or a concussion. Take photos of the vehicles and the roadway if you're able, and get the names and contact information of anyone else involved or nearby. Keep copies of any fire department or State Patrol reports, as they'll help with insurance claims down the line.
