SPD, City Officials Investigating SR99 Semi-Truck Collision, Reviewing Response

Seattle police and city officials are investigating a Tuesday evening semi-truck crash, and reviewing the response to the collision, which led to a nine-hour closure of State Route 99 and the Alaskan Way Viaduct

At approximately 2:21 PM, a semi-truck and trailer was traveling south on the Alaskan Way viaduct near the Atlantic Street off-ramp.  The driver of the semi-truck and trailer lost control of the vehicle causing both the semi-truck and trailer to roll over onto its side, blocking both southbound lanes of SR 99, just north of the Atlantic Street exit.

The Seattle Police Department dispatched West Precinct and Traffic personnel to the incident. The on-ramps to the viaduct were closed to any further southbound traffic and the Battery Street tunnel lights were turned on, but a number of vehicles remained stuck in a back-up north of the collision scene. Officers were able to clear the backup of vehicles from the Viaduct by turning them around and rerouting them off of SR99 using the Columbia Street on-ramp.

Lincoln Towing responded to the scene with two large tow trucks and one standard-size tow truck.

Eventually Lincoln Towing personnel were able to raise the overturned trailer. However, the load of fish in the trailer’s container had shifted, causing the truck to become unstable. At this point the trailer was upright, but still blocking all southbound lanes. Lincoln Towing determined the trailer’s cargo of would have to be off-loaded in order to stabilize the trailer.

City officials ultimately had to rely on personnel from Seattle Tunnel Partners, and used their heavy equipment to off-load a portion of the container. Once about half of the container’s cargo was removed, the trailer was deemed stable enough to be moved from the viaduct.

The viaduct was reopened at 11:35 p.m. following an approximate nine-hour closure.

The following is a timeline of events, according to SPD’s dispatch log:

  • 2:23 911 receives reports that a large semi-truck has crashed and jackknifed on the Alaskan Way Viaduct

  • 2:24 First SPD officer dispatched

  • 2:27 SPD notifies Metro and SDOT

  • 2:32 Officers approach crash scene foot because of major traffic blockage

  • 2:33 Driver removed from cab of vehicle w/head injury. Officers notify medics.

  • 2:34 Request for all southbound entrances to be blocked

  • 2:53 SPD requests “tow for tractor-trailer on side”

  • 2:59 Officers begin work to direct traffic and remove vehicles from viaduct

  • 3:04 Parking unit join effort, assist directing traffic

  • 3:08 –Lincoln towing provides 30 min ETA for 1st tow truck

  • 3:21 SDOT on-scene

  • 3:36 Metro begins work to get buses off viaduct and reroute

  • 4:05 Second tow truck arrived

  • 7:08 Trailer upright, unknown time to get it attached and moving

  • 7:50 Efforts to move trailer failed, Lincoln begins effort to drag trailer to to parking lot

  • 8:54 Lincoln advises trailer will have to be unloaded before it can be moved

  • 10:45 Trailer 30-percent unloaded, advised 60-90 additional minutes before cargo transfer is completed

  • 11:37 Viaduct reopened to traffic

The Seattle Police Department, Seattle Department of Transportation and Washington State Department of Transportation provided frequent updates on the incident throughout the evening via social media. Those updates have been collected here: