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The Seattle Times via AP, Lindsey Wasson
A Washington State Patrol photographer documents the scene after a large accident involving a truck carrying gravel Saturday, July 18, 2015, on Interstate 5 north of Seattle. Multiple people were injured in the crash and over a dozen vehicles were involved.

SEATTLE — The Washington Department of Transportation says it has no immediate plans to reevaluate the use of cable median barriers along a stretch of Interstate 5 in Mount Vernon, where a dump truck carrying gravel plowed into oncoming traffic over the weekend.

Some 27 vehicles were involved in the accident Saturday, when the truck crashed through the median and hit traffic that had been backed up while police investigated a fatal double-shooting. Investigators believe the dump truck driver may have had a medical condition that caused the crash. Seven people were injured, at least one critically.

The state has replaced some cable barriers with concrete ones over the years, notably on a stretch north of Everett where the cable barriers had failed to prevent cross-over collisions. But agency spokesman Travis Phelps says there are no barriers designed to withstand a crash of such magnitude.