All northbound lanes on Interstate 405 in Bothell have reopened after a Department of Transportation employee was struck Wednesday morning while responding to a previous collision.

Both drivers were taken to the hospital for non-life-threatening injuries, according to Rick Johnson, a spokesperson for WSDOT. The incident occurred around 10 a.m. just south of Highway 527.

The two left northbound lanes were closed until 3 p.m., causing traffic congestion stretching six miles.

The driver of the van is under investigation for suspected impairment, Johnson said. The driver ran through cones marking a closed lane before striking the incident response team vehicle.

According to WSDOT, the worker has been previously injured in a work zone crash.

“Just doing his job trying to keep people stay safe on the highway,” the agency posted on Twitter Wednesday. “If you’re going to operate a vehicle, be sober, be alert, be focused.”