A semi-trailer plowed into backed-up traffic on a Michigan highway, killing four people and injuring 17 others just before midnight Saturday, police said.

Michigan State Police troopers were stationed on Interstate 96, controlling traffic while workers installed power lines across the road, the department said in a statement.

Before the crash, “numerous” cars were stopped in the westbound lane of the highway near the junction with the M-52, police said. The work, which was being carried out by Consumers Energy, required the road to be closed for a short time, police said.

Those vehicles had just started moving again when the truck crashed into them, police said.

“It appears the driver of the semi truck did not see the stand and was unable to stop his vehicle in time,” police said. “The semi truck was in the left lane and struck numerous vehicles.”

The truck and more than a dozen other vehicles caught fire after the crash, police said.

“Seventeen vehicle occupants were transported to UM Sparrow Hospital and McLaren Hospital in Lansing for serious injuries,” police said.