PAW PAW TOWNSHIP, Mich. (AP) — Authorities say an ambulance driver was injured in a collision involving a semi-truck in southwestern Michigan.

The crash happened early Tuesday in Van Buren County’s Paw Paw Township and prompted authorities to close a stretch of Michigan highway 51 as crews responded. The roadway has since reopened.

The sheriff’s office says the truck rolled over after hitting the ambulance. The driver of the ambulance had what were described as non-life-threatening injuries. The ambulance wasn’t carrying a patient.

The truck driver wasn’t injured. The cause of the crash is under investigation.