BIRCH RUN, Mich. (AP) — A Michigan State Police trooper who died after he was struck by a vehicle while conducting a traffic stop was a 39-year-old who had joined the police agency four years ago, authorities said.

Trooper Joel Popp of the Tri-City Post is survived by his wife, Stefanie, and a young daughter, state police said.

Popp and other troopers were investigating a suspected impaired driver Wednesday night who was stopped “in a curved lane of travel” on northbound Interstate 75 in Saginaw County near Birch Run, about 17 miles (27 kilometers) north of Flint, state police said.

A vehicle driven by an 81-year-old motorist struck two patrol cars and Popp, who was outside his patrol vehicle, state police said. Popp died at a hospital, while the motorist suffered serious injuries but was expected to survive.

Popp, who enlisted with Michigan State Police in January 2020, is the 56th Michigan State Trooper to be killed in the line of duty, state police said.

“I ask that you please keep his family, fellow troopers and all whose lives he has touched in your thoughts,” Col. James F. Grady II, director of Michigan State Police, said in a news release early Thursday.