CHICAGO (CBS) — A truck driver was killed when he got out of his vehicle on the shoulder of the Dan Ryan Expressway, and another truck hit him Friday morning.

Illinois State Police said 32-year-old Augstin Perez, of Berwyn, stopped his 2000 Freightliner semi-trailer truck on the right shoulder of the inbound local lanes of the Dan Ryan near 31st Street around 5 a.m.

Another truck, a Volvo semi-trailer, struck Perez as he was in the far right lane of the expressway, police said. Perez was pronounced dead at the scene.

It was not immediately clear why Perez stopped and got out of his truck.

The other driver, a 53-year-old man, stopped at the scene and was taken to Mercy Hospital.

The local inbound lanes were closed until about 9:15 a.m. while police investigated the crash.