A driver was killed when he was hit by a truck while walking on the Massachusetts Turnpike in Palmer early Sunday morning, police said.

The driver was hit about 3:35 a.m., Massachusetts State Police said. He had parked his car where the highway passed over North Main Street and is believed to have walked onto the Turnpike.

Police didn't initially identify the victim, belived to be a Palmer resident, or give his age.

The driver of the truck, which was carrying a heavy-duty excavator, pulled over after hitting the pedestrian between the center and left lanes of the the Boston-bound side of the highway, police said. He called 911 and was not hurt.

The crash remains under investigation. Police didn't say what they believe led to the crash.