Damariscotta police have identified the Boothbay man who died Monday when his pickup truck collided with a tractor trailer near the intersection of U.S. Route 1 and Business Route 1.

Shannon Gilbert, 76, was killed after his 2007 GMC 1500 collided with the tractor trailer operated by Jason Spear, 45, of Rockport, Chief Ronald Young said in a statement Tuesday. Spear was driving a 2005 Peterbilt tractor trailer.

The cause of the crash, which was reported around 10 a.m., remains under investigation by the Lincoln County Sheriff’s Office and the Maine State Police Commercial Vehicle Division.