ROCKPORT -- Police are investigating an accident that left a Rockland man in critical condition this morning.

Robert King, 51, of Rockland, was driving north on Route 1 when he crossed into the southbound lane and ran into a ditch, said Police Chief Mark Kelley. The Ford F-150 struck a rock ledge outcropping and flipped onto its roof, coming to rest in the southbound breakdown lane, Kelley said.

King did not have any passengers and no other vehicles were involved in the accident, which occurred about 7:30 a.m.

King was taken to Penobscot Bay Medical Center and then by helicopter to Eastern Maine Medical Center in Bangor. The hospital said no information on King was available.

Kelley said it appears that a medical condition may have been at the root of the accident.