The Ontario Provincial Police are investigating an overnight crash on Hwy. 77 in Leamington.
Police call it a single-vehicle collision between Mersea Road 7 and Mersea Road 6.
The lone occupant of the vehicle was rushed to the hospital with life-threatening injuries after the crash late Monday night.
The highway reopened around 5 a.m. on Tuesday.
Investigators haven't released any more information at this time.