A single-vehicle rollover on the eastbound Highway 401 east of Furnival Road closed the roadway for several hours on Tuesday evening.
An eastbound government vehicle reportedly lost control around 5:30 p.m. near Mile Marker 130.
Provincial police say the vehicle left the road, entered the ditch and rolled over.
The driver was transported to Victoria Hospital in London with serious injuries.
Elgin County OPP have closed the road between Rodney and West Lorne as they investigate the crash.
The OPP Technical Collision Investigation Team was also called in to assist with the investigation.
The highway was expected to reopen around 10 p.m.