A school bus driver has died and four children have been taken to hospital with minor injuries following a school bus crash off the westbound lanes of Highway 401 in London, Ont., Ontario Provincial Police (OPP) announced Sunday.

The crash and the ensuing investigation closed the highway’s westbound lanes between Veteran’s Memorial Parkway and Highbury Avenue for several hours, with police reopening the roadway just after 4:30 p.m.

The single-vehicle collision happened around 9:40 a.m., according to OPP Const. Steven Duguay, who said the bus veered off the highway before tipping over and coming to a stop.

“We’ve got 42 passengers on board that school bus, four of which were transported to the hospital with minor injuries,” Duguay said.