The investigation continues following Thursday afternoon's multi-car pileup on westbound Hwy. 402 near Watford.
Four people were taken to hospital. Three were listed in serious condition.
The chain reaction crash involving four tractor trailers and seven vehicles occurred just after 1pm in whiteout conditions just east of Nauvoo Rd.
Police had to deal with 100 other vehicles stuck on Hwy. 402 behind the crash scene.