The OPP say they're investigating a crash Monday, on the Eastbound 401, as a possible case of road rage.
The three vehicle collision injured five people including a 17-month-old baby girl. She remains in critical condition.
Sgt. Kerry Schmidt says it began as a minor, two vehicle crash, "followed by an unexpected massive collision by a third vehicle that approached from behind."
One of the drivers, a 59-year-old Toronto man, has been arrested. He'll be charged with two counts of dangerous driving causing bodily harm.