In Ontario, Canada, a woman was killed last week when a set of wheels broke loose from the rear of a tractor-trailer, bounced across the median and smashed into her car.

The incident happened on the Queen Elizabeth Way near Oakville, west of Toronto.

Under Ontario law, owners and operators of heavy trucks are absolutely liable for accidents involving detached wheels, even if they can show they took steps to prevent the accident.

Violators face fines of up to $50,000.