Speed and alcohol are considered factors in an ATV and lawnmower collision that sent a West Carleton resident to the Ottawa Hospital, Civic campus with serious head injuries, police said.

The collision took place early on Sunday near Mohrs and Kinburn Side roads in West Carleton, about in rural west Ottawa, when the ATV hit the back of the riding lawnmower, police said.

The ATV driver was not wearing a helmet and was thrown from the vehicle, while the lawnmower driver was uninjured.

An investigation continues.