A boy of a year and a half was hit by a vehicle in St. Clements shortly after 10 am on Sunday.
The child was taken to Grand River Hospital and then taken to the Hamilton General by Ornge Air Ambulance.
Police say he believes his father hit the boy.
Traffic spent hours at the St. Clemens court today, rebuilding the events leading up to the crash.
The child suffered a head injury, but the extent of his injuries is unknown.