The police attend accidents to ensure public safety and to determine the cause.
After investigating the traffic accident, the officer makes a determination of who/what caused the accident, or who is most at fault.
If the police officer believes that one of the drivers committed a driving infraction, the officer may issue that driver a traffic ticket under the Highway Traffic Act of Ontario.
The officer does not have to issue a ticket. It is solely up to the officers discretion to lay a charge or not.
Many times, police officers issue drivers involved in accidents a Careless Driving ticket. The police officer has the option to give which ever ticket feels fit for the situation as defined in the Highway Traffic Act of Ontario.