From CP24:
York Regional Police have confirmed that an officer who was struck by a vehicle during a traffic stop Tuesday morning has died of his injuries.
The fatal collision occurred on Highway 48, which is closed in both directions between Mount Albert Road and Davis Drive, east of Newmarket.
Police said the officer was struck by a vehicle while he was conducting a traffic stop on Highway 48, near Herald Road, in East Gwillimbury at about 4:45 a.m.
The officer was standing outside of his vehicle when he was struck.
Footage from Chopper 24 showed a light-coloured van off the highway in a field. The van appeared to have damage to its front end.
It's believed one male has been taken into custody by police.
Officers have set up a wide perimeter. A canine unit is scouring the area for any additional suspects.
Ontario Provincial Police are involved in the investigation, as well. OPP said Highway 48 is expected to be closed between Mount Albert Road and Davis Drive for most of the day.