A man in his 50s suffered "serious head injuries" Friday morning and was transported to Sunnybrook Hospital in Toronto by air ambulance after what police called a "suspected road rage incident."
The altercation started in the Town of Bradford West Gwillimbury, according to police.
Officers with the South Simcoe Police Service were called to the intersection of the 9th Line and 5th Side Road around 7:20 a.m. about a confrontation between two drivers.
Police say one of the drivers suffered serious head injuries and was transported to Upper Canada Mall in Newmarket where he was airlifted by Ornge Air Ambulance to Sunnybrook.
The two vehicles involved are a 2010 Grey Dodge Dakota pickup truck and a red 2002 Mazda Protege 5.
Police say the two vehicles "were following each other" eastbound on 9th Line and ended up at the intersection of 9th Line and 5th Side Road.
Reports say the driver of the Mazda then exited his vehicle and approached the pickup truck.
Police are appealing for witnesses who may have seen any portion of this incident or captured it through dashcam footage to contact them.
Officers from the Criminal Investigation Bureau and Traffic and Marine Unit are continuing their investigation to determine what happened.