A 13-year-old was driving his parents' SUV when it crashed through a fence onto Highway 403 in Oakville, Ont., on Saturday morning, smashing head-on into the centre median.
The driver and two passengers, one aged 14 and the other 16, were all hurt in the collision and transported to a children's trauma centre for treatment, said Halton police.
The 14-year-old remains in life-threatening condition, while the other teens involved are in stable condition.
All three of the teens are from Oakville. Police did not provide any further details about them.
Officers were initially called to the crash scene, in the westbound lanes of the highway approaching Trafalgar Road, at 4:45 a.m. ET.
The driver had been southbound on Eighth Line, which runs perpendicular to Highway 403, when he lost control of the SUV. The vehicle went through a chain link fence and onto the highway, before slamming head-on into the centre median.
Due to the severity of the injuries, the collision reconstruction unit took charge of the investigation, Det.-Const. Chris Heffernan said in a news release.
"Police continue to investigate the collision and no charges have been laid against the driver at this time," he said. Police believe speed and inexperience were both contributing factors in the collision," Heffernan said.
The westbound lanes of Highway 403 were closed for about four hours as police investigated the crash. All lanes have since reopened to traffic.