Police said in a news release that the collision happened around 1:30 a.m. Sunday near Islington Avenue.
The release said that a white 2015 Audi R8 with licence plate CTPV512 was heading south on Highway 427 “at a high rate of speed,” and then went east on the Gardiner Expressway.
The Audi then hit the back of a grey Nissan, and the Nissan struck the north guardrail and flipped onto its roof, police said.
The woman who was killed was a passenger in the Nissan. She was taken to hospital with life-threatening injuries and later died.
The driver of the Nissan, a 61-year-old man, suffered non-life-threatening injuries.
Police said the Audi stopped on the right shoulder of the highway and the driver fled the crash scene on foot.
The news release said multiple motorists stopped to help and some took video of the scene after the crash.
Police are now looking to speak to any witnesses or anyone with video footage in relation to the incident.
Police also said they identified 30-year-old Kalyan Trivedi as a person of interest and are looking to speak to him.
“Anyone that may have any information regarding the whereabouts of Kalyan Trivedi on Saturday, October 2, 2021 or Sunday, October 3, 2021 are also asked to contact police,” the release said.