Early on Saturday, police were conducting a R.I.D.E. check on the off-ramp of the QEW at Dundas Steet West.
At about 6:25 a.m., a vehicle failed to stop, sparking a police chase, the Ontario Provincial Police said in news release.
Officers soon called off the pursuit, fearing members of the public might get hurt, police said.
The other car later crashed at Hurontario and Dundas streets.
EMS crews transported the driver to hospital, where he was pronounced dead.
The provincial Special Investigations Unit (SIU) has been called in to probe the single-vehicle crash.
The SIU is called in whenever police officers are involved in incidents in which someone has been seriously injured, dies or alleges sexual assault.