Three people travelling in a classic 1948 Chevy were killed when mechanical trouble with a tire set off a dramatic chain of events that resulted in the vehicle bursting into flames and crashing on the side of Highway 407 in Brampton Sunday.

It happened in the westbound lanes of the highway near Mississauga Road at around 3 p.m.

According to Ontario Provincial Police, the vehicle appears to have encountered a mechanical defect in the right rear tire, causing it to lose control and veer into the left inner lane.

“As a result of that, a coach bus which was travelling westbound t-boned the Chev,” OPP Sgt. Vince Idzenga told CP24. “As a result of that impact, the Chev burst into flames and was redirected into the right shoulder.”

The burning vehicle then rolled over, coming to rest in a ditch beside the highway.

Two passersby noticed the crash and rushed to help, dragging two male victims from the burning car. However they were unable to free the third victim.

Peel Regional Paramedic Services initially said two of the occupants form the Chevy were declared dead at the scene, while another person sustained critical injuries. However a short time later paramedics said that all three occupants of the vehicle had been declared dead. None of the victims have been identified so far.

The driver of the coach bus and all 49 passengers on-board were uninjured and the bus sustained only minor damage, Idzenga said.

Idzenga said several witnesses gave similar accounts of the crash to police and pointed to trouble with the Chevy’s wheel as the cause.

“There is no evidence of any speed issues or any other factors,” Idzenga said. “It just appears unfortunately that the mechanical issue with the tire was the primary causation factor in this collision.”

According to witnesses, the vehicle appears to have burst into flames almost immediately after colliding with the bus, Idzenga said.

Images from the scene showed multiple ambulances and fire vehicles on the highway and video sent to CP24 from passersby showed a vehicle burning on the side of the highway prior to being extinguished by firefighters.

Forensics officers and collision reconstruction specialists are working at the scene to try to gather more evidence to understand the crash.

Idzenga said police are still looking to speak with anyone else who witnessed the collision and urged any possible witnesses to contact police at 905 841-5777.

All westbound lanes of Highway 407 are closed between Mavis and Mississauga roads as police investigate.

The on-ramp to the westbound lanes of Highway 407 from Mississauga Road have been closed as police investigate the deadly crash.