Two people are dead and three others are injured after a mid-afternoon crash on Highway 401.
The accident occurred over the lunch hour Sunday on the highway's westbound express lanes near the Warden Avenue exit. Two vehicles were involved in the crash.
OPP Const. Dave Woodford told reporters at the scene a car, believed to be a Subaru, was pulled over on the shoulder with its four-way flashers on when a second vehicle smashed into the back of it.
The second car, a Lexus with New York state licence plates, was travelling at a speed over 100 kilometres per hour at the time of the impact, Woodford said.
The driver of the Subaru, a 71-year-old man from Mississauga, was pronounced dead at the scene. There were no passengers in his car.
The driver of the Lexus, a 21-year-old woman, has been charged with two counts of dangerous driving causing death.
Her father, sitting in the backseat of the Lexus, suffered critical injuries in the crash and died in hospital.
Her mother, also sitting in the backseat and her sister, sitting in the front seat, suffered minor injuries.
"It's devastating," said Woodford. "You hate to see anyone lose their life for any reason. It's a big impact on a lot of people."
Woodford said police are looking to speak with witnesses. Authorities are trying to determine why the driver of the Lexus also pulled onto the shoulder.
"That's what we're going to find out, why she went onto the shoulder and hit the back of the vehicle travelling at such a speed," he said.
The express lanes remain closed, from Brimley Road to Warden Avenue, as police conducted their investigation.
Traffic travelling along the eastbound lanes of the highway was snarled as people slowed to take a look at the accident.
The section of the highway remained closed until early Sunday evening.
Meanwhile, police in Mississauga are still investigating the cause of a serious crash on Derry Road Saturday night.
Three cars collided at around 6 p.m. near Hurontario Street.
Emergency crews had to use the Jaws of Life on each car.
One person was airlifted to Sunnybrook hospital in critical condition.
With a report from CTV Toronto's Naomi Parness
