A Toronto woman is dead and three other people injured after a crash on Highway 401 in the city early Saturday, police say.

The crash occurred in the eastbound express lanes of Highway 401 near Islington Avenue. Ontario Provincial Police were called to the scene around 1:15 a.m.

The woman, 32, was a passenger in a vehicle and died on the way to hospital, according to Sgt. Kerry Schmidt, spokesperson for the OPP's Highway Safety Division.

Next of kin have been notified.

Schmidt said police are investigating whether the vehicle transporting the woman was an Uber. Officers are expecting to question the driver.

"We will determine that throughout the course of the day," Schmidt said on Saturday.

Police say traffic had slowed in the area due to construction. Three vehicles were involved in the crash. (Jeremy Cohn/CBC)

The woman was travelling with her husband. He and the driver suffered serious but non-life-threatening injuries in the crash.

Police looking at all factors in rear-end crash

Traffic was slowing in the eastbound express lanes due to construction ahead when the vehicle transporting the woman and her husband was unable to slow down in time, Schmidt said.

It crashed into another vehicle and pushed that vehicle into a third vehicle, he said. The third vehicle was practically stopped.

Police are considering whether speeding, distracted driving, human error or mechanical failure played a role in the crash.

"It was a rear-end collision," he said. "It was a violent crash."

Toronto paramedics rushed the woman to a trauma centre but she was pronounced dead before she arrived. The driver, the woman's husband and another person from another vehicle were taken to hospital.

Police closed the highway as officers investigated but all lanes have been reopened.

Anyone who may have witnessed the crash or who has relevant dashboard camera video is urged to call the OPP.