The eastbound 401 collector lanes were closed between Avenue and Yonge for about four hours early Tuesday, as police investigated a deadly fall.
A man fell to his death around 2 a.m., to a wooded area below the highway.
The province's Special Investigations Unit says the man was reportedly walking along the highway.
They say he ran from a police officer, across four lanes of traffic, and fell through a gap between the express and collector lanes.
He was pronounced dead at the scene.
The SIU investigates reports of death or serious injury involving police.
With files from Tiffany Hendsbee