Police have reopened the ramp from Highway 404 to Highway 401 eastbound, as well as both the northbound and southbound ramps from Highway 427 to Highway 401.
Two separate, early morning tractor-trailer rollovers in opposite ends of the city, closed the interchanges for hours.
For most of the morning there was no access to Highway 401 from Highway 427 southbound or northbound after a tractor-trailer carrying a load of plastic stripping rolled over just before 4 a.m. It took until 11 a.m. to get things moving normally again.
One of the factors that delayed the reopening of the ramp was that the load had to transferred to another vehicle before the truck could be righted.
In the east end of the city access to the 401 eastbound was blocked for hours because of another tractor-trailer rollover.
That truck was carrying auto parts and rolled over at about 3 a.m.
OPP Sgt. Dave Woodford said police will be looking at "speed on the ramps and the loads on [the trucks]," as possible causes in both accidents.
Investigators will examine "whether the loads shifted or not. So two big concerns, you know, when we deal with truck rollovers," he said.
The Highway 404 ramp reopened at about 8:15 a.m.