What was the other name for Highway 401 in Ontario?

It is a highway that extends across Southern Ontario. It is the longest 400-Series Highway in Ontario and the busiest and one of the widest highways in the world.
Together with Quebec Autoroute 20, it is the road transportation backbone of the Quebec City-Windsor Corridor, along which over half of Canada's population resides.
Colloquially, the road is known simply as "The 401", spoken as "four-oh-one".