<P> King 's Highway 401 , commonly referred to as Highway 401 and also known by its official name as the Macdonald -- Cartier Freeway or colloquially as the four - oh - one , is a controlled - access 400 - series highway in the Canadian province of Ontario . It stretches 828.0 kilometres ( 514.5 mi ) from Windsor in the west to the Ontario -- Quebec border in the east . The part of Highway 401 that passes through Toronto is North America 's busiest highway , and one of the widest . Together with Quebec Autoroute 20 , it forms the road transportation backbone of the Quebec City -- Windsor Corridor , along which over half of Canada 's population resides and is also a Core Route in the National Highway System of Canada . The route is maintained by the Ministry of Transportation of Ontario ( MTO ) and patrolled by the Ontario Provincial Police . The speed limit is 100 km / h ( 62 mph ) throughout its length , unless posted otherwise . </P>
<P> King 's Highway 401 , commonly referred to as Highway 401 and also known by its official name as the Macdonald -- Cartier Freeway or colloquially as the four - oh - one , is a controlled - access 400 - series highway in the Canadian province of Ontario . It stretches 828.0 kilometres ( 514.5 mi ) from Windsor in the west to the Ontario -- Quebec border in the east . The part of Highway 401 that passes through Toronto is North America 's busiest highway , and one of the widest . Together with Quebec Autoroute 20 , it forms the road transportation backbone of the Quebec City -- Windsor Corridor , along which over half of Canada 's population resides and is also a Core Route in the National Highway System of Canada . The route is maintained by the Ministry of Transportation of Ontario ( MTO ) and patrolled by the Ontario Provincial Police . The speed limit is 100 km / h ( 62 mph ) throughout its length , unless posted otherwise . </P>
what is the widest highway in north america
what is the widest highway in north america
Highway 401
Highway 401