Churchill and northern Manitoba needs a 2-lane highway (currently served by only a railroad for part of the way) but no more.
Except in the urban areas, a 4-lane freeway is adequate along the corridor north of Kansas City to Winnipeg. The traffic counts range from about 5,000 to 20,000 along there.
It's tough to maintain a real road in the frozen North. I took a trip to Moosonee long ago, and the last miles were by train, and Churchill is further North and really in the tundra ....................... FRegards