Autoroute 55 is an important north–south Autoroute and the only one running in that direction in central Quebec. It is the longest north-south Autoroute, beginning as the continuation of I-91 at the Canada–United States border near Stanstead and continuing to Shawinigan, where it downgrades to Route 155. The total length of A-55 is currently 247 km (153.5 mi) long, including concurrencies with Autoroute 10, Autoroute 20 and Autoroute 40.

Autoroute 20 is a Quebec Autoroute, following the Saint Lawrence River through one of the more densely populated parts of Canada, with its central section forming the main route of the Trans-Canada Highway from the A-25 interchange to the A-85 interchange. At 585 km (363.5 mi), it is the longest Autoroute in Quebec. It is one of two main links between Montreal and Quebec City; the other is the A-40.