Autoroute 55 (also called Autoroute de l'Énergie north of the Autoroute 20 and Autoroute Joseph-Armand Bombardier south of it) 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 long, including concurrencies with Autoroutes 10, 20 and 40.