Autoroutes of Quebec - Numbering System

Numbering System

Autoroutes are divided into three types – principal routes, deviation routes, and collector routes – and are laid out and numbered in a fashion similar to the Interstate Highway System in the United States. The principal Autoroutes are the major highways of the province, and have single- or double-digit numbers. East-west Autoroutes running parallel to the Saint Lawrence River (for example, Autoroute 20 and Autoroute 40) are assigned even numbers, while north-south Autoroutes running perpendicular to the Saint Lawrence (such as Autoroute 5 and Autoroute 15) are given odd numbers. Deviation and collector Autoroutes both feature triple-digit numbers. Deviation routes are bypasses intended for truck traffic to circumvent urban areas, and are identified by an even number prefixing the number of the nearby Autoroute that it bypasses (for example, Autoroute 440 in Laval). Collector Autoroutes, by contrast, are spur routes into urban areas, and are identified by an odd number prefixing the number of the nearby Autoroute that it branches off of (such as Autoroute 720, a spur of Autoroute 20 into downtown Montreal).