Autoroutes are numbered under 100 and above 400, and the conflicting range was changed.

[1][2][3] Prior to the early 1970s, Quebec's provincial routes were numbered from 1-108.

With the development and subsequent expansion of the Autoroute system, as well as an effort to simplify route connections and reduce motorist confusion.

[4] First proposed in 1966 with the intent of being implemented for Expo 67,[4] the changes did not occur until the early 1970s.

As part of the renumbering, the present blue Autoroute and green Provincial highway shields were introduced.