One still has to wonder why they selected 136, and not something that was actually available.
As an east-west highway, there was no available number in, or around the greater Montreal area.
- 132: Used on South Shore of the St-Lawrence River.
- 134: Used on Jacques-Cartier Bridge, and Taschereau Blvd. from Longueuil to Delson.
- 136: Used in Quebec city, but not in Montreal.
- 138: Used on Sherbrooke St., in Montreal, north of the QC-136/A-720.
- 140: Not used, because there's a highway 40.
- 142: Would be available, but wouldn't fit because the highway we want to number is between 134 and 138.
Normally, highway numbers climbs from south to north (and from west to east); QC-132 is south of 134, that is south of 136, etc. They also keep numbers that finishes with a 0 - or with a 5 in case of north-south highways - as a continuity at the end of an Interstate-standard highway; QC-155 continues at the end of A-55, for example. But I say "normally" because the MTQ numbering system is full of exceptions.