The M73 distributes traffic between three of Glasgow’s most important approaches, and provides a key link in the north-south drive through Scotland’s central belt, but its main purpose is to help people avoid Glasgow.
It crosses cattle grids and untamed moorland, it climbs 1-in-4 hills and plummets through hairpin bends, it runs single-track through woodland and historic villages. It's rugged and beautiful. Is it really the A39?