A51 autoroute
The A51 autoroute is a partly completed motorway in southeast France. It currently exists as two sections separated by a gap of approximately 85 km, the northern section sometimes referred to as the A51N.
It is the long-term project to connect Marseille to Grenoble via Aix-en-Provence, the Durance Valley and the Hautes-Alpes department, providing a high-capacity alternative to the heavily used A7 following the Rhône valley.