Twenty-one hairpins at 8.1 per cent
The final section has an identity in numbers, which is rare. The tourist office gives 13.8 kilometres of climb on the RD211, an average gradient of 8.1 per cent, and 21 numbered hairpins up to the resort, in the Grandes Rousses range. Before that, the route uses the A480 and then the RD1091 from the valley.
Those numbers are not decoration. An 8 per cent average over nearly fourteen kilometres, with tight bends, forces slow steady driving, especially loaded. Time lost on that climb is not recovered, it is planned for. Which is why a transfer here is built backwards from the arrival time you want, all the way down to the departure time on the coast.
In summer the same road can close: the resort reports access closures during the major sporting events it hosts.
Equipment checks happen on the approach
The official question page is blunt on two counts. The hairpin road is cleared of snow regularly, but it remains a mountain road. And equipment checks are carried out regularly on the approach to the resort.
That is the best possible reason to equip a vehicle between November and March: not a precaution in principle, but a check the resort itself announces. The commune also appears on the Isère prefectoral list, where the period runs from 1 November to 31 March.
Once in the resort, the same page pushes visitors to leave the car: it points to the free urban lifts Huez Express, Alpe Express and Télécentre rather than to driving. Those are three public, named landmarks that are easy to give a guest.
When the car stops being the right answer
Let us be plain about the limits. For one or two people travelling light from the Riviera, a full day on the road compares badly with a rail journey to Grenoble followed by a short climb. The arithmetic leans clearly the other way.
The road wins back on three conditions: a group, bulky equipment, or an arrival that connects to no timetable. We say so in both directions, including when it costs us the job. The fare is confirmed to you in writing before departure, tolls and fuel included.