Alpe d'Huez is a 90-minute drive from Grenoble and about three hours from Lyon Saint-Exupéry, the closest international airport with year-round flights. Geneva is roughly the same distance. Take the A48 to Grenoble, then the N85 and N91 along the Romanche valley to Le Bourg-d'Oisans, and finally the famous twenty-one bends up.
In winter, chains or winter tyres are required on the road from Bourg-d'Oisans up. Snow ploughs work the road through the night but conditions can change quickly. Ski-bus operators (Ben's Bus, Skidoo) run direct shuttles from Geneva and Lyon airports on Saturdays. The Alpe d'Huez altiport handles light aircraft but is not a scheduled service.