If you drive towards the upper valley through Sölden, the glacier road branches off to the right at the very end of the village. On spectacular bends and steep ascents you will quickly gain altitude on this connecting toll road (free of charge with a valid skipass).
An average gradient of 11% awaits drivers on the 13 km long route to Rettenbach Glacier. If you also want to visit Tiefenbach Glacie you have to cross the mountain through Europe's highest road tunnel, passing also the highest point of the glacier road (2830 m).
If the air gets too thin, nobody gets out of breath when looking for a parking space: ample parking is available for cars and coaches at both glaciers. Only a ride on the free glacier skibus is even more relaxing.