From Sisteron, the route first follows the Durance valley, with the citadel and limestone cliffs still behind. The road then grows quieter through Laragne-Montéglin and Serres, tracing the wide Buëch valley past pale slopes, small villages and early views towards the Dévoluy mountains. Later, the climb leads up to the Col de la Croix-Haute. Beyond the pass, the Trièves opens out with views of the Vercors and Mont Aiguille. Before Grenoble, the landscape becomes more urban, but the mountains stay close.
