Coastal road, especially one running along a cliff face.
A road built along a coast and especially along the face of a cliff.

(French “mountain ledge”) La Grande (Great) Corniche is a road with superb alpine and coastal scenery, built between Nice and Menton, S France, by Napoleon; it rises to 520 m/1,700 ft. La Moyenne (Middle) and la Petite (Little) Corniche are supplementary parallel roads, the latter being nearest the coast.