What are the problems of road transport in mountainous, desert and flood prone regions?

Explanation

Road transportation depends heavily on the physiography of nature.
Mountainous regions: In mountainous regions, irregular terrain makes road construction difficult as cutting through the mountains while construction is not only costly but also dangerous. Also frequent landslides make the roads unfit for use.
Desert regions: In desert regions, laying down of roads is not easy las sand does hannot provide with a strong base for construction of roads.
Flood prone regions. In flood prone regions, roads are frequently flooded, hence they cannot be used and remain unfit for use