[quote=Pe
There are no trees in the desert. There are no buildings nearby the road, except at isolated towns. [/quote]

Okay, it is time to get specific. There are deserts with extensive treeless areas, but in other there is plenty of shade. The Lower Sonoran Desert - Tucson and Phoenix and the area to the west - contains a fair number of trees which provides a significant amount of shade. There are also rocky gorges and other geological features which also provide shade and shelter. Some of these are amazingly pleasant. You may or may not be able to take advantage of them. Even endless sand dunes provide some shade early and late in the day. Desert are far more varied than their depictions in B movies.