This features another example of a subject popular at the time: highway construction in the intermountain west. This image not only shows the sinuous path of the legendary Highway 66 through the Arizona desert, but also, at the right, a long turnout to the top of a hill. This was no doubt graded to allow travelers a chance to stop and take pictures from the hilltop.
This card has no description on the back, just a stamped indication of where to write your address and message. It likely dates from the 1940s.