This time of year the asphalt/concrete/rocks may be very hot on their pads. Our G.Shepards would try to run to cooler dirt at rest areas, We went so far at to pour water on the asphalt where they had to stand to enter/exit the truck. It may look funny but kids socks, of the right size for dogs, helps with the heat but not the cockle burs.
That brings up cockle burs another bane of dog feet in the SW. All you can do is watch the ground and keep them out of the worst patches. Or spend money for dog booties which I think are a pain to put on and our dogs hated them, but they do work.