It varies widely from State to State, and it is never more evident as when you cross a State border on one of the Interstate highways. The sudden change in road quality can be dramatic. There is also little correlation between road quality and the amount of money spent per kilometer on literally the same stretch of border-crossing highway -- the poor quality side of the border may be spending several times what is being spent on the good quality. Some States have very nice highways that are built and maintained at modest cost.

The high variance in road quality and cost is a very visible example of how varied the effectiveness and efficiency of individual State governments can be in the US.