Classicly

A road system, once established, develops at its points of concentration the nerve centres of the society it serves; and we remark that the material rise and decline of a state are better measured by the condition of its communications—that is, of its roads—than by any other criterion.

The construction, the trace, and the whole character of the Road change with new social needs and habits, with the facilities of natural science, their rise and decline. But this perpetual change, which affects the Road as it does architecture and every other work of man, is specially marked by certain critical phases, one of which, as I said at the opening of this, we have now entered. There are moments in the history of the Road in any society where the whole use of it, the construction of it, and its character have to be transformed.