BASIC PRINCIPLES

Much the best-known feature of Roman roads is their straightness. Over long distances this is not, of course, by any means invariable. In hilly terrain the route necessarily meanders in search of reasonably gentle gradients, and although in such cases the engineer evidently used instruments to achieve a succession of short straight alignments he must have relied overall, as he did in setting out aqueducts, on his eye for the country. Nor, very probably, did early Roman roads follow such straight courses as did later ones. It seems likely that the first routes out of Rome, built in the wake of conquest and traditionally beginning with the Via Appia of 312 BC, were quite basic in alignment and structure and were merely improvements of existing trackways. In just the same way, when Vespasian's army advanced into Galilee in AD 67, ‘road-makers straighten bends on the highway, level the rough places and cut down woods that are in the way, so as to spare the troops the fatigue of laborious marching’. The origin of straight alignment and solid structure is often ascribed on the basis of Plutarch's biography to C. Gracchus and his laws of 123 BC.