A recent (1957) survey of the central section of the Valeria by the Dutch scholar C. C. Van Essen illustrates the methods and results of archaeologists working in the field with topographical problems. Faced with the palimpsest of more than two millennia overlying the road he wanted to trace, Van Essen paid particular attention to such roadmarks as Roman milestones; ancient tombs (which regularly lined Roman roads in the vicinity of towns); supporting walls, in Roman headers-and-stretchers; rock-hewn causeways; bridges, where Roman materials and workmanship can be distinguished from modern (as has been recently done for the bridges of the Via Flaminia by Michael Ballance of the British School at Rome; there the striking thing is the predominance and good quality of the work done under Augustus, who had a vested interest in assuring efficient communications with his veterans dispersed in colonies in north Italy). Stretches of ancient pavement are rare on the Valeria, having been destroyed by medieval and modern resurfacing, by the plow, and by torrents and earthquakes, but the trench in which it was bedded can often be distinguished on air photographs. What struck Van Essen chiefly was the frequency with which the ancient Via Valeria would run straight on, with steep gradients, where the modern road resorts to sweeping curves or hairpin bends. Ancient vehicles, the heaviest of which were perhaps only a quarter the weight of a modern light European car (Roman wagon, perhaps 440 pounds; Volkswagen, 1650), and scarcely ever carried loads of over 1100 pounds, would be less troubled by steep gradients than a modern heavy truck. Even so, at Tagliacozzo, about six miles on the Rome side of Alba Fucens, the grade is so steep that Van Essen supposes the ancient inhabitants hired out oxen to help the straining horses on the upslope. Van Essen noted that the telegraph lines, following the comparatively straight course of the ancient road, often gave a clue to its presence. The ancient sixty-eighth milestone of the Valeria, found, as we saw, within the walls of Alba Fucens, provides a good comparison of the respective lengths of the ancient and the modern roads. Since the Roman mile (4861 English feet) was slightly shorter than the English, sixty-eight Roman miles corresponds to slightly over sixty-two English miles, whereas the modern Via Valeria covers about 113 kilometers, or approximately seventy miles, to reach Alba.