ROMAN TRACTION SYSTEMS

GEOGRAPHY AND ROADS

The network of roads connecting various parts of the Roman Empire was one of the crowning achievements of Roman engineering and stretched for 85,000 km. (53,625 miles) under Diocletian¹. Large portions of this network were paved with brick making for fast movement on land. The emphasis was on speed – the roads were designed to speed government officials, and couriers, as well as the military; they were only secondarily for commercial and private use². Nevertheless the main roads provided a hard surface for wagons and carts, although long-distance trade, wherever possible, used ships as for when transporting grain from Alexandria to Rome. Local and infra-city and inter-city commerce was undoubtedly done by wagons, pulled either by oxen, horses, or mules, and pack animals. It goes without saying that it requires more effort on the part of the object, be it human, animal or machine, to pull a load up hill, on dirt roads, through mud or sand than it does on a smooth, straight paved roads³.

The roads were first "furrowed out" then filled with bedrock, before being paved. Attention was paid to curbing. Nor did Roman roads necessarily go around obstacles. In many cases inclines were cut off through hilly country and bridges were built where needed⁴. Throughout much of the former Roman Empire cylindrical milestones still survive whose inscriptions often boast of the repairs carried out⁵. Obviously such a highway system was very expensive and officials were concerned about traffic which could degrade the road surface.

So important was speed and cost of repair to the Roman Romans that weight limits were codified by the Codex Theodosianus.

The weight limits specified in De Cursu Publico are⁶:

Angaria – 1,500 Roman lbs. – 492 kg
Raeda – 1,000 Roman lbs. – 330 kg
Currus – 600 Roman lbs. – 198 kg
Vereda – 300 Roman lbs. – 99 kg
Birota – 200 Roman lbs. – 66 kg

But when Lefebvre des Noëttes read this code he immediately believed that the numbers represented in reality the MAXIMUM load of the vehicles and for proof pointed to his own 1910 experiment in which he concluded that "it is impossible practically to surpass the maximum limit imposed by De Cursu Publico..."⁷. This idea has since been repeated by others without critical evaluation⁸. For a long time this error enshrined the false theory that a team of horses using Roman harness could only pull a maximum of 500 kg (a little over 1,000 lbs.) before "choking".

However, without discussing the real load limits, a careful reading of De Cursu Publico indicates that this was the maximum allowed by the law, but in no way represented the maximum possible. A section of the code specifically stated that these numbers DO NOT represent the OUTER LIMITS of what was possible.

We shall allow nothing beyond a thousand pounds of weight to be placed on vehicles, and thus the couriers⁹ shall be satisfied that We grant them the right to transport thirty pounds on their horses. Therefore, if it should be established that any load exceeds this measure, the excess must be confiscated to the fisc. at the expense of the person who committed the offense against the law. I. We also decree that it shall be sanctioned that the use of enormous vehicles shall entirely cease, so that if any workman should suppose that he might make a vehicle beyond the norm that We have prescribed, he shall not doubt that if he is free, he must undergo the punishment of exile; if a slave, perpetual punishment by labor in the mines¹⁰.

The Theodosian Code also charged special officials with the "the enforcement of this regulation, so that they may always inspect the size of the vehicles and the amount of the loads and may not allow anything to be done contrary to the law"¹¹.

No rational person can believe that such limits would have been codified into lad if there had existed a physical impossibility to exceed them. Yet Lefebvre des Noëttes and his supporters do just that. They have dismissed those parts of the law which did not agree with their positions – without ever doubting that those positions could be wrong.

So why did the Theodosian Code set these limits? Some obvious reasons come to mind: 1. The network of Roman roads were designed to move Roman Armies and Imperial officials swiftly to inland destination points. 2. Heavily loaded vehicles will in time cause road surfaces to deteriorate necessitating expensive repairs¹². Not only that, overloaded vehicles themselves would get damaged, thus incurring expensive repairs. Even in Ancient Greece there was concern about damage to roads and wagons.

We must also have spare wood for both the chariots and the wagons. For by necessity many parts are worn out by continual use. We must also have most essential tools for all these matter; for craftsmen will not be found everywhere and there are few men who cannot make something work for a day.¹³

We have only to look to the damage done to modern highway systems through its used by large, heavily laden super-trucks to realize that a similar occurrence could happen 1600 years ago if heavy laden wagons consistently traveled the road. Not only would these wagons cause deterioration to the road surface but also would slow down imperial couriers and the movement of armies and their supplies. These load limits were imposed for the sake of efficiency not because they represented a physical impossibility. J. Spruytte is his 1977 experiment already demonstrated that using the dorsal yoke, loads heavier than 1,500 Roman pounds could be hauled¹⁴.

As western Europe moved through the Dark Ages into the Middle Ages these networks of roads deteriorated, especially in the remnants of the Western Roman Empire. With the fall of the central government in Rome, there ceased to be a body to maintain and repair those roads. Nevertheless there were efforts to repair some of the Roman roads. As early as the Carolingian period the government undertook repairs of the Roman Roads and rebuilding of bridges¹⁵.

New roads sprang up and in many areas. Medieval commerce, for the most part, was forced to move over either muddy tracks or cart paths. Medieval roads were so poor that the people when out of their way to use the old Roman roads¹⁶. As the population of Western Europe dispersed to new areas some Roman roads were abandoned as they no longer went where people wanted to go and new roads were developed¹⁷. During the building of the great cathedral at Troyes, the stone hauled from the Tonnerre quarries to the building sites traveled over the original Roman roads¹⁸ indicating that the old Roman roads remained in use during the Middle Ages, and even into the Renaissance. "Medieval roads would always remain inferior to their Roman predecessors, except possibly in cities and towns.."¹⁹

Chevallier, p. 131
Ibid., p. 203
Abeele, Spruytte. passim.
Chevallier, pp. 93-106
Ibid., pp. 42-45
Th. Code, 8.5.8
Lefebvre des Noëttes, 1924, p. 86
White, p. 60
veredarii, official couriers, esp. imperial couriers
Th. Code 8.5.17
Th. Code 8.5.30
Polge, 34-35
Xenophon, Cyropaedia, 6.2.33-34
Spruytte, pp. 98-99
Fossier, p. 522
Langdon, p. 117
Leighton, p. 52
Piétresson de Saint-Aubin, p. 594
Landgon, p. 118