When the Romans began their conquest of Celtic Britain in 43AD, they found a haphazard collection of roads and paths, most connecting local fields and hamlets, but also some longer distance trade routes (e.g.. along the North Downs in Kent, and the Icknield Way along the Chiltern’s into Norfolk).
The Roman administration, however, needed a better network of roads to connect its new towns and army posts and to speed the flow of both trade goods and troops. In building their network of roads the Romans mostly ignored the Celtic paths, partly because the Roman towns and forts were built on new sites away from the Celtic settlements.
By 82AD the Romans had pushed north as far as a line between the Clyde and the Firth of Forth. During this campaign alone the army built over 60 forts and over 1200 miles of roads. The imperial posting service, used by Roman officials, maintained inns and relays of horses at intervals of 30 to 50 kilometres along the roads.
The minor roads (sometimes called “economic roads”) were also built by the Roman army to link economic centres, such as the Mendip lead mines and the Nene potteries, with administrative capitals like Silchester, and the coastal ports.
At a best guess there were between 8000-10,000 miles of roads constructed during the first hundred years of Roman occupation. There was a third level of roads at the local level, connecting villas, temples, farms, and villages to larger roads and market towns.
The full extent of this road building is clear when you consider that according estimates by historians, no village or farm was more than 7 miles from a purpose-built road! The most vital priority was the movement of troops and supplies from the channel ports of Richborough, Dover, and Lympne to the military centres at London, Colchester, and the front-line legionary forts.
The first frontier was set up along a road extending from Exeter to Lincoln, running through Bath, Gloucester, and Leicester. This was known as the Fosse Way, the first great Roman road in Britain. The Fosse Way has been largely adapted by modern highways.
The next military push established a new frontier between Lincoln and York, Wroxeter and Chester, and Gloucester and Caerleon. After these “front-line” roads had been established. The Romans turned their attention to expanding the network of minor roads within their new possessions, to better aid the flow of trade.
It is a fallacy to think that Roman roads are always straight. The Roman engineers were no fools – if there was a natural obstacle in the way, the road naturally deviated to go around it. The Romans had yet to invent front axle steering, so sharp corners where avoided.
That said, for the most part Roman roads were laid out in straight lines between sighting landmarks. Small hills were cut through, and wet ground covered by causeways, or timber embankments. So, how did the Romans build these famous roads of theirs?
The roads were literally highways, raised up on a cambered bank of material dug from roadside ditches. In general there were 3 layers. The first layer of large stones was covered by a second layer of smaller stones, then a top layer of gravel or small stones. Each layer varied in depth from 2-12 inches. The choice of material depended upon what was locally available; in the chalk areas like the Wessex Downs a mix of chalk, flint, and gravel was used. The paved area was edged with upright stones to give stability, and the major roads had ditches to each side, about 84 feet apart.
After the fall of the Roman Empire the road system fell into a state of disrepair and by the end of the Middle Ages, there was in effect no road system in the country. The only routes available were unpaved tracks, muddy and impassable in winter and dusty and impassable in summer. Diversions around particularly poor stretches resulted in sinuous alignments. The state of the roads combined with the general lawlessness at the time meant only the determined or insane travelled them.
Roads in Roman Britain, Hugh Davies, The History Press Ltd (14 Mar 2008
Roman Roads (Shire archaeology series), Richard W Bagshawe, Shire Publications Ltd (26 April 1979)
The Roads of the Romans (Getty Trust Publications: J. Paul Getty Museum), Romolo Augusto Staccioli, J. Paul Getty Museum; illustrated edition edition (1 Oct 2003)