Roman Construction Methods - The Road
Created | Updated Apr 30, 2010
The Romans probably discovered how to build roads from their pre-Roman ancestors, a tribe called Etrusci or Tusci from Northern Italy, commonly referred to as the Etruscans. The Romans for many reasons became excellent road builders. Roman building methods were adapted and improved as time went on and as skills improved.
There were laws governing the construction of roads dating from 450 BC, stating the width should be 2.5 meters, and stating the rights of passage on the Empires roads. The 9,000 miles of roads in Britain represented a fraction of the total of over 55,600 miles throughout the Empire stretching as far to the east as the Silk Road to China. As an example of how the roads improved communication, it was possible for the official mail to travel 500 miles a day using this system. Overnight accommodation for travellers was placed at 15 mile intervals along the main routes,
During the invasion roads were vital to the success of the conquest of Britain. As the legions pushed north disregarding the old track ways, they laid roads called Via munire (tribute roads) to link the forts they established. Many of the early settlements were built near these forts, later new towns developed near the major roads.
The next type of road to develop was a network of minor trade roads called viae rusticae (described in surviving documents as rural or boorish/peasant roads) built to serve local trade and manufacturing centres. Last was the network of local paths and service roads some un surfaced known as viae terrenae
linking local buildings such as shrines, houses and estates to the network.
Marcus Vitruvius Pollio
Vitruvius (Marcus Vitruvius Pollio, 75 BC, to 15 BC) was a military engineer, architect and builder. What makes him important is that he wrote the De architectura, 1, the only Roman work on Roman architecture of the time that is known to have survived. Dedicated to the emperor Caesar Augustus, it is now known as The Ten Books and describes many Roman and Greek building methods.
The Roman Road system allowed the rapid spread of Christianity the apostles and many Christians travelled across the Empire easily, Roman troops even providing some protection on the way.
Building Roman Roads
The first thing to remember about Roman roads is that they were built wherever the military surveyors wanted. There were no planning restrictions and any objections of the local population was at the bottom of the list, this is one reason why they are so straight. The other reason was the Roman method of surveying useing the tool known as a groma, the route was surveyed in sections marking out the high points. Then, after the first stage had been completed, the route was surveyed again between the high points to make it as straight as possible. The road did not have to go round anything apart from natural obstacles. Initially the Romans built roads mainly for military transport, to allow the rapid movement of troops and to transport the supplies to sustain them.
When things quietened down, the civilian use of the road began with settlers, who followed the army into newly pacified areas. The areas near the military bases often formed the first settlements.
After the settlers came the traders and farmers, using the roads to move goods and produce. These could be moved quickly and safely and breakages were fewer and food could travel further and arrive in a fresh condition. Consumption of luxury goods and items from other parts of the Empire also went up as a result of the good road access.
The road system was so effective that as the empire came to an end invading armies travelled along them to attack the heart of the empire. In the final years of Roman occupation of Britain some roads were blocked to hinder raiders. When the empire collapsed the road network fell into decline and practically disappeared. The communication system provided by the Roman road network was not rivalled until the 19th century when the railway system spread throughout Europe.
The Stages Of Building A Roman Road
There were five main stages to the building of a standard Roman road:
Stage 1-
Surveying the route. Teams were sent out to plan the route of the proposed road and place markers for the building teams. This was mainly the job of the military engineers who used the groma to survey the route and plan the route of the road. It appears that plans were made of the proposed route connecting the surveyed points. This enabled the builders to adjust the route to avoid natural obstacles or to use established river crossings. The road was then staked out by the surveying team.
Stage 2-
Clearing the route. This was a two part process, first the route was cleared of all obstacles, trees in the path of the road were felled and any rocks or stone removed to be reused in the roads construction.
The second part involved the digging of the foundation trench. The average dimensions were one meter deep and 2.5 meters wide. A heavy plough was often used to break up the ground surface to make the digging easier.
Stage 3-
Lining the bottom of the foundation trench with a layer of large stones, topping this with a layer of rubble, and then ramming it all down to form a solid foundation and prevent subsidence.
Stage 4-
The foundation layer was then covered with a layer of smaller coarse stones, thease were easier to level, and compact firmly. The final foundation layer was a layer of sand or a mixture of cement2 sand and gravel, it was on this surface the road surface was laid.
Stage 5 -
Laying kerb stones at the outer edges and then surfacing the remaining inner surface. A variety of surfacing materials were used, closly fitted stone slabs or heavy gravel being the most common. A stone surface was often given an additional surface of compacted gravel. All roads were given a cambered3 surface to shed rain water and aid drainage.
The final makeup of the road was determined by three factors:
its intended use, the materials available locally and the terrain it was crossing.
The method for Roads on soft or wet terrain
The terrain was an important factor on soft or boggy ground there could be no ditch as in stage 2, the road was supported on timber foundations: large baulks of timber were laid on the ground surface, and fixed into the ground. On top of these there were laid lengths of timber in pairs parallel to the direction of the road giving the appearance of railway sleepers and rails.
The second stage of this process was either to pack the spaces between the timber rails with brushwood or, on even wetter ground, to lay timber across the timber rails. In the case of the brushwood packing, it was laid down in bundles in two layers laid in opposite directions to each other.
Roads on Wetter ground
On this type of ground surface much more timber was used, this was used to form a continuous surface on which stone slabs or similar materials could be then laid, as in stage 5. In some cases the stone dressing was omitted and a simple wooden road was laid.
The final surface layer was of coarse small stones that were levelled and compacted firmly. This layer was often topped with sand or a mixture of sand and gravel.
The surface layer was then laid; this layer was also compacted firmly. This layer was often topped with sand or consisted entirely of a mixture of sand and gravel.
After the finishing of the road surface there were two final things to do, construct an agger, or embangment, on each side of the road, and then dig a drainage ditch on each side. The agger was built from the spoil from the road's foundation trench and from the drainage ditches dug each side of the agger. This lifted the road slightly above the level of the surrounding countryside, this cleared area also made it difficult to set an ambush for troops or travellers as the cleared area improved the view of the road ahead and travellers could see any potential dangers.
Milestones
The Milliarium Aureum4 was the milestone that was placed in Rome, on the orders of Augustus, as the starting point from which all mileages to other parts of the empire were to be measured. Milestones on Roman roads gave the distance to Rome as well as local information, and were placed 1000 paces apart5. All roads were provided with milestones, they showed the distance to each town on that section of the road served. Often the milestone gave the date of the roads construction and the name of the Emperor.
"All roads lead to Rome" ...and, evidently, away from it.Upkeep And Maintainance
Initially, the cost of the road was borne by the state; after that it was the responsibility of the local government to raise the money to keep the road in good repair. An official called the Curatores Viarum was appointed who had to raise the money to maintain the roads in his care. Improvements and maintenance work would be carried out by slaves or other forced labour and prisoners.
Roman roads were not free. There were tolls collected at the towns along the course of the road. As a point of interest, the bridges were a particular source of revenue. This explains the survival and continuous use of fords along the routes.
The best Roman road to visit today can be found in Sutton Park in Birmingham, the visitor can walk it in safety as it has not used since the Romans left Britain.
Roman Road Map
The Austrian National Library is home to a parchment scroll The Tabula Peutingeriana, created in the Middle Ages. This is a copy of a road map from the late Roman Empire. The seven metre parchment shows a network of Roman roads from Spain to India. The scroll is listed on Unesco's Memory of the World Register.
Some Of The Major Roman Roads In Britain
These are not the only roads built in Britain but are the best known, known today by their names that date back only as far as the Saxon kingdoms, who gave them the names we use today6 The Romans named the road after the Censura or Censor7 who was responsible for its construction, or simply by where it went. Some of the roads better known roads in Britain are listed here in approximate order of length:
Watling Street, the most important Roman road which runs East to West across Great Britain from Dover (Portus Dubris) to Brecon (Gaer, Y Gaer).
The north–south road running up the eastern side of Great Britain. Starting in London (Londinium), it proceeds north and after the River Nene crossing, the road heads north into Lincoln (Lindum). This supported the Fosse Way providing access to the north.
An important north–south road running up the western side of Great Britain. The road runs from Exeter (Devon) in the South to Lincoln (Lincolnshire) in the North, forming one of the main routes in Roman Britain.
Stane Street connected the ports of the south east to London and Lincoln useing Ermine Street and connecting the east coast ports travelling on the Fen Causeway and the Peddars Way crossing the Wash via the Kempstone Holme next the Sea ferry.
Connecting the defensive elements of the west coast from the port of Ravenglass (Glannoventa) to the eastern end of Hadrian's Wall at Bowness (Maia).
An east west road connecting the Stanegate Fort Carlisle (Luguvalium) to the Stanegate Fort Corbridge (Corstopitum). This road and its forts formed the original northern frontier, until the building of Hadrian's Wall. This road is still known locally as the Military Road.
This road is an extention of Watling Street from Brecon (Gaer, Y Gaer) to Caerleon (Iscia Silurum) connecting Watling Street with the port on the Severn estury.
Other Noteable Roads
Dere Street
A north south road connecting York (Eboracum) to Chew Green at the eastern end of the Antonine wall.
Akeman Street
London (Londinium) to Cirencester (Corinium Dobunnorum).
