History of road transport

The history of road transport started with the development of tracks by humans and their beasts of burden.

Early roads

The first forms of road transport were horses, oxen or even humans carrying goods over tracks that often followed game trails, such as the Natchez Trace. [Lay (1992), p5] In the Stone Age humans did not need constructed tracks in open country. The first improved trails would have been at fords, mountain passes and through swamps. [Lay (1992), p7] The first improvements would have consisted largely of clearing trees and big stones from the path. As commerce increased, the tracks were often flattened or widened to accommodate human and animal traffic. Some of these dirt tracks were developed into fairly extensive networks, allowing communications, trade and governance over wide areas. The Incan Empire in South America and the Iroquois Confederation in North America, neither of which had the wheel, are examples of effective use of such paths.

The first goods transport was on human backs and heads, but the use of pack animals, including donkeys and horses, developed during the Stone Age. The first vehicle is believed to have have been the travois, a frame used to drag loads, which probably developed in Eurasia after the first use of bullocks (castrated cattle) for pulling ploughs. In about 5000 BC, sleds developed, which are more difficult to build than travois, but are easier to propel over smooth surfaces. Pack animals, ridden horses and bullocks dragging travois or sleds require wider paths and higher clearances than people on foot and improved tracks were required. [Lay (1992), p25] As a result by about 5000 BC roads developed along the tops of ridge in England, including the Ridgeway, to avoid crossing rivers and bogging. [Lay (1992), p9]

Harappan roads

Street paving has been found from the first human settlements around 4000 BC in cities of the Indus Valley Civilization on the Indian subcontinent, such as Harrapa and Mohenjo-daro.

Wheeled transport

Wheels appear to have been developed in ancient Sumer in Mesopotamia around 5000 BC, perhaps originally for the making of pottery. Their original transport use may have been as attachments to travois or sleds to reduce resistance. It has been argued that logs were used as rollers under sleds prior to the development of wheels, but there is no archeological evidence for this. [Lay (1992), p27] Most early wheels appear to have been attached to fixed axles, which would have required regular lubrication by animal fats or vegetable oils or separation by leather to be effective. [Lay (1992), p28] The first simple two-wheel carts, apparently developed from travois, appear to have been used in Mesopotamia and northern Iran in about 3000 BC and two-wheel chariots appeared in about 2800 BC. They were hauled by onagers, related to donkeys. [Lay (1992), p28]

Heavy four-wheeled wagons developed about 2500 BC, which were only suitable for oxen-haulage, and therefore were only used where crops were cultivated, particularly Mesopotamia. [Lay (1992), p28] Two-wheeled chariots with spoked wheels appear to have been developed around 2000 BC by the Andronovo culture in southern Siberia and Central Asia. At much the same time the first primitive harness enabling horse-haulage was invented. [Lay (1992), p28]

Wheeled-transport created the need for better roads. Generally natural materials cannot be both soft enough to form well-graded surfaces and strong enough to bear wheeled vehicles, especially when wet, and stay intact. In urban areas it began to be worthwhile to build stone-paved streets and, in fact, the first paved streets appear to have been built in Ur in 4000 BC. Corduroy roads were built in Glastonbury, England in 3300 BC [Lay (1992), p51] and brick-paved roads were built in the Indus Valley Civilization on the Indian subcontinent from around the same time. Improvements in metallurgy meant that by 2000 BC stone-cutting tools were generally available in the Middle East and Greece allowing local streets to be paved. [Lay (1992), p43] Notably, in about 2000 BC, the Minoans built a 50 km paved road from Knossos in north Crete through the mountains to Gortyn and Lebena, a port on the south coast of the island, which had side drains, a 200 mm thick pavement of sandstone blocks bound with clay-gypsum mortar, covered by a layer of basaltic flagstones and had separate shoulders. This road could be considered superior to any Roman road. [Lay (1992), p44]

Royal Road

In 500 BC, Darius I the Great started an extensive road system for Persia (Iran), including the famous Royal Road which was one of the finest highways of its time. The road was used even after the Roman times. Because of the road's superior quality, mail couriers could travel 2,699 km in seven days.

Roman roads

With the advent of the Roman Empire, there was a need for armies to be able to travel quickly from one area to another, and the roads that existed were often muddy, which greatly delayed the movement of large masses of troops. To resolve this issue, the Romans built great roads. The Roman roads used deep roadbeds of crushed stone as an underlying layer to ensure that they kept dry, as the water would flow out from the crushed stone, instead of becoming mud in clay soils. The legions made good time on these roads and some are still used millennia later.

On the more heavily traveled routes, there were additional layers that included six sided capstones, or pavers, that reduced the dust and reduced the drag from wheels. The pavers allowed the Roman chariots to travel very quickly, ensuring good communication with the Roman provinces. Farm roads were often paved first on the way into town, to keep produce clean. Early forms of springs and shocks to reduce the bumps were incorporated in horse drawn transport, as the original pavers were sometimes not perfectly aligned.

Roman roads deteriorated in medieval Europe because of lack of resources and skills to maintain them, but many continued to be used, and some are still partially used today, for instance, parts of England's A1.

Early tar-paved roads

In the medieval Islamic world, many roads were built throughout the Arab Empire. The most sophisticated roads were those of the Baghdad, Iraq, which were paved with tar in the 8th century. Tar was derived from petroleum, accessed from oil fields in the region, through the chemical process of destructive distillation.cite book|author=Dr. Kasem Ajram|title=The Miracle of Islam Science|edition=2nd Edition|publisher=Knowledge House Publishers|year=1992|id=ISBN 0-911119-43-4]

New construction methods in the 18th and 19th centuries

As states developed and became richer, especially with the Renaissance, new roads and bridges began to be built, often based on Roman designs. Although there were attempts to rediscover Roman methods, there was little useful innovation in road building before the 18th century.

Between 1725 and 1737 General George Wade constructed convert|250|mi|km of road and 40 bridges to improve Britain's control of the Scottish Highlands, using Roman road designs with large stones at the bottom and gravel on top, with a typical overall depth of two metres. They were so poorly aligned and steep, according to Thomas Telford, "as to be unfit for the purposes of civil life" and also rough and poorly drained. [Lay (1992), p72]

Toll roads

England and Wales

As traffic levels increased in England and roads deteriorated. Toll roads were built by "Turnpike Trusts", especially between 1730-1770. It has been claimed that as a result the time taken between London, to York, Manchester or Exeter was cut by two-thirds between 1720 and 1780. [cite web
last =Huxford
first =Robert
title =How old is that route?
publisher =Institution of Civil Engineers
date = 3 September 2003
url =http://www.ice.org.uk/downloads//BS-History_of_Routes.pdf
format =pdf
accessdate = 2007-01-19 ] Blind Jack Metcalf (1717-1810) built about 300 km (180 miles) of turnpike road between 1753 and 1810, mainly in Lancashire, Derbyshire, Cheshire and Yorkshire. He understood the importance of good drainage and surfaced his roads with "a compact layer of small, broken stones with sharp edges", rather than the naturally rounded stones traditionally used in European road building. British turnpike builders began to realise the importance of selecting clean stones for surfacing, and excluding vegetable material and clay to make better lasting roads. [Lay (1992), p72]

United States of America

Turnpikes were also later built in the United States. They were usually built by private companies under a government franchise. They typically paralleled or replaced routes already with some volume of commerce, hoping the improved road would divert enough traffic to make the enterprise profitable. Plank roads were particularly attractive as they greatly reduced rolling resistance and mitigated the problem of getting mired in mud. Another improvement, better grading to lessen the steepness of the worst stretches, allowed draft animals to haul heavier loads.

Water transport on rivers and canals carried many farm goods from the frontier U.S. (between the Appalachian mountains and Mississippi River) in the early 19th century, but the shorter route over the mountains had advantages. Successful farms created a demand for imported and manufactured goods from the Atlantic coast. The commercial interests of the East were quick to see the possibilities of this new market. An eager rivalry sprung up between the merchants of New York, Philadelphia, and Baltimore. Everywhere ways and means of cheaper transportation were discussed. In this subject the western farmer was vitally interested, for freight charges added nearly one third to the cost of merchandise transported over the mountains. The cotton planter of the Seaboard States, also, feeling the competition of the Southwest, where riverways were abundant and easily navigable, saw the need of better roads to tidewater, in order to lessen the cost of marketing his produce. [Johnson (1915), p254-255]

The popular demand for better roads was not recent. All the states had encouraged, directly or indirectly, the building of turnpikes and bridges. Between 1793 and 1812, Pennsylvania had chartered fifty-five turnpike companies, and other states had been scarcely less ready to grant articles of incorporation to stock companies. Private enterprise had, indeed, done much to improve communication along the seaboard. Turnpikes and bridges had shortened the journey by stage from Boston to Washington to four and a quarter days by the year 1815. [Johnson (1915), p255]

The magnitude of the transportation problem was such, however, that neither individual states nor private corporations seemed able to meet the demands of an expanding internal trade. As early as 1807, Albert Gallatin had advocated the construction of a great system of internal waterways to connect East and West, at an estimated cost of $20,000,000. But the only contribution of the national government to internal improvements during the Jeffersonian era was an appropriation in 1806 of two percent of the net proceeds of the sales of public lands in Ohio for the construction of a national road, with the consent of the states through which it should pass. By 1818 the road was open to traffic from Cumberland, Maryland, to Wheeling, West Virginia. [Johnson (1915), p256]

In 1816, with the experiences of the war before him, no well-informed statesman could shut his eyes to the national aspects of the problem. Even President Madison invited the attention of Congress to the need of establishing "a comprehensive system of roads and canals". Soon after Congress met, it took under consideration a bill drafted by Calhoun which proposed an appropriation of $1,500,000 for internal improvements. Because this appropriation was to be met by the moneys paid by the National Bank to the government, the bill was commonly referred to as the "Bonus Bill". But on the day before he left office, President Madison vetoed the bill because it was unconstitutional. The policy of internal improvements by federal aid was thus wrecked on the constitutional scruples of the last of the Virginia dynasty. Having less regard for consistency, the House of Representatives recorded its conviction, by close votes, that Congress could appropriate money to construct roads and canals, but had not the power to construct them. As yet the only direct aid of the national government to internal improvements consisted of various appropriations, amounting to about $1,500,000 for the Cumberland Road. [Johnson (1915), p257-258]

As the country recovered from financial depression following the Panic of 1819, the question of internal improvements again forged to the front. In 1822, a bill to authorize the collection of tolls on the Cumberland Road had been vetoed by the President. In an elaborate essay Monroe set forth his views on the constitutional aspects of a policy of internal improvements. Congress might appropriate money, he admitted, but it might not undertake the actual construction of national works nor assume jurisdiction over them. For the moment the drift toward a larger participation of the national government in internal improvements was stayed. Two years later, Congress authorized the President to institute surveys for such roads and canals as he believed to be needed for commerce and military defense. No one pleaded more eloquently for a larger conception of the functions of the national government than Clay. He called the attention of his hearers to provisions made for coast surveys and lighthouses on the Atlantic seaboard and deplored the neglect of the interior of the country. Of the other presidential candidates, Jackson voted in the Senate for the general survey bill; and Adams left no doubt in the public mind that he did not reflect the narrow views of his section on this issue. Crawford felt the constitutional scruples which were everywhere being voiced in the South, and followed the old expedient of advocating a constitutional amendment to sanction national internal improvements. [Johnson (1915), p 309-310]

In President Adams' first message to Congress, he advocated not only the construction of roads and canals but also the establishment of observatories and a national university. President Jefferson had recommended many of these in 1806 for Congress to consider for creation of necessary amendments to the Constitution. Adams seemed oblivious to the limitations of the Constitution. In much alarm Jefferson suggested to Madison the desirability of having Virginia adopt a new set of resolutions, bottomed on those of 1798, and directed against the acts for internal improvements. In March, 1826, the general assembly declared that all the principles of the earlier resolutions applied "will full force against the powers assumed by Congress" in passing acts to protect manufacturers and to further internal improvements. That the Administration would meet with opposition in Congress was a foregone conclusion. [Johnson (1915), p319-320]

Trésaguet's work in France

In France, Pierre-Marie-Jérôme Trésaguet is widely credited with establishing the first scientific approach to road building about the year 1764. He wrote a memorandum on his method in 1775, which became general practice in France. It involved a layer of large rocks, covered by a layer of smaller gravel. The lower layer improved on Roman practice in that it was based on the understanding that the purpose of this layer (the sub-base or base course) is to transfer the weight of the road and its traffic to the ground, while protecting the ground from deformation by spreading the weight evenly. Therefore, the sub-base did not have to be a self-supporting structure. The upper running surface provided a smooth surface for vehicles, while protecting the large stones of the sub-base. Trésaguet understood the importance of drainage by providing deep side ditches, but he insisted on building his roads in trenches, so that they could be accessed from the sides, which undermined this principle. Well-maintained surfaces and drains protect the integrity of the sub-base and Trésaguet introduced a system of continuous maintenance, where a roadman was allocated a section of road to be kept up to a standard. [Lay (1992), p73-74]

Developments in England

Telford

Thomas Telford (1757-1834) also made substantial advances in the engineering of new roads and the construction of bridges. Under his supervision 1,500 km of roads and 1,000 bridges were built in Scotland between 1802 and 1822. He elaborated on the Trésaguet method by a more complex and costly system of stonework in the subgrade, but his main improvement over Trésaguet was the raising of his roads above the natural level to improve drainage or the drainage of the area around the road. [Lay (1992), p75]

McAdam

John Loudon McAdam (1756-1836) designed the first modern highways. He developed an inexpensive paving material of soil and stone aggregate (known as macadam), and he embanked roads a few feet higher than the surrounding terrain to cause water to drain away from the surface. He had noticed in his observations that coaches with narrow, iron-tyred wheels and moving at relatively high speed were causing significant damage to roads, but that areas of small broken stones were most resistant to damage, while the areas that had large surface stones degraded fastest. His solution was to create roads with three layers of stones laid on a crowned subgrade with side ditches for drainage. The first two layers consisted of angular hand-broken aggregate, maximum size 3 inches (75 mm), to a total depth of about 8 inches (200 mm). The third layer was about 2 inches (50 mm) thick with a maximum aggregate size of 1 inch (25 mm). Each layer would be compacted with a heavy roller, causing the angular stones to lock together with their neighbours. It is possible that his initial decision not to use the heavy layer of base stones used by Telford in his subgrade reflected lack of suitable stones, but McAdam quickly saw they were not necessary. In practice, his roads proved to be twice as strong as Telford's roads. [Lay (1992), p77] He also insisted on raising the roads to ensure good drainage and flat crowned surfaces, rather than ridges built into the road to encourage drainage. [Lay (1992), p78]

McAdam was adamantly opposed to the filling of the voids between his small cut stones with smaller material, possibly as a reaction against the use of poor materials, including soil and vegetable matter, on roads in the past. Nevertheless, in practice road builders began to introduce filler materials such as smaller stones, sand and clay, and it was observed that these roads were stronger as a result. Macadam roads were being built widely in the United States and Australia in the 1820s and in Europe in the 1830s and 1840s. [Lay (1992), p83]

Development of modern paved roads

Various systems had been developed over centuries to reduce washways, bogging and dust in cities, including cobblestones and wooden paving. Tar-bound macadam (tarmac) was applied to macadam roads towards the end of the 19th century in cities such as Paris. In the early 20th century tarmac and concrete paving were extended into the countryside.

Incidentally, bicyclists were among the early campaigners on what was called the Good Roads Movement. Bicycling was an extremely popular recreation among the middle and upper classes in the late 19th century and was more fun on paved roads.

References

* cite book
last =Johnson
first =Allen
authorlink =Allen Johnson (teacher)
title =Union and Democracy
publisher =Houghton Mifflin Company
date =1915
location =Cambridge, Massachusetts
* cite book
last =Lay
first =M G
authorlink =
title = Ways of the World
publisher =Primavera Press
date =1992
location =Sydney
pages =401
id = ISBN 1-875368-05-1

Notes

See also

* Caravanserai
* Dromography
* Trade route
* Horses in the Middle Ages

External links

* [http://curbstone.com/_macadam.htm Macadam - Road Building in America]
* [http://www.vehiclerecovery.org/history/index.htm UK Vehicle Recovery History]