National road systems have been either centrally planned or simply allowed to grow piecemeal according to local initiatives.The motive underlying central planning was generally military, to ensure that large numbers of troops could be moved rapidly to restore order or repress dissent, depending on the point of view. This underlay the Roman road system, which was unique in that it was not country- but empire-wide. It also motivated the French system, developed in the late 17th and early 18th centuries, the German (1930’s) and the more recent American Interstate system (1950’s). The British never bothered, perhaps to their credit, although one must except the building of military roads in Scotland for largely repressive purposes after the failed revolution of 1745, They relied on a rather happy-go-lucky management approach relying on local responsibility and private enterprise, guided, very approximately, by largely ineffectual national legislation.
The Romans took their roads very seriously. Although there have been roads of sorts since the invention of the wheel they were the first to plan and construct a sustainable network, intended to link Rome to the major cities of Italy and thence to the outposts of Empire. Eighty thousand km were built over five hundred years of which twenty thousand km in Gaul alone. Construction norms were not those of the modern road, which aims at a twenty-year useful life. They built for centuries and many sections are still there today. However, most of their roads were not build to the high standards of such roads as the Via Appia. There was, in fact, a hierarchy of roads as there is today in every country. It comprised two types of main road, whose width could be either 13m or 7m, and two levels of secondary road, varying between three and four metres wide. Roman networks provided many of the services we take for granted now. Travellers could buy road maps and even guides to the many hotels and restaurants on the way. Like today the food was often reputed to be execrable, as was the accommodation, and wealthier travellers were advised to bring their own. Officials on government business were well provided for, with their own network.
Their system began to fall into disrepair and essentially oblivion after the fifth century, although parts of it continued in use throughout the Middle Ages. Some provided a foundation for subsequent works. However, the system was not really adapted to later needs for mobility, where were mainly for local movements. In addition, Roman roads, like the motorways and railways of 2000 years later, tended take the shortest distance from one major town to another, ignoring topography and the population in between. Their roads ran in straight lines, over natural obstacles and with sweeping curves to accommodate long wheelbase carts. The builders tolerated very steep slopes, up to 20% in some cases. The meandering British roads did so for very good reasons, although future generations of drivers rarely appreciated them.
The French system, whether or not its raison d’être was entirely benevolent, being designed mainly for the rapid movement of troops in case of war or insurrection, was hundreds of years ahead of the British one. Centred on Paris, many thousands of kilometres were constructed throughout the 18th century, linking it to most of the major cities. Much of its design and construction was directed by Tressaguet, using a method that was, like that of Telford in the UK, robust but expensive. Preventive maintenance was rightly considered to be essential. Unfortunately, it relied on forced labour (the infamous corvée, afterwards applied throughout the French and many other colonies until the 1930’s). Everyone between 16 and 60 living within three leagues of the road had to provide their labour, materials and means of transport (when they had any). It was highly unpopular, seen rightly as a form of inverse welfare where the poor are called upon to support the rich (plus ça change), and was superseded in 1776 by a cash contribution, too late to prevent the revolution.
From an institutional standpoint, the French were also far ahead of the British. The Service de voirie was put in place in 1716 to manage road works and the Ecole de ponts et chausées to provide formal training for future engineers in 1747. In the UK, civil engineers were essentially trained during a long apprenticeship on the job until the first courses in civil engineering were set up in 1838. In 1841 Trinity College, Dublin founded its Engineering School (where my maternal great-grandfather graduated in 1863 and myself ninety-nine years later).