History of road transport
Roman roads fell into disuse and wheeled vehicles more or less disappeared throughout Europe until they began to make a slow comeback nearly a thousand years later during the Middle Ages. Movement of goods and people was then largely on foot or by pack animal and tracks were sufficient. Bridges, usually the responsibility of the religious orders, were the main priority as water crossings were often hazardous.
Trade between cities was on the increase and movement by coastal shipping was too slow and unreliable.Something had to be done about roads and it was not long before the first comprehensive if ineffectual legislation on maintenance was drafted. Large waggons such as is shown above, of maybe two to four tons capacity and drawn by as many as six horses or oxen began to appear on the scene towards the end of the sixteenth century. Public coaches began to appear also. They were slow, covering not much more than twenty km in a day, and amazingly uncomfortable, being totally without springs or even spoked wheels. In any case people generally travelled little if at all and rarely for pleasure due to the terrible roads, particularly bad in winter.
The spread of private toll roads in the UK and the construction of the state-managed network in France, together with an expanding postal service went hand-in-hand with a rapid growth in road transport during the eighteenth century. By the end of it, in the UK at least, nearly all major cities were within a days' journey from London by stagecoach (so called because they changed horses every hour or so at stages, which were also inns). These could average 15 km an hour carrying about twelve passengers, but were, of course, very expensive. Travel by coach was not for everybody. A long days' journey of 300km, to say, Leeds, would have cost well over a weeks' wages for a skilled worker, in tolls, transport and innumerable tips to notoriously rapacious coach drivers and staff at the inns. The equivalent in price today would be a return trans-Atlantic ticket.
Early in the nineteenth century, the converging technologies of road construction and light high pressure steam engines stimulated the introduction of motorised road vehicles. In the UK and to a far lesser extent, France, a number of interurban and local services started up during the 1830's. Some operated reliable scheduled services carrying up to eighteen passengers at average speeds of up to 25km per hour.

Gurney 12 bhp steam coach: top speed of 16kph; ran four trips per day between Gloucester and Cheltenham (13km) for four months in 1831
However, at least in the UK, powerful forces were conspiring against them. The politically powerful landowners had invested heavily in rail transport and stood to lose too much from competition. They effectively suppressed motorised road transport for sixty years through legislation imposing a speed limit of 5km and cleverly made it self-policing by requiring that a vehicle be preceded by a man on foot with a red flag.
In any case rail proved itself to be probably the right choice at the time for cheap mass transport. Roads would not have stood up to heavy motorised traffic, given the weak maintenance management structures of the time. Although rail infrastructure was more expensive to build than roads because of the moderate grades and sweeping curves that the relatively low-powered and inefficient locomotives demanded, when allied to low-friction steel rails it ensured low unit operating costs. Rail fares plummeted in the space of a few years and mass travel became possible with the coming of the third class ticket. Leeds was now not much over a day's wages from London. By the 1860's, most British cities were linked to London at average speeds of up to 80kph. It didn't really get much better than that for the next hundred years.
The high-speed internal combustion engine, with a far superior power to weight ratio, appeared in the 1860's. Relying on gas it was still very cumbersome until with liquid fuel it literally exploded on the scene in the 1880's as a highly mobile form of motive power. Vehicle technology rushed to meet it and by the turn of the century motorised road transport was, if not yet commonplace, under intense development.By the first world war it dominated local transport of goods and people. By the second it had overtaken rail for long distance travel and subsequently took over goods transport.
As car prices dropped, bottoming in the UK at 100GBP in the thirties, private ownership percolated rapidly through descending income levels, becoming general in the 60's. The motorcar has now rivalled the weather as a source of conversation for almost a hundred years. It will continue to fill conversational gaps, but as its popularity wanes and its banality increases (as has, to be fair, its reliabilty), it will perhaps generate no more than the polite interest we would now accord to vacuum cleaners.
more (bicycles mainly)

