The history of steam road vehicles comprises the development of vehicles powered by a steam engine for use on land and independent of rails, whether for conventional road use, such as the steam car and steam waggon, or for agricultural or heavy haulage work, such as the traction engine.
The first experimental vehicles were built in the 18th and 19th century, but it was not until after Richard Trevithick had developed the use of high-pressure steam, around 1800, that mobile steam engines became a practical proposition. The first half of the 19th century saw great progress in steam vehicle design, and by the 1850s it was viable to produce them on a commercial basis. This progress was dampened by legislation which limited or prohibited the use of steam-powered vehicles on roads. Nevertheless, the 1880s to the 1920s saw continuing improvements in vehicle technology and manufacturing techniques, and steam road vehicles were developed for many applications. In the 20th century, the rapid development of internal combustion engine technology led to the demise of the steam engine as a source of propulsion of vehicles on a commercial basis, with relatively few remaining in use beyond the Second World War.
Many of these vehicles were acquired by enthusiasts for preservation, and numerous examples are still in existence. In the 1960s, the air pollution problems in California gave rise to a brief period of interest in developing and studying steam-powered vehicles as a possible means of reducing the pollution. Apart from interest by steam enthusiasts, occasional replica vehicles, and experimental technology, no steam vehicles are in production at present.
Early steam-powered vehicles, which were uncommon but not rare, have considerable disadvantages as seen from a 21st-century viewpoint. They were slow to start, as water had to be boiled to generate the steam. They used a dirty fuel (coal) and put out dirty smoke. Fuel was bulky and had to be shoveled onto the vehicle and then into the firebox. Like a furnace, hot ash had to be removed and disposed of. The engine needed to be replenished with water in addition to fuel. Most vehicles had metal wheels and less than excellent traction. They were heavy. In most cases the user had to do their own maintenance. Top speed was low, about per hour, and acceleration was poor.
Steam vehicle technology evolved over time. Later steam vehicles used cleaner liquid fuel (kerosene), were fitted with rubber tyres and condensers to recover water, and were lighter overall. These improvements were not enough to keep pace with internal-combustion engines, however, which ultimately out-competed steam and remained dominant for the rest of the 20th century.
Early pioneers.
Early research on the steam engine before 1700 was closely linked to the quest for self-propelled vehicles and ships, the first practical applications from 1712 were stationary plant working at very low pressure which entailed engines of very large dimensions. The size reduction necessary for road transport meant an increase in steam pressure with all the attendant dangers, due to the inadequate boiler technology of the period. A strong opponent of high pressure steam was James Watt who along with Matthew Boulton did all he could to dissuade William Murdoch from developing and patenting his steam carriage built and operated in model form in 1784. In 1791 he built a larger steam carriage which he had to abandon to do other work.
During the latter part of the 18th century, there were numerous attempts to produce self-propelled steerable vehicles. Many remained in the form of models. Progress was dogged by many problems inherent to road vehicles in general, such as adequate road surfaces, suitable power plant giving steady rotative motion, tyres, vibration resistant bodywork, braking, suspension and steering among other issues. The extreme complexity of these issues can be said to have hampered progress over more than a hundred years, as much as hostile legislation.
Verbiest steam carriage.
Ferdinand Verbiest is suggested to have built what may have been the first steam carriage in about 1679, but very little concrete information on this is known to exist. It was not designed to carry a driver or goods as it was a small scale vehicle. It also seems that the Belgian vehicle served as an inspiration for the Italian Grimaldi (early 1700) and the French Nolet (1748) steam carriage successor.
Cugnot ""Fardier à vapeur".
Nicolas-Joseph Cugnot's "machine à feu pour le transport de wagons et surtout de l'artillerie"" ("fire engine for transporting wagons and especially artillery") was built in two versions, one in 1769 and one in 1771 for use by the French Army. This was the first steam wagon that was not a toy, and that was known to exist. Cugnot's "fardier" a term usually applied to a massive two wheeled cart for exceptionally heavy loads, was intended to be capable of transporting 4 tonnes (3.9 tons), and of travelling at up to . The vehicle was of tricycle layout, with two rear wheels and a steerable front wheel controlled by a tiller. There is considerable evidence, from the period, that this vehicle actually ran, making it probably the first to do so, however it remained a short lived experiment due to inherent instability and the vehicle's failure to meet the Army's specified performance level.
Symington steam carriage.
In 1786 William Symington built a steam carriage.
Fourness and Ashworth steam car.
A British patent No.1674 of December 1788 was granted for a steam car by Fourness and Ashworth.
Trevithick steam carriage.
In 1801 Richard Trevithick constructed an experimental steam-driven vehicle ("Puffing Devil") which was equipped with a firebox enclosed within the boiler, with one vertical cylinder, the motion of the single piston being transmitted directly to the driving wheels by means of connecting rods. It was reported as weighing 1520 kg fully loaded, with a speed of on the flat. During its first trip it was left unattended and was "self destructed". Trevithick soon built the "London Steam Carriage" that ran successfully in London in 1803, but the venture failed to attract interest and soon folded up.
In the context of Trevithick's vehicle, an English writer by the name of "Mickleham" in 1822 coined the term "Steam engine":
"It exhibits in construction the most beautiful simplicity of parts, the most sagacious selection of appropriate forms, the most convenient and effective arrangement and connexion uniting strength with elegance, the necessary solidity with the greatest portability, possessing unlimited power with a wonderful pliancy to accommodate it to the varying resistance: it may indeed be called "The steam engine"."
Evans steam-powered amphibious craft.
In 1805 Oliver Evans built the "Oruktor amphibolos" (literally "Amphibious digger"), a steam-powered, flat bottomed dredger that he modified to be self-propelled on both water and land. It is widely believed to be the first amphibious vehicle, and the first steam-powered road vehicle to run in the United States. However, no designs for the machine survive, and the only accounts of its achievements come from Evans himself. Later analysis of Evans's descriptions suggests that the engine was unlikely to have been powerful enough to move the vehicle either on land or water, and that the chosen route for its demonstration would have had the benefit of gravity, river currents and tides to assist with the vehicles' progress. The dredger was not a success, and after a few years lying idle, was dismantled for parts.
Summers and Ogle steam carriage.
In around 1830 or 1831 Summers and Ogle based at the Iron Foundry, Millbrook, Southampton, made two three-wheeled steam carriages.
In 1831 the firm's Nathaniel Ogle gave evidence on the steam carriage to the "Select Committee of the House of Commons on Steam Carriages".
In 1832 one of their steam carriages travelled via Oxford to Birmingham and Liverpool.
A June 1833 newspaper report described a demonstration in London:
 ;templatestyles src="Template:Blockquote/styles.css" / ;On Saturday last Mr Nathaniel Ogle, accompanied by several ladies, together with Mr G Burdett, Mr Macgary, Mr C Bischoff, Mr Babbage and other gentlemen, proceeded by his steam carriage from the Bazaar in King street, Portman square to call on Mr Rothschild at his residence at Stamford hill. The vehicle, although it has been rattled over the roads nearly six hundred miles, is in efficient condition. A small quantity of waste steam was perceptible at first, until the boilers and casing were hot. The distance, full seven miles, was cleared, not withstanding the crowded state of the roads, in thirty one minutes, and the sudden and narrow ascent to Mr Rothschild's made with perfect precision, which was hardly to be expected from so long and ponderous a vehicle. The party was most urbanely and kindly received by Mrs and Mr Rothschild, and after having partaken of refreshments returned to Baker street.
Early steam carriage services.
More commercially successful for a time than Trevithick's carriage were the steam carriage services operated in England in the 1830s, principally by associates of Sir Goldsworthy Gurney and by Walter Hancock among others and in Scotland by John Scott Russell. However, the heavy road tolls imposed by the Turnpike Acts discouraged steam road vehicles and for a short time allowed the continued monopoly of horse traction until railway trunk routes became established in the 1840s and 1850s.
Sir James C. Anderson and his engineering partner Jasper Wheeler Rogers were the first to bring steam-propulsion vehicles to Ireland. Rogers and Anderson created their versions of these devices in the 1830s and early 1840s where they advocated for an island-wide conveyance network that would use Ireland's mail coach roads. An 1838 Cork Southern Reporter article on Anderson's "steam drag, or carriage for common roads" recounts how Anderson and his father (both of Buttevant Castle) spent "a fortune in building twenty-nine unsuccessful carriages to succeed in the thirtieth." Jasper Rogers built his Irish steam-driven cars in a former flint-glass factory, Fort Chrystal, located on what is now known as Dublin's East Wall.
Accompanying Rogers' and Anderson's interests in improvements in Irish conveyance of goods and people, they particularly advocated steam-propelled individual vehicles because the operators, road network staff, and work crews needed to maintain the system were much more encompassing than those used by a railway system alone, at a time when Rogers and Anderson were trying to maximize Irish wage employment. They could see that their immediate competitor, the railway, would greatly diminish labor needs within Ireland's transportation infrastructures. Similarly, a national railway system would contract, rather than expand, inner-island travel destinations. Rogers' and Anderson's steam-vehicle system called for numerous way-stations for refueling and supplying fresh water, and at the same time, these stations could house a "road police" as well as telegraph depots. Essentially most Irish villages, no matter how remote, would participate in this grand steam-vehicle network. Locals would be able to earn extra money by carrying rocks to the fuel stations, rocks that would be used to build, repair, or maintain the roadways. In addition, every village would require a local road repair crew.
Military application of steam road vehicles.
During the Crimean War (1853–1856) a traction engine was used to pull multiple open trucks.
In the 1870s many armies experimented with steam tractors pulling road trains of supply wagons.
By 1898 steam traction engine trains with up to four wagons were employed in military manoeuvres in England.
In 1900 John Fowler &amp; Co. provided armoured road trains for use by the British forces in the Second Boer War.
Victorian age of steam.
Although engineers developed ingenious steam-powered road vehicles, they did not enjoy the same level of acceptance and expansion as steam power at sea and on the railways in the middle and late 19th century of the "age of steam".
Ransomes built a portable steam engine, that is a farm steam engine on wheels, hauled from farm to farm by horses in 1841. The next year Ransomes automated it and had the engine drive itself to farms.
Harsh legislation virtually eliminated mechanically propelled vehicles from the roads of Great Britain for 30 years, the Locomotive Act 1861 imposing restrictive speed limits on "road locomotives" of in towns and cities, and in the country. The "Locomotives Act 1865" (the famous "Red Flag Act") further reduced the speed limits to in the country and just in towns and cities, additionally requiring a man bearing a red flag (red lantern during the hours of darkness) to precede every vehicle. At the same time, the act gave local authorities the power to specify the hours during which any such vehicle might use the roads. The sole exceptions were street trams which from 1879 onwards