Cugnot was born in Poid , Meuse, Lorraine. He trained as a military engineer. He experimented with working models of steam engine powered vehicles for the French Army, intended for hauling heavy cannons, starting in 1765.
Cugnot seems to have been the first to convert the back-and-forth motion of a steam piston into rotary motion. A functioning version of his "Fardier à vapeur" ("Steam wagon") ran in 1769. The following year he built an improved version. His vehicle was said to be able to pull 4 tonnes and travel at speeds of up to 4 km per hour. The heavy vehicle had two wheels in the back and one in the front, which supported the steam boiler and was steered by a tiller. In 1771 his vehicle crashed into a brick wall, the first known automobile accident. The accident together with budget problems ended the French Army's experiment with mechanical vehicles, but in 1772 King Louis XV granted Cugnot a pension of 600 francs a year for his innovative work.
With the French Revolution Cugnot's pension was withdrawn in 1789, and the inventor went into exile in Brussels, where he lived in poverty. Shortly before his death he was invited back to France by Napoleon Bonaparte. Nicolas-Joseph Cugnot returned to Paris, where he died.
Nicolas-Joseph Cugnot's 1770 machine is preserved in Paris' Conservatoire des Arts et Metiers.
- Cugnot on 3wheelers.com with picture of the Steam Tractor