Cugnot, Nicolas-Joseph

French engineer who produced the first high-pressure steam engine and, in 1769, the first self-propelled road vehicle. Although it proved the viability of steam-powered traction, the problems of water supply and pressure maintenance severely handicapped the vehicle.

While serving in the army, Cugnot was asked to design a steam-operated gun carriage. After several years, he produced a three-wheeled, high-pressure carriage capable of carrying 1,800 litres/400 gallons of water and four passengers at a speed of 5 kph/3 mph. Although he worked further on the carriage, the political upheavals of the French revolutionary era obstructed progress and his invention was ignored.