The Cugnot tractor is believed to be the first self-propelled road vehicle, and thus, the earliest automobile. Powered by steam, the three-wheeled tractor was invented in 1769 by Nicolas-Joseph Cugnot. It was designed to carry artillery, but similar vehicles soon found many other uses in industry.
In the 15th century, Italian inventor Leonardo da Vinci envisioned possibilities for power-driven vehicles. By the late 17th century, English physicist Sir Isaac Newton had proposed a steam carriage, and by the late 18th century French army captain Nicholas-Joseph Cugnot had actually built one. By the mid-1800s, the popularity of steam vehicles began to decline because they were dangerous to operate and difficult to maintain. At about the same time, inventors became interested in the internal-combustion engine.
Robert Street of England filed a patent in 1794 that summarized how an internal-combustion engine might work, but it was Belgian-born French inventor Jean-Joseph-Étienne Lenoir who built the first commercially successful internal-combustion engine in 1859. Lenoir’s engine had a carburetor that mixed liquid hydrocarbons, which formed a vapor. An electric spark in a cylinder ignited the vapor. By 1876 German shop clerk Nikolaus August Otto had improved on Lenoir's engine, and the Otto engine became the model of the internal-combustion engines used today. Germans Gottlieb Daimler and Karl Benz attached motors to tricycles and automobiles, building what are regarded as the first modern cars in 1885 and 1886 (DaimlerChrysler AG).
In America, lawyer George Baldwin Selden studied many of the European engines at the Philadelphia Centennial Exposition of 1876, then redesigned what he considered to be the best among them. He reduced the engine weight so it could power a light road vehicle. Selden patented his engine, so he ultimately received a royalty, or small payment, for almost every car made in the United States.
Charles Edgar Duryea and his brother Frank are credited with the first production automobile made in the United States. Their small company produced 13 cars in 1896, ushering in the automobile industry. Only a few more cars were sold in the following year, and the brothers split up to follow separate interests.