A roadster, sometimes referred to as a spider or spyder, is an open two-seat car with emphasis on sporting appearance or character. Initially an American term for a two-seat car with no weather protection, usage has spread internationally and has evolved to include two-seat convertibles.
The roadster is also a style of racing car driven in United States Auto Club (USAC) Championship Racing, including the Indianapolis 500, in the 1950s and 1960s. This type of racing car was superseded by mid-engined cars.
In the nineteenth century, the word "roadster" denoted a horse suitable for traveling. By the end of the century the definition had expanded to include roadworthy bicycles and tricycles.
In 1916, the Society of Automobile Engineers defined a roadster as: "an open car seating two or three. It may have additional seats on running boards or in rear deck." Additional seating in the rear deck was known as a rumble seat or a dickey seat. The main seat for the driver and passenger was usually further back in the chassis than it would have been in a touring car. Roadsters usually had a hooded dashboard.
The earliest roadster automobiles had only basic bodies without doors, windshields, or other weather protection. By the 1920s they were appointed similarly to touring cars, with doors, windshields, simple folding tops, and side curtains. When roadsters of this era were equipped with rumble seats, the seats folded into the body when not in use.
Roadster bodies were offered on automobiles of all sizes and classes, from mass-produced cars like the Ford Model T and the Austin 7 to extremely expensive cars like the Cadillac V-16, the Duesenberg Model J, and even the Bugatti Royale. They are popular with collectors, often valued over other open styles.
The term "roadster" as applied to automobiles is American in origin; before World War II, the British equivalent was a "two-seat tourer". The term was used more widely in Britain after World War II, partly through interaction with Americans during the war and partly to make the car more appealing to Americans in the time of the "export or die" policy.