Leonardo da Vinci's self-propelled cart used a wooden platform and wound springs to move without being pushed by a person or animal.
Leonardo drew the cart around 1478–1480. Its front wheels were connected to steering controls, while coiled leaf springs stored energy in a way comparable to the springs in a clock. When released, the springs drove the wheels and made the cart travel forward.
The cart was probably intended for theatrical or ceremonial use rather than transportation. One famous modern interpretation suggests it may have been designed to surprise guests at court events. Because Leonardo's drawing is incomplete and some details are difficult to interpret, reconstructions differ in their mechanisms and performance.
The machine is sometimes called Leonardo's automobile, but that label can be misleading. It had no engine, fuel system, or modern transmission. It was a spring-powered mechanical vehicle, making it an important early example of autonomous motion.