What transport device did Leonardo da Vinci sketch with four wheels and a spring-powered drive?

Leonardo da Vinci sketched a self-propelled cart with four wheels and a spring-powered drive.

The cart appears in Leonardo’s studies from the late fifteenth century. Large coiled springs stored energy, while gears transferred that energy to the wheels. A steering system controlled the front wheels, and adjustable components could determine the cart’s route. Because it could move without an animal pulling it, the design is often described as an early precursor to the automobile.

The cart was probably intended for theatrical or ceremonial use rather than ordinary transport. Its springs could provide only limited power, and the surviving drawings do not establish every detail of its operation. A full-scale reconstruction displayed at the 2006 Florence exhibition “Leonardo da Vinci: The Mind of Leonardo” demonstrated that the basic mechanism could move when built according to the drawings.