What mechanical device did Leonardo da Vinci design to move a cart without horses?

Leonardo da Vinci designed a self-propelled cart to move without horses.

The cart, usually dated to the late fifteenth century, used coiled springs hidden inside its wooden body as a source of stored energy. Cords connected the springs to wheels, allowing the mechanism to drive the cart forward. Adjustable cams helped determine the route, making the machine more than a simple rolling vehicle.

The device is often called a precursor of the automobile, but it was not powered by an internal-combustion engine. It was a clockwork-style machine powered by wound springs. It may have been intended for theatrical performances or court spectacles, where a vehicle could move across a stage without visible animals or a driver.

A full-scale replica built in the twentieth century demonstrated that the design could operate. Researchers have also noted that the surviving drawing does not reveal every construction detail, so modern reconstructions necessarily involve interpretation. Its importance lies in combining stored mechanical energy, steering, and autonomous motion.