What self-propelled vehicle did Leonardo da Vinci design in a 15th-century manuscript?

Leonardo da Vinci designed a self-propelled cart as a programmable mechanical vehicle.

The cart appears in drawings from the late 15th century, especially in the Codex Atlanticus. Springs wound inside the vehicle supplied power, while a system of gears controlled its movement. Pegs placed on the transmission helped determine the route, making the design an early example of programmable automation.

The machine is often called Leonardo's automobile, but it was not powered by an engine or intended for road transport in the modern sense. It was probably designed for theatrical or ceremonial use, perhaps to move across a stage. Modern reconstructions have shown that the mechanism can operate when built from the surviving drawings.

The vehicle is also associated with Leonardo's robot designs, although the cart and the later humanoid robot are separate machines. Its importance lies in combining stored mechanical energy, gearing, and automatic control centuries before motor vehicles appeared.