What type of road vehicle did Leonardo da Vinci design with spring-powered motion?

Leonardo da Vinci designed a self-propelled cart with spring-powered motion.

The cart's propulsion came from coiled springs rather than steam, fuel, or an animal pulling it. Gears transmitted the stored energy to the driving wheels, while a steering arrangement guided the vehicle. The mechanism could be set in advance, giving the cart a limited programmed journey.

Leonardo's drawings suggest that the cart may have been created for theatrical performances at an Italian court. A moving prop could surprise an audience or carry scenery without visible human assistance. That likely purpose explains why the machine was compact and why its travel distance did not need to match that of a practical transport vehicle.

The cart is sometimes confused with Leonardo's other transportation sketches, but it is the spring-driven machine specifically identified as self-propelled. Calling it an automobile is useful as a comparison, not as a literal technical description: automobiles use engines and modern control systems.