What self-propelled vehicle did Leonardo da Vinci design using springs and steering controls?

Leonardo da Vinci’s spring-powered vehicle with steering controls is known as the self-propelled cart.

Leonardo designed the cart around 1478–1480. It used coiled springs as an energy source, much like an oversized clockwork mechanism. The springs drove the wheels through gearing, while a programmable control system could determine the cart’s path. The surviving drawings also show a steering mechanism and a braking arrangement.

The cart was probably intended for theatrical performances or court spectacles rather than transport. It could move without someone visibly pushing it, making it a striking stage effect in a Renaissance court. Unlike an automobile, it had no engine, fuel system, or passenger cabin designed for ordinary road travel.

The design was reconstructed in modern times by researchers and museum teams. Those reconstructions demonstrated that the mechanism could operate, although details of the original drawings leave room for interpretation. The cart is therefore an important early example of a self-moving machine, but it was not a petrol-powered car or a practical road vehicle.