What self-propelled vehicle did Leonardo da Vinci design around 1478?

Leonardo da Vinci designed a self-propelled cart around 1478.

The vehicle was a three-wheeled cart powered by coiled springs rather than by an engine or an onboard driver. Two large springs supplied motion to the driving wheels, while a programmable system of blocks and pegs controlled the cart's path. The surviving drawing is associated with Leonardo's early engineering work and is often described as a precursor to the modern automobile or a theatrical moving device.

The cart was probably intended for court celebrations or stage performances, where a vehicle could move across a set without visible human propulsion. It was not a motor car in the modern sense: it had no combustion engine, electrical motor, steering wheel, or practical road system. Reconstructions made from Leonardo's design have demonstrated that the mechanism can move, although scholars debate details of its original purpose and exact operation. Its significance is the combination of stored energy and programmable movement.