What transport machine did Leonardo da Vinci design with a spring-powered propulsion system?

Leonardo da Vinci designed a self-propelled cart powered by coiled springs.

The cart is usually dated to around 1478–1480 and is described as one of the earliest concepts for a programmable or autonomous vehicle. Two large springs stored energy and released it through a system of gears. A steering mechanism could be set in advance, allowing the cart to follow a predetermined path rather than being driven continuously by a person.

The machine was probably intended for theatrical use at court, such as moving scenery or appearing to travel by itself. It was not a motor car: internal-combustion engines and practical road vehicles came centuries later. The cart’s importance lies in its combination of stored mechanical energy, gearing, and preset control. In 2006, a replica was built and demonstrated at the Museo Galileo in Florence, helping researchers investigate how the mechanism may have worked.