What vehicle did Leonardo da Vinci design with a spring-powered mechanism for moving without horses?

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

The cart is usually dated to around 1478–1480 and is often described as an early ancestor of the automobile. Its two large rear wheels were driven by spring mechanisms, while a smaller front wheel helped with steering. The design may have been intended for theatrical use or ceremonial demonstrations.

Leonardo’s surviving drawing does not provide every construction detail, so modern reconstructions have tested different interpretations of its mechanism. The cart was not powered by an engine, battery, or steam. Its significance lies in using stored mechanical energy to create controlled movement, a principle that also appeared in clockwork and automata.