What spring-powered vehicle did Leonardo da Vinci design to move without a driver?

Leonardo da Vinci designed a self-propelled cart to move without a driver.

The cart was powered by coiled springs hidden inside its body. When wound, the springs released energy through a system of gears, turning the wheels. The design is often described as an early ancestor of the modern automobile, although it was intended mainly for theatrical performances rather than ordinary transportation.

Leonardo’s surviving drawings do not show every construction detail, so modern reconstructions have helped test how the mechanism could have worked. In 2006, an Italian team built a working model based on his drawings. The cart could travel a limited distance and follow a preset route using a steering system.

It is sometimes called a “robotic cart,” but that name can cause confusion with Leonardo’s later mechanical knight. The cart was a wheeled automaton, not a passenger vehicle with an engine.