What transport device did Leonardo da Vinci design that is often called the self-propelled cart?

Leonardo da Vinci designed a clockwork transport device often called the self-propelled cart.

The compact three-wheeled machine appears in a drawing from around 1478 to 1480. Springs stored energy, and a complicated system of gears and cams transferred that energy to the wheels. The cams could also control programmed movements, making the cart an early example of a machine capable of following a preset route without a person pushing it.

Because no complete original survives, historians and engineers have reconstructed the cart from Leonardo’s drawings. In 2006, a team in Florence built a full-scale working replica. The reconstructed vehicle moved, demonstrating that the mechanism could function, although it was not an automobile in the modern sense.

The cart is sometimes called the world’s first robot or car. Those labels are useful comparisons, but the machine had no combustion engine and stored motion mechanically in springs.