What wheeled machine designed by Leonardo da Vinci is often described as an early self-propelled cart?

Leonardo da Vinci’s self-propelled cart is often described as an early self-propelled vehicle.

Leonardo designed the cart around 1478–1480. Unlike an ordinary wagon pulled by animals, it used coiled springs to store energy. A system of gears and cables released that energy to turn the wheels, while a steering mechanism could be set for a planned route.

The cart may have been intended for theatrical performances or court spectacles rather than transport. It was compact and had no engine in the modern sense. The springs supplied limited stored power, so the machine could travel only a short distance.

The design is sometimes called the first automobile, but that description needs qualification. Modern automobiles use continuous engine power, steering controls, braking systems, and other technologies absent from Leonardo’s cart. A working replica was built and demonstrated in the 21st century, helping researchers understand how the mechanism may have operated.