What self-propelled device did Leonardo da Vinci design as an early predecessor of the automobile?

Leonardo da Vinci designed a self-propelled cart as an early predecessor of the automobile.

The cart was drawn around 1478–1480 and used coiled springs to store energy. When released, the springs drove the wheels through a system of gears. Steering could be programmed by setting blocks inside a drum, making the device capable of following a predetermined path rather than being continuously guided by a driver.

Because it moved without being pushed or pulled by an animal, the cart is often described as the world’s first self-propelled vehicle. It was not a modern car: it had no combustion engine, passenger cabin, brakes, or practical road system. The surviving drawing also leaves some construction details open to interpretation.

A replica built in the 21st century demonstrated that the mechanism could work. The cart may have been intended for theatrical effects or court spectacles, showing how Leonardo applied mechanical engineering to entertainment as well as military and scientific problems.