Leonardo da Vinci designed a self-propelled cart that could move without being pushed by people or animals.
The cart used coiled springs as its stored energy source. As the springs unwound, gears transferred motion to the wheels. A steering system could be set in advance, allowing the vehicle to follow a programmed route rather than being continuously guided by a driver.
Leonardo’s drawing dates from around 1478 to 1480. It was probably intended for theatrical or ceremonial use, such as creating a moving effect at a court event, rather than for ordinary transportation. A modern reconstruction in 2006 showed that the mechanism could work when built from the surviving design.
The cart is often called an early automobile, but it had no engine and could not travel indefinitely. Its spring-powered mechanism makes it closer to a programmable mechanical vehicle.