What Leonardo da Vinci machine is often considered an early self-propelled vehicle?

Leonardo da Vinci's early self-propelled vehicle was the self-propelled cart.

Designed in the late fifteenth century, the cart used tightly wound springs to store energy. When released, the springs drove the wheels through a system of gears. Steering could be set in advance, allowing the vehicle to follow a predetermined path rather than requiring a driver to control it continuously.

The cart may have been intended for theatrical or court events, where a moving device could create a dramatic spectacle. It was not an automobile in the modern sense: it had no combustion engine, no steering wheel, and no ability to travel freely under human control. Its movement depended on stored mechanical energy.

A full-size reconstruction was built and demonstrated in the twentieth century, showing that the basic mechanism could operate. The invention is therefore best understood as a programmable spring-powered vehicle, not as the first modern car.