What transportation device did Leonardo da Vinci sketch with a spring-powered mechanism and three wheels?

Leonardo da Vinci sketched a three-wheeled self-propelled cart with a spring-powered mechanism.

The design dates to the late fifteenth century and is recorded in drawings from the Codex Atlanticus. Two rear wheels received power from coiled springs, while a smaller front wheel helped guide the vehicle. Programmable control devices allowed the cart to follow a predetermined path, making it an early example of mechanical automation.

Leonardo may have intended the cart for theatrical performances or court celebrations rather than road transport. Because the original drawing does not show every internal detail, modern builders have had to interpret parts of the mechanism. A replica was constructed in the early 2000s for an Italian television program and demonstrated movement.

The cart is often called the world's first robot or automobile, but both labels require caution. It had no engine, steering system, or practical road design in the modern sense. “Self-propelled cart” is the more precise historical description.