What wheeled device did Leonardo da Vinci sketch as an early self-propelled vehicle?

Leonardo da Vinci sketched a self-propelled cart as an early self-propelled vehicle.

The cart appears in drawings dating to the late fifteenth century. Clockwork-like springs stored energy, and transmission components transferred that energy to the wheels. Steering could be set in advance, so the machine was able to follow a predetermined path rather than being driven by a person sitting inside it.

The cart was probably intended for theatrical or ceremonial use, possibly as a stage device. It was not an automobile in the modern sense: it had no combustion engine, driver’s seat, pedals, or modern steering system.

In 2006, a model based on Leonardo’s drawings was built and demonstrated in Italy. Scholars still discuss details of the original mechanism because Leonardo’s sketches are incomplete and use Renaissance technical notation.