What self-propelled vehicle did Leonardo da Vinci sketch as an early automobile concept?

Leonardo da Vinci sketched a self-propelled cart, often described as an early automobile concept.

The vehicle appears in Leonardo’s notebooks as a three-wheeled cart powered by coiled springs. When wound, the springs could drive the cart’s wheels through a system of gears. A steering mechanism could also be set in advance, allowing the cart to follow a predetermined route.

Leonardo probably designed the machine around the end of the 15th century. Its original purpose is uncertain: it may have been intended for theatrical effects, court entertainments, or practical experimentation. It was not a motorcar in the modern sense, because it had no internal-combustion engine and could not be freely steered during travel.

A reconstructed version was built in the 21st century using Leonardo’s surviving drawings. The reconstruction helped demonstrate that the mechanism could move, although questions remain about details Leonardo left unspecified.