Leonardo da Vinci designed an odometer to record the distance traveled by a cart.
His design used a wheel whose rotations were transferred through gears to counting mechanisms. As the cart moved, the wheel covered a known distance each turn, allowing the mechanism to register the total journey. This is the same basic measurement principle used by later mechanical odometers.
Leonardo’s version was intended for land surveying and mapping. Accurate distance measurements were valuable to military engineers, architects, and mapmakers, especially when terrain made direct measurement difficult. The device could reportedly release or count a fixed quantity of small objects as the wheel turned, creating a tally of revolutions.
An odometer measures distance, not speed. A speedometer would show how fast a vehicle is moving at a particular moment, while Leonardo’s device accumulated travel over time. His design therefore belongs to the history of mechanical measurement rather than transportation alone.