Measurement of tyre longitudinal slip-ratio is often estimated from three independent measurements devices namely wheel rotation
speed, vehicle speed and tyre rolling radius. This produces an expensive measurement system to indirectly determine the slip-ratio. This
paper presents a method by which the slip-ratio is determined from a video camera using digital image correlation techniques. The
camera, mounted in such a way that the contact patch region is captured, enables the system to measure the tyre tread speed and ground
speed at the contact patch. The slip-ratio is then determined from these two measurements.