US Patent 7748264 Measurement of pavement unevenness

Measuring the unevenness of a pavement surface. A frame carrying an array of sensors is transported above the pavement surface. At a first position, the distance of each sensor is measured from respective first points on the pavement surface. The measurements are repeated for subsequent positions. Calculations from the measurements determine any change in tilt. The measurements and calculations are used to derive a measure of the unevenness of the pavement surface.