Abstract: A method of controlling the sideways motion of a trailer forming part of a combination vehicle, such as a road train, for road transport of heavy goods. The vehicle has a trailer including a semi-trailer body and a dolly mounted beneath the front of the semi-trailer body. The method includes steering at least some of the wheels on said axle sets relative to the dolly frame such that at high speeds, as the vehicle turns towards one side, steering the dolly wheels to induce the dolly to move towards that side and, at low speeds, as said vehicle turns towards that side, steering the dolly wheels to induce the dolly to move towards the opposite side.

Abstract: 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.