Abstract: The present invention relates to measuring techniques intended to determine the operational characteristics of a road pavement by assessing the braking conditions of transport vehicles. The device comprises a single-axle trailer whose frame is coupled by a tow pole to a towing vehicle. The trailer has only two wheels adapted for rotating on the moving trailer with longitudinal slipping in opposite directions. The device also comprises a recording instrument with a sensitive element which is located between the trailer frame and the free end of the pole and is kinematically linked therewith in such a manner that on the moving trailer the sensitive element is acted upon by a force which is proportional in magnitude to the sum of absolute values of the longitudinal traction forces acting on the wheels and is directed essentially parallel to the forces.