IT IS ONLY NATURAL THAT THOSE INTERESTED IN THE BUILDING AND MAINTENANCE OF HIGHWAYS SHOULD SEEK TO DEVELOP TOOLS WITH WHICH TO MEASURE HIGHWAY SURFACE SMOOTHNESS OR ROUGHNESS. THIS REPORT CONSIDERS EXISTING METHODS AND CERTAIN INHERENT CHARACTERISTICS OF SUCH METHODS WHICH PRECLUDED THEIR GENERAL ACCEPTANCE. THE STANDARDIZABLE EQUIPMENT DESCRIBED IN THE PAPER OPERATES ON THE PRINCIPLE OF THE MEASUREMENT OF THE VERTICAL OSCILLATION OF A WHEEL SUSPENSION WITH RESPECT TO ITS SUPPORTED FRAME. IN EARLIER APPLICATIONS OF THIS PRINCIPLE IT WAS RECOGNIZED THAT DIFFICULTIES WERE CAUSED BY THE USE OF AN APPARATUS, IN WHICH THE MOTOR VEHICLE AND ITS LOAD ARE A COMPONENT PART, AND THIS RECOGNITION LED TO AN INVESTIGATION OF THE USE OF A SPECIAL VEHICLE CAPABLE OF STANDARDIZATION IN ALL ITS PARTS. THE NEW EQUIPMENT IS IN THE FORM OF A SINGLE WHEEL SEMI-TRALER, ATTACHABLE TO ANY TOWING VEHICLE, AND IS DESIGNED AS A HORIZONTAL PENDULUM WITH THE AXLE OF THE WHEEL PLACED AT THE CENTER OF PERCUSSION. THE GROSS WEIGHT OF THE ENTIRE VEHICLE IS 740 LBS. A SPECIAL FEATURE OF THE EQUIPMENT IS THE INCORPORATION OF A NEWLY-DESIGNED OVERRUNNING CLUTCH INTEGRATOR WHOSE OPERATING CHARACTERISTICS ARE REMARKABLY CONSTANT. ALL CONNECTIONS TO THE INSTRUMENT BOARD IN THE TOWING VEHICLE ARE MADE ELECTRICALLY. THE PERFORMANCE CHARACTERISTICS AND RECOMMENDED STANDARD OPERATING PROCEDURE ARE GIVEN IN DETAIL. MANY HUNDRED MILES OF OPERATION, WITHOUT MECHANICAL FAILURE, INDICATE ADEQUATE MECHANICAL DESIGN. IT IS EASY TO USE AND THE DATA ARE OBTAINED RAPIDLY WITH IT. /AUTHOR/