Pavement Roughness, Measurement and Evaluation

Abstract

VERTICAL ACCELERATIONS OF A PASSENGER TRAVELING IN AN AUTOMOBILE ON A SECTION OF ROAD AT 51.5 MPH (23.0 M/S) ARE AUTOMATICALLY SUMMED. A ROUGHNESS INDEX IS OBTAINED BY DIVIDING THIS SUM BY THE TIME ELAPSED DURING THE TEST. CONTINUITY IN MEASUREMENTS SINCE 1957 HAS BEEN PRESERVED THROUGH CORRELATIONS AMONG SUCCESSIVE VEHICLES INVOLVED AND REFERENCE PAVEMENTS. IN GENERAL, BITUMINOUS CONSTRUCTION HAS SMOOTHER RIDING SURFACES THAN CONCRETE CONSTRUCTION. THE SMOOTHNESS OF CONCRETE PAVEMENTS, HOWEVER, HAS IMPROVED ON THOSE PROJECTS WHERE SLIP-FORM PAVING WAS USED. INTERSTATE HIGHWAY AND PARKWAY CONSTRUCTION CONTINUES TO YIELD SMOOTHER PAVEMENTS THAN OTHER MAJOR CONSTRUCTION. THE RATE OF INCREASE IN ROUGHNESS WAS FOUND TO BE DIFFERENT FOR EACH PAVEMENT TYPE AND VARIED ACCORDING TO THE ORIGINAL OR AS-CONSTRUCTED ROUGHNESS OF THE PAVEMENT, STRUCTURAL NUMBER, AND TYPE OF HIGHWAY FACILITY INVOLVED.