Comparative Testing of Lasers for Ride Quality Measurement on Hot-Mix Asphalt Pavements

The Texas Department of Transportation (DOT) is implementing a smoothness specification based on inertial profile measurements. For quality assurance testing, this smoothness specification includes pay adjustment schedules that are tied to the average international roughness index. The acceptance criteria used in this specification are based on surface profile measurements collected with the traditional single-point lasers, which the department has been using to monitor pavement smoothness on the state highway network. Since the Texas DOT implemented its smoothness specification, developments in sensor technology have included multipoint and wide-footprint lasers for noncontact height measurements. There is a need to verify ride quality measurements from these newer lasers to assess their impact on quality assurance tests conducted under the Texas DOT's existing ride specification. This paper presents a comparison of ride quality measurements from tests conducted with various lasers on hot-mix asphalt concrete pavements. Of particular importance to this comparison is the verification of ride quality measurements determined from the lasers tested with corresponding reference profile measurements.