Development of pavement smoothness index relationship

In its pursuit for providing smooth pavements, the Directorate General of Highways in Taiwan is developing and implementing ride quality specification as part of the construction assurance program. The straightedge and the profiler were used to measure pavement smoothness on 561 test sections. Probability distribution analysis showed that measurements of pavement smoothness of both devices follow the normal distribution. Smoothness specifications for construction quality control were developed for straightedge and profiler, respectively. The full-pay range is 1.36 to 2.45 mm and 2.16 to 3.65 m/km for straightedge and profiler, respectively. The smoothness relationship between straightedge and profiler was developed.