Performance Model and Conceptual Framework for Pavement Smoothness Specification (05-0922)
Richard M. Weed, Consultant, France

This paper describes the development of a prototype statistical acceptance procedure for hot-mix asphalt (HMA)pavement smoothness based on the International Roughness Index (IRI). The new procedure is a performance-related specification (PRS) based on a mathematical model relating expected life to initial smoothness as measured in terms of percent defective (PD) applied to IRI measurements computed from the pavement profile. Life-cycle cost analysis (LCCA) has been used to set payment levels in proportion to the present value of quality received. In addition to pay reductions for excessive roughness, a bonus provision is recommended to reward contractors whose extra attention to quality control has produced a superior riding surface that provides additional benefits to both the agency and the motoring public. It is expected that this prototype specification will be simulated without pay adjustments on one or two trial projects before being refined and implemented on a series of pilot projects as actual pay adjustments are phased into use.