New Mechanistic–Empirical Approach for Estimating the Effect of Roughness on Vehicle Durability

Abstract

Vehicle manufacturers place a major focus on improving the design of vehicle components to respond better to changes in road surface profiles. Nevertheless, changes in the surface profile still directly affect user costs including repair and maintenance (R&M) costs and damage to goods. For example, AASHTO reported that poor road conditions added an estimated $76.8 billion to transport costs annually. The objective here is to estimate the effect of roughness, as expressed by the international roughness index, on vehicle durability and R&M costs. First, the R&M costs of Zaniewski et al. (the latest comprehensive research conducted in the United States) are updated by multiplying their reported costs by the inflation rate of R&M costs between 1982 and 2007. Then a mechanistic–empirical (M-E) methodology is proposed to estimate the effect of roughness on R&M costs. The proposed approach is based on fatigue damage analysis by using numerical modeling of the vehicle response. Finally, the results from the M-E approach are compared with the empirical results (updated Zaniewski tables) and found to be very close up to 5 m/km. The standard error is about 2%. Also, a case study of the I-69 section near Lansing, Michigan, is presented. This detailed analysis is useful for identifying those segments of the road within a project that cause higher operating costs to the traveling vehicles. These localized rough sections could then be subject to maintenance activities in order to remedy the problem.