Truck Traffic and Truck Axle Load Spectra on Interstate Highways for Mechanistic-Empirical Pavement Design

Accurate truck traffic information is essential for generating appropriate pavement designs with the American Association of State Highway and Transportation Officials (AASHTO) Mechanistic-Empirical Pavement Design Guide (MEPDG) methodology. As traffic volumes and traffic compositions continuously change, the truck traffic and axle loads must be updated periodically to provide accurate input for pavement design with MEPDG. This paper presents the results of an effort to obtain the magnitudes and distributions of truck traffic on interstate highways from the weigh-in-motion (WIM) and automatic traffic recorder (ATR) data in Indiana. The truck traffic features include annual distribution, seasonal distribution, weekly distribution, hourly distribution, and directional distribution, and axle weight distributions. The axle load spectra are calculated and displayed for single axle, tandem axle, and tridem axle arrangements of all types of buses and trucks.