Long-Term Pavement Performance Pavement Loading User Guide (LTPP PLUG)

This guide addresses the selection and use of axle loading defaults for Mechanistic-Empirical Pavement Design Guide (MEPDG) applications. The defaults were developed based on weigh-in-motion (WIM) data from the Long-Term Pavement Performance (LTPP) Special Pavement Study (SPS) Transportation Pooled Fund Study (TPF). The guide consists of two parts. The first part provides guidelines for selecting and using LTPP SPS TPF axle loading defaults with the MEPDG and DARWin-ME software. These defaults provide a source of axle loading information for pavement analysis for locations where site-specific axle load spectra are not available. The second part of the guide provides practical guidelines that States and LTPP can use to generate additional MEPDG traffic loading defaults based on their own WIM data or for specific analysis purposes. In addition, this guide contains an operator’s manual that supports the use of the LTPP PLUG software. This software helps users select site-specific or default axle loading conditions from its traffic loading library and produces axle load distribution input files for use with the MEPDG or DARWin-ME software. The software can be used to store, view, and group multiple normalized axle load spectra (NALS) and to develop MEPDG inputs and defaults using agency-provided data.