Predicting Vertical Acceleration in Vehicles through Road Roughness

This study investigated the use and suitability of the International Roughness Index (IRI) for predicting vertical acceleration in truck shipments at recommended highway speeds. The investigation resulted in the development of a mathematical procedure for predicting the expected power‐spectral‐density (PSD) vertical acceleration at a specific location on the truck bed as a function of IRI, pavement type and age, dynamic characteristics of the vehicle, and speed of travel. The data for this study were collected from 20 different sections of highway pavements using two devices: a profilometer, which recorded elevation profiles of the pavement sections, and an accelerometer, which measured the vertical acceleration in the rear of a tractor semitrailer truck bed traveling at one of three different speeds. A major result of this study is procedure for estimating the PSD vertical acceleration in the rear of the truck bed for selected pavement categories and truck speeds using only the pavement IRI and the vehicle transmissibility characteristics.