LAUSR

ABSTRACT Quantification of the pavement serviceability is most often based on the international roughness index (IRI). However, in urban environments it can become challenging to drive at 80 km/h as vehicle operating speeds are much lower, among other limitations associated with the use of IRI as an indicator of ride quality in the urban context. This study was conducted to formulate an alternative pavement serviceability evaluation criteria for low-speed roads (30–60 km/h) in urban settings. Deterministic and probabilistic models were developed to predict the PSI based on the whole-body vibration (WBV) concepts, and thereafter, the results were compared with the ISO 2631 standard that addresses human exposure to multiple mechanical shocks. The ISO 2631 standard uses a WBV-based frequency-weighted root-mean-square acceleration parameter (aw ) for evaluating discomfort in a multi-axis environment. Based on the estimated models, an awz criterion of 0.98 m/s2 at a probability acceptance of 85%, for a vehicle operating speed of 50 km/h, was proposed for urban roads in this study. Overall, the study demonstrated that for accurate estimation of ride quality and comfort (i.e. PSI) of low-speed urban roads, the evaluation criteria should be based on low vehicle speeds that are more representative of urban field conditions.