Evaluation of Road Roughness and Vehicle Speed Effects on Vibration Comfort of School Bus Driver Seats following the ISO 2631-1 Standard and Occupational Health and Safety Legislation

Abstract

papers available in the literature. In this study, the maximum vehicle speed is predicted for the comfortable driving of school bus drivers under certain working conditions. First, a full-vehicle school bus model, which consists of a seat, vehicle body, wheels, and suspension systems, is developed to evaluate vehicle seat comfort following ISO 2631-1 and Occupational Health and Safety (OHS) legislation. Second, the experimentally collected power spectrum densities of road roughness are converted to amplitude form in order to be an input to the developed full-vehicle model. Third, the frequency weighting factor, which is determined by ISO 2631-1, is applied to the calculated RMS acceleration of the seat. Finally, frequency-weighted RMS accelerations of the seat for various conditions of road roughness and vehicle speeds are obtained, and they are used to evaluate the bus driver seat comfort by ISO 2631-1. In addition, RMS accelerations of the bus driver seat are used to evaluate vehicle seat comfort by OHS legislation. It is concluded that the effects of vehicle speed and road roughness on comfortable driving are observed, and maximum vehicle speed for comfortable driving decreases as the power spectrum density of road roughness increases. According to the results, measures to be taken following the OHS legislation are suggested.