An investigation is described of the riding comfort in long-distance coaches and heavy goods vehicles, operating over typical trunk road surfaces. Ride, represented by the root-mean-square (rms) of the vertical acceleration at the seat-person interface, has been measured in both coaches and lorries and correlated with riding comfort assessments of drivers and passengers. Comparisons are made with the ride in cars measured in previous experiments. Results show that coach passengers and lorry drivers will tolerate higher acceleration levels more readily than will car occupants. Psychological factors, as well as vibration levels influence the subjective assessment of ride. Evaluation of the highest measured acceleration levels against recommended international standards of human response to whole-body vibration show a possibility that lorry drivers could, in certain cases, suffer some fatigue-decreased proficiency within their present legally permitted periods of continuous driving. The ride in lorries could be improved by the more widespread use of suspension seats. (Author/publisher)
Abstract