An experiment was carried out on the laboratory test track in which members of the public were asked to make assessments of the environmental disturbance from a number of articulated vehicles of differing weights and dimensions. For accelerating vehicles similar in appearance and noise emissions, weighing between 12 and 38 tonnes, weight differences of 6 tonnes or greater were correctly detected by the majority of subjects, but this was not the case for comparisons involving vehicles of gross weights of 32 to 44 tonnes, in which the vehicles themselves also differed. Differences in overall length of the order of 0.5 metres were not reliably detected. The TRRL quiet heavy vehicle included in the experiment was consistently rated as quieter and causing less vibration and overall nuisance, even when carrying a considerably heavier load. When loaded to 44 tonnes it was judged on average to be the same weight as a vehicle about 26 tonnes lighter. (Author/publisher)
Abstract