Whole-body vibration exposure experienced by motorcycle riders - An evaluation according to ISO 2631-1 and ISO 2631-5 standards

摘要

Riders of twelve motorcycles, comprising 6 full-scale motorbikes and 6 motor-scooters, and 5 sedan vehicles, performed test runs on a 20.6 km paved road composed of 5 km, 5 km, and 10.6 km of rural, provincial and urban routes, respectively. Each test run of motorcycle was separately performed under speed limits of 55 km/h and 40 km/h. Tri-axial accelerations of whole-body vibration (WBV) were obtained by using a seat pad and a portable data logger, and the driver's view was videotaped with a portable media recorder. Root mean square (RMS) acceleration, 8-h estimated vibration dose value (VDV_(8)) and 8-h estimated daily dose of static compression dose (S_(ed)) were determined from the collected data in accordance with ISO 2631-1 and ISO 2631-5 standards. Experimental results indicate that the WBV values of the sedan vehicle drivers have low RMS, VDV(8) and S_(ed) values (RMS 0.27-0.32 m/s~2; VDV_(8) 6.3-8.3 m/s~(1.75); S_(ed) 0.21-0.26 MPa). However, over 90% of the motorcycle riders had VDV_(8) (mean 23.5 m/s~(1.75))) exceeding the upper boundary of health guidance caution zone (17 m/s~(1.75)) recommended by ISO 2631-1, or had S_(ed) (mean 1.17 MPa) exceeding the value associated with a high probability of adverse health effects (0.8 MPa) recommended by ISO 2631-5. Over 50% of the motorcycle riders reached these boundary values for VDV and S_e in less than 2 h. The WBV exposure levels of the full-scale motorbikes riders and motor-scooter riders were not significantly different. However, the RMS and VDV_(8) values of motorcycle riders indicate significant roadway effect (p<0.001), while their S_(ed) values indicate significant speed limit effect (p<0.05). This study concludes that the WBV exposure levels of common motorcycle riders are distinctively higher than those of sedans, even on a regular paved road. The impact on health of WBV exposure in motorcycle riders should be carefully addressed with reference to ISO 2631-1 and ISO 2631-5. Relevance to industry: This study compares the predicted health risks of motorcycle riders according to ISO 2631-1 and ISO 2631-5 standards. Experimental data suggest that the vibration dose value of ISO 2631-1 and daily dose of equivalent static compression stress of ISO 2631-5 have roughly equivalent boundaries for probable health effects.