Environmental effects on driver acceleration exposure

by 1975- Khanal, Shekhar

The European Union has developed a set of standard for the exposure to whole body vibration measured by acceleration. For manufacturers to meet this directive, it is essential to understand the levels of exposures that are common among long-haul vehicle drivers. Many factors can influence the exposure levels. Generally, all the European vehicles are the cab-over design. Each vehicle manufacturer has provided a combination of truck and cab suspensions in addition to the air-ride seating that is standard on the vehicles. The road quality, driver speeds, and time of daily work can have variation from country to country. The determination of the factors that influence the driver exposure and their level of effects are necessary. Effect of road type, vehicle type, load, different drivers, and different environment on the whole body vibration exposure to the European truck drivers was investigated in this study. Data collected from Europe on different types of trucks were processed and analysed as per the methods set by the International standard ISO 2631-1 and the results were compared with the limits set by the directive of the European Community- 2002/44/EC. The first set of data was taken from driver’s seat, passenger’s seat and floor of 2 cab-over trucks (Volvo and Mercedes) in England on different roads and load conditions. A second set of data was collected from 6 different cab-over trucks (DAF, Volvo, Iveco, Mercedes, Renault and Scania) in Poland on a wider variety of roads, with the application of additional transducers on driver’s & passenger’s seat back as well as seat motion sensors. Further analysis on cab rotation and jerk was made. The results were compared among different factors. Road type was the primary factor affecting the driver’s exposure followed by the truck load. Choice of the proper processing equipment made some differences in the results. Discrepancies were also observed in assessing the WBV with different methods suggested in the standard. The driver was found to be safe as per the ECE directive but the comfort levels were often exceeded. For both studies, the level of comfort was in ‘fairly uncomfortable’ range suggested by the ISO standard. Passenger was always exposed to higher level of vibrations. Significant amount of cab rotations and lots of jerks as well as greater levels of acceleration exposure were observed in the Poland test trucks. v