Weigh-in-motion (WIM) systems are devices which measure the loads imposed by the axles of vehicles travelling at normal highway speeds. Their main limitation is their poor accuracy in determining static axle and gross vehicle weights. A major reason for this is that vehicles bounce on their tyres and suspensions as they travel at speed. The accuracy of WIM systems may be improved by the use of multiple-sensors. An array of 9 weigh-in-motion sensors was installed in the TRRL research track and tested using a variety of vehicles travelling at a range of speeds. The tests showed that the use of the array reduced the coefficient of variation (CoV) of the gross weight impact factor (gross weight measured using the WIM divided by gross weight measured using an enforcement weighbridge) from, on average, 8.8 per cent using only one sensor to 3.6 per cent using the average from 9 sensors. (A)
Samenvatting