In order to improve the accuracy of weigh-in-motion

the effective way of selecting sampling points is presented to reduce error.A digital filter is designed with FIR and simulated with Matlab software.After filtering

the weight signals higher than 3 Hz and all kinds of disturbing signals are eliminated when the car passing through the scales

and then the effective data are picked up accurately.The criterion of 3 standard deviation is used to remove gross errors

and then the data are averaged as the measured weigh-in-motion value.The experimental results show that

by choosing the effective sampling points

the accuracy of dynamic automotive value at 50% load can reach 1%.