Even with a WIM system calibrated, there is some variability in the measurements. In order to better estimate the number of overweight vehicles and collect data for future pavement design, the WIM systems need to be characterized with respect to their variability. For the purpose of the problem statement, the term overweight vehicle is defined as vehicle is overweight by gross weight, group weights and/or the pounds per inch of manufactures tire width. Tire widths and axle spacing are used to determine legal limits for overweight axles, WIM systems have no means of determining tire width, needed to determine the legal load limit.
Research is needed in order to calibrate our WIM systems and get an estimate of the number and magnitude of overweight vehicles.