Assessment of the accuracy and classification of weigh-in-motion systems: Part 2 European specification

This is the second part of a two-part paper which addresses the issue of ac curacy in weigh-in-motion (WIM) systems. The first part develops the statis tical background necessary for any system of accuracy classification applie d to a WIM system. This second part describes a draft European specificatio n for the weigh-in-motion (WIM) of road vehicles, prepared by the COST 323 management committee. The philosophy behind the specification is outlined a nd the basic structure detailed. The specification gives an indication of what WIM accuracy might be achieva ble from sites with particular characteristics. There is comprehensive revi ew of methods of calibrating and resting WIM systems. Four types of calibra tion/test condition are described for tests using statically pre- or post-w eighed vehicles. Accuracy classes are defined on the basis of the width of the confidence interval within which the measured results lie. Confidence i nterval widths are specified for gross weights and weights of individual ax les among other things. The percentage of test results which are required t o fall within the confidence intervals is a function of the test conditions and the number of test runs. Examples using real WIM data illustrate the u se of the specification.