About WIM

Overview

Austroads defines WIM as a device that measures the dynamic axle mass of a moving vehicle to estimate the corresponding static axle mass. That is, the WIM device captures and records the axle or axle group mass, hence GVM as the vehicle is moving. WIM systems should not be confused with on-board vehicle weighing systems. On-board weighing systems are mounted…
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Vehicle Mass

From a pavement wear perspective vehicle mass is often expressed in terms of the number of ESA loads. ESAs are a measure of the relative pavement wear of the load of individual axles or axle groups compared to a standard reference load. An example of a standard axle load in Australia is the reference load of 8.15 tonnes on a…
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System Components

WIM systems generally comprise the following basic components: vehicle classification and/or identification sensor vehicle classification and/or identification sensor processor and data storage unit user communication unit Figure: Components and layout of a typical WIM system Mass Sensor The mass sensor (and the output signal it produces) is the most fundamental and important component of a WIM system. The other components…
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Specifications

American Society for Testing Materials ASTM has established a Standard Specification for Highway Weigh-in-motion Systems E1318 which is used by most WIM users around the world as a guideline. The latest revision was published in February 2009. The Standard has about 20 pages of specifications covering: definitions four different types of WIM systems (Type I, II, III and IV) and…
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