Traffic Management and Network Operations

WIM is a major tool used to collect traffic data. WIM equipment provides highway planners and designers with traffic volume and classification data by time of day and day of week.

In addition, WIM equipment also provides planners and designers with ESAL that heavy vehicles place on pavements.

Motor vehicle enforcement officers use heavy truck axle load data to plan enforcement activities.

The intended use of WIM data should determine the approach each state and territory chooses in developing WIM data collection sites and the resources required to maintain sites over the expected site design lives.

Austroads 2004 recommended as a good practice that traffic data from counting stations, manual counts, WIM sites and signal systems be integrated as a first step.

Other data to follow should include Austroads National Performance Indicators, road management data, crash rates and others. By integrating these different types of data, traffic agencies can monitor the road network performance more accurately and efficiently.

WIM sites can provide classified counts, GVM and AGM, with some WIM systems also providing individual axle load information.

WIM sites are mainly located on major freight corridors, and many are permanent sites, e.g. Culway sites. These counting sites can be used to calculate AADTs if all lanes of traffic are monitored.

They can be treated as pattern stations, although they may not be at the best statistically representative locations. Short-term WIM sites can certainly provide an extra sample of counts to supplement current short-term stations. A good practice is therefore treating them as part of an integrated traffic counting program.

See also: Correlation of Traffic Composition and WIM Data


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