WIM Technologies

Overview

This section of the site provides an overview of the main WIM technologies/systems in the Australian and New Zealand market: Culway Plate-in-Road - Bending Plate Plate-in-Road - Capacitance WIM Piezoelectric WIM. It includes information about data accuracy and system life span, guidelines on the selection of WIM technologies, and examples of WIM data logging and classification systems in use.
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Culway

MRWA developed a bridge based strain gauge system called AXWAY in the 1980s. Experience with AXWAY led MRWA, in conjunction with ARRB, to develop Culway (Austroads 2000). With Culway, strain gauges were mounted onto a culvert rather than a bridge (as shown in the figure below). Figure: Culway site and Culway II data logger Source: ARRB Culway has been installed…
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Plate-in-Road: Bending Plate

Invented and designed by the Bundesanstalt fuër Strassenwesen (BAST), Cologne, Germany in the late 60s, bending plate technology has been widely used in numerous long-term traffic and pavement monitoring programs. NZTA is using the PAT bending plate technology at four TMS sites and two further sites at the Auckland Harbor Bridge for special studies with a total of 20 lanes.…
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Plate-in-Road: Capacitance WIM

The main components of a capacitance WIM system (also known as capacitive WIM system) are: a traffic data logger inductive loops (two per lane) capacitance weigh sensors (one or two per lane) optional piezo axle detectors to enhance detection of very light axles and provide detection of axles in lanes where no WIM sensor is installed. Configuration options chosen for…
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Piezoelectric WIM

Piezoelectric WIM is also widely used in Australia. A piezoelectric WIM system generally consists of at least one piezoelectric sensor and at least one inductive loop, embedded in road cuts or it may be portable. (Kistler piezoelectric sensors are encapsulated in an epoxy-filled metal channel, usually made of aluminum.) Figure: A piezoelectric WIM site Source: Kistler 2004 All piezoelectric sensors…
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Data Accuracy and Life Span

Accuracy in terms of WIM refers to the closeness between a quantity measured or estimated by a WIM system and a known, accepted value. It is best practice to decide the necessary accuracy needed before deciding the type of WIM to purchase. The ASTM establishes functional requirements for WIM accuracy. Austroads Guide to Traffic Management Part 3: Traffic Studies and…
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Technology Selection

The selection of WIM technologies depends on the purpose and usability of the output data, data accuracy requirements, road environment such as pavement type, number of lanes, traffic volume, power and communication requirements, costs of equipment, installation, maintenance and data storage, on-going support from vendors and in-house road agency expertise. Some broad guidelines for selecting WIM systems include: Culway is…
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Data Logging and Classification Systems

This section provides some examples of WIM data logging and classification systems including ViperWIM Classifier, RAKTEL 8010 Universal Traffic Event Logger, and Hi-Trac 100 High-Speed Traffic WIM and Classification System. ViperWIM Classifier The ViperWIM Classifier is manufactured by Applied Traffic in the United Kingdom and contains sensor interface hardware with high resolution and accuracy. It also has 2 GB of…
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