WIM Site Selection

General Principles

According to the ASTM-E1318, WIM users must provide and maintain an adequate operating environment for the system to perform properly. Factors that influence the performance of a WIM system are the road geometry and pavement condition of the roadway and the overall site location. These factors influence the dynamic behaviour of the vehicle and thus influence the accuracy of the…
Read more...

Culway Site Selection Criteria

Road Geometry The selection of a suitable location for a Culway installation is critical to the accuracy of the information collected. The following criteria are recommended when assessing the suitability of road geometry for Culway: Straight alignment should have a minimum of 120 metres at each side of the culvert. Longitudinal grade preferably should be less than 1% but not…
Read more...

Bending Plate Site Selection Criteria

The location on the bending plate affects the accuracy of the data recorded. At the site of the bending plate, trucks should not be encouraged to straddle the WIM scale by partially driving on the shoulder. To prevent straddling, the plate should be installed at a guardrailed section or one immediately after. If guardrail is not available an additional weigh…
Read more...

Capacitance WIM Site Selection Criteria

There are two main applications for capacitance WIM: statistical and pre-selection (screening). Statistical applications are for normal WIM measurement in a traffic stream. Pre-selection applications usually take place on specially constructed screening lanes. Road Geometry For statistical WIM sites within the traffic stream A minimum lane width of 3.0 m with at least 1.0 m hard shoulder is required. Maximum…
Read more...

Piezoelectric WIM Site Selection Criteria

The essential characteristics of a road suitable for site selection are the surface condition, road materials, road thickness, latitudinal and longitudinal slope, road curvature, rutting and cracking. Therefore not only the longitudinal evenness but also the deteriorations (such as rutting, deformation, cracking etc.) limit the accuracy of a measurement, and may reduce the sensor durability or affect its response. The…
Read more...