ABSTRACT
For last decades, a static and low speed weigh-in-motion (WIM) systems have been used to enforce the weight limit on the roadway. Since the weight control is of prime importance for the maintenance of the roadway, the Korea Expressway Corporation (KEC) has been controlling the traffic weight using the static and low speed WIM systems. However, these systems require a weighing station to slow down or even to stop the freight truck for the weight measurement. When the truck is stopped or at low speed, the truck driver could tamper with the axle configuration and trick the actual weight. Therefore, there is a need to develop a WIM system to measure the weight at higher speed as the same accuracy as low speed WIM. The objective of this study is to develop a new high speed WIM (HS-WIM) system to enforce the overweight truck running on the mainline of expressway. There are two major requirements to use the HS-WIM for the enforcement; one is to provide the truck configuration and classification at higher accuracy, and the other is to provide the truck weight at higher accuracy. In this study, two diagonal sensors were used to satisfy the former requirement and the temperature differential and weight configuration were considered to fulfill with the later requirement. To provide the accurate truck configuration and classification, two diagonal sensors were instrumented separately at 45° on each side from the center of a lane, and each diagonal sensor determines the location of each tire imprint and provides the number of tires per axle. This layout of diagonal sensors eliminates various error that occurred with single diagonal sensor layout, and therefore the HS-WIM system is able to classify the truck configuration and classification according to the new vehicle classification structure developed by the Korean government. To minimize the error in measuring the weight and to provide the accurate truck weight, two different factors were considered and the correction methods were developed. One factor is the tire location in transverse direction and the other factor is the temperature differential between the top and bottom pavement. When two correction methods were applied, the results show that the error of gross vehicle weight (GVW) was reduced by 5%. As a result, the HS-WIM system is fulfilled with the COST-323 Specification, the new system is capable to enforce the overweight truck in Korea. Change in error rate after correction using double diagonal sensors. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315207681/cd556cd4-4dcf-4efe-8e29-56fc67b8bfbd/content/fig138_1.tif"/>
