Weigh-in-motion (WIM) systems consist of sensors placed in road pavements to measure the weight of vehicles passing over them, along with other data such as speed, axle load and spacing, and vehicle type. This data is used to enforce weight limits on trucks and is also useful in a wide range of other applications, such as pavement design and traffic analysis.

However, constructing and maintaining permanent roadside WIM stations is expensive, so these systems are installed primarily on roadways with heavy traffic, such as interstate and trunk highways, and rarely used for rural local roads. Meanwhile, heavy truck volumes on local roads are increasing, significantly shortening their lives. A less costly, portable WIM system is needed for such roads so that collected data can be used to better design these roads to accommodate heavy truck traffic.

One solution for bringing WIM technology to local roads is to implement a portable, reusable system similar to pneumatic tube counters used to conduct traffic counts. With funding and technical assistance from MnDOT and the Local Road Research Board, Professor Taek Kwon of the University of Minnesota—Duluth has developed a prototype system that has already proven to be nearly as accurate as the more expensive, permanent systems.  MnDOT Research Services staff drove up to MnROAD this week to observe a live demonstration of the technology, and made this short video.

The research being conducted here is part of an implementation project based on Kwon’s original study, the results of which can be found in this research report and its accompanying two-page technical summary from MnDOT Research Services.