Evaluation of Weigh-in-Motion Systems

About the report:

The objective of this research was to evaluate low cost weigh-in-motion systems. The three systems evaluated were (1) a capacitance weigh mat system, (2) a bridge weighing system, and (3) a piezoelectric cable sensor system. All three systems have a two-lane capability. An evaluation was made of (1) the quality of the data, (2) the performance of the equipment, (3) the applications of the equipment and its ease of use, and (4) the format of the data and its usefulness. Although objective data were used when possible, the majority of the evaluation is subjective. The quality of the data from each of the three systems is about the same. The piezoelectric cable system provides slightly lower quality data than the other two systems. The equipment of the capacitance weigh mat performed well; that of the bridge system was adequate; and there was concern about the durability of the piezoelectric cable system. Because of the tradeoffs between the capacitance weigh mat system and the bridge system, it is difficult to rank them. The piezoelectric cable system's sensors are permanently installed; therefore, it is not as portable as the other two systems. With regard to the format of the data and its usefulness (which are dependent mostly on the software and not the sensors), the capacitance weigh mat system is flexible and provides individual truck records in two formats, the bridge system provides the most comprehensive tables, and the piezoelectric cable system is limited and depends on other software to generate additional tables. Suggestions are made about how to use the systems and how to improve their performance.

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