The Effect of Flexible Pavement Mechanics on the Accuracy of Axle Load Sensors in Vehicle Weigh-in-Motion Systems

Abstract

Weigh-in-Motion systems are tools to prevent road pavements from the adverse phenomena of vehicle overloading. However, the effectiveness of these systems can be significantly increased by improving weighing accuracy, which is now insufficient for direct enforcement of overloaded vehicles. Field tests show that the accuracy of Weigh-in-Motion axle load sensors installed in the flexible (asphalt) pavements depends on pavement temperature and vehicle speeds. Although this is a known phenomenon, it has not been explained yet. The aim of our study is to fill this gap in the knowledge. The explanation of this phenomena which is presented in the paper is based on pavement/sensors mechanics and the application of the multilayer elastic half-space theory. We show that differences in the distribution of vertical and horizontal stresses in the pavement structure are the cause of vehicle weight measurement errors. These studies are important in terms of Weigh-in-Motion systems for direct enforcement and will help to improve the weighing results accuracy.

Detection of Moving Load on Pavement Using Piezoelectric Sensors

“…This makes the WIM method superior to the static weighing method with time-saving and higher traffic efficiency. Given the above advantages, the WIM system has been widely studied and developed in recent years [3][4][5][6][7][8]. However, the WIM method encounters various shortcomings, e.g., high costs for installation and maintenance, and low accuracy of measurements [2].…”

Optimised Autocalibration Algorithm of Weigh-In-Motion Systems for Direct Mass Enforcement

“…However, due to a variety of interfering factors [15][16][17], the weighing error in WIM systems can amount to from 5% to 10% and, what is worse, this can change while the system is in operation [18]. We have written about this topic previously, demonstrating that the main causes of the instability of the system are changes in pavement temperature and the speed of the weighed vehicle [17]. The low precision of weighing and its variability mean that WIM systems cannot be used for direct mass enforcement.…”

“…The climate conditions in which WIM systems operate are subject to change both on a daily scale and over the course of the seasons [19][20][21]. We discovered that the factors which most impact the precision of weighing in WIM systems are pavement quality and temperature, vehicle speed, wind speed and direction, and the state of the vehicle's suspension [16,17,22]. The subject of previous research of the authors was primarily the influence of temperature and speed.…”

“…Sensitivity of these sensors to the change of speed of the weighed vehicle is different. For polymer sensors, a speed change in the range from 50 km/h to 90 km/h changes the weighing result by ~10%, for quartz sensors by ~4%-5% and for bending plate sensors by ~2% [17,23]. Studies on the impact of wind direction and power are at an early stage and do not yet allow drawing reliable conclusions.…”

Feasibility Study for Using Piezoelectric-Based Weigh-In-Motion (WIM) System on Public Roadway

“…Zhang et al provided an optimization framework for the in-pavement WIM system in their study [14]. Burnos and Rys have conducted a comprehensive study to find the weighing accuracy of in-pavement WIM over the pavement/sensor complex behavior [15].…”