Impact of pavement surface roughness on WIM sensors performance

Abstract

Weigh-in-motion (WIM) systems are vital for collecting accurate and consistent vehicle weight and axle load data, which is essential for highway planning, pavement and bridge design, and freight studies. WIM system accuracy can be influenced by vehicle dynamics, sensor types and layouts, and site-specific factors such as pavement roughness. This study examines the impact of pavement roughness on WIM measurement accuracy using the WIM Roughness Index (WRI), calculated for 24 high-quality WIM sites from the Long-Term Pavement Performance (LTPP) Specific Pavement Studies (SPS) experiment. WRI thresholds, based on AASHTO M331-17 standards, were used to evaluate roughness levels across sites equipped with Quartz Piezo (QP) and Bending Plate (BP) sensors. Results indicate that no significant relationship between WRI and WIM measurement precision or total error based on the available data, suggesting that pavement roughness alone may not be a critical determinant of WIM accuracy. These findings underscore the need for further research to identify alternative factors influencing WIM measurement variability and improve system reliability under diverse road conditions.