PSI - Issue 78

Amirmahmoud Behzadi et al. / Procedia Structural Integrity 78 (2026) 513–520

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2. Descriptive Statistics Using WIM data collected from a provincial road, this study analyzed key parameters such as gross vehicle mass, length, axle configuration, and inter-vehicle distance. Data cleaning was then performed to remove outliers such as records with zero weight or too long vehicle lengths. According to the WIM data, all vehicles were classified into 12 categories based on axle count and arrangement as illustrated in Table 1. Probabilistic distributions were derived for each category using Gaussian mixture models (for mass and length) and exponential distributions (for inter-vehicle spacing). As an example, Fig. 2 demonstrates the resulting histogram and PDFs for vehicles belonging to Cat. F (Table 1), where Fig. 2a and 2b plot the histogram and the PDF of gross weight and vehicle length for Cat. F respectively, a Gaussian Mixture Distribution ( GMD ) is fitted to both histograms, as well as inter-vehicle distance for all collected traffic data (Fig. 2c). Outlier filtering was applied to ensure data integrity. Braking deceleration data were obtained from the 100-Car Naturalistic Driving Study (2006) (for light vehicles) and Martins et al. (2015) (for heavy vehicles). Maximum deceleration distributions were generated using fitted Gaussian mixtures. A threshold of 4 m/s² was adopted to define hard braking events. Using the Monte Carlo simulation, for each span length, convoy configurations are simulated with an increasing number of vehicles (light and heavy), starting from a single vehicle. Initially, for each traffic scenario, the vehicle category is randomly sampled by using the Monte Carlo simulation according to the classification reported in Table 1. Once the vehicle category is defined, mass, length, inter-vehicle distance, and deceleration are generated from the corresponding PDFs and assigned to the corresponding vehicle. a b

c

Fig. 2. Histogram and PDF of (a) vehicle gross mass, (b) vehicle length, and (c) inter-vehicle distance.