Investigating Factors Influencing Crash Severity on Mountainous Two-Lane Roads: Machine Learning Versus Statistical Models

Ziyuan Qi, Jingmeng Yao, Xuan Zou, Kairui Pu, Wenwen Qin and Wu Li ()
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Ziyuan Qi: Faculty of Transportation Engineering, Kunming University of Science and Technology, Kunming 650500, China
Jingmeng Yao: Faculty of Transportation Engineering, Kunming University of Science and Technology, Kunming 650500, China
Xuan Zou: Faculty of Transportation Engineering, Kunming University of Science and Technology, Kunming 650500, China
Kairui Pu: Faculty of Transportation Engineering, Kunming University of Science and Technology, Kunming 650500, China
Wenwen Qin: Faculty of Transportation Engineering, Kunming University of Science and Technology, Kunming 650500, China
Wu Li: Faculty of Transportation Engineering, Kunming University of Science and Technology, Kunming 650500, China

Sustainability, 2024, vol. 16, issue 18, 1-27

Abstract: Due to poor road design, challenging terrain, and difficult geological conditions, traffic accidents on mountainous two-lane roads are more frequent and severe. This study aims to address the lack of understanding of key factors affecting accident severity with the goal of improving mountainous traffic safety, thereby contributing to sustainable transportation systems. The focus of this study is to compare the interpretability of model performances with three statistical models (Ordered Logit, Partial Proportional Odds Model, and Multinomial Logit) and six machine learning models (Decision Tree, Random Forest, Gradient Boosting, Extra Trees, AdaBoost, and XGBoost) on two-lane mountain roads in Yunnan Province, China. Additionally, we assessed the ability of these models to uncover underlying causal relationships, particularly how accident causes affect severity. Using the SHapley Additive exPlanations (SHAP) method, we interpreted the influence of risk factors in the machine learning models. Our findings indicate that machine learning models, especially XGBoost, outperform statistical models in predicting accident severity. The results highlight that accident patterns are the most significant determinants of severity, followed by road-related factors and the type of colliding vehicles. Environmental factors like weather, however, have minimal impact. Notably, vehicle falling, head-on collisions, and longitudinal slope sections are linked to more severe accidents, while minor accidents are more frequent on horizontal curve sections and areas that combine curves and slopes. These insights can help traffic management agencies develop targeted measures to reduce accident rates and enhance road safety, which is critical for promoting sustainable transportation in mountainous regions.

Keywords: traffic safety; mountainous two-lane roads; machine learning; statistical model; SHAP; sustainable transportation (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2024
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (2)

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