China Safety Science Journal ›› 2025, Vol. 35 ›› Issue (7): 201-208.doi: 10.16265/j.cnki.issn1003-3033.2025.07.1744

• Public safety • Previous Articles     Next Articles

Comparative analysis of accident severity causation and heterogeneity on low-grade highways in mountainous areas

YAN Jie1(), XING Xiaoliang1,**(), SUN Peng2, ZHANG Yu1, PENG Hanjie3, SUN Tongbo3   

  1. 1 Institute Intelligent Transportation Center, Shandong Transportation Research Institute, Jinan Shandong 250100, China
    2 Engineering Construction Affairs Center, Shandong Provincial Department of Transportation, Jinan Shandong 250002, China
    3 Testing and Calibration Center, Shandong Transportation Research Institute, Jinan Shandong 250100, China
  • Received:2025-03-13 Revised:2025-05-19 Online:2025-08-21 Published:2026-01-28
  • Contact: XING Xiaoliang

Abstract:

In order to explore the heterogeneity sources of the influencing factors of traffic accident severity on low-grade highway and analyze the causal mechanisms of accident severity, based on traffic accident records of a low-grade highway in Chongqing city in the past 7 years, combined with the classification of collision vehicle types, the accident severity inducement analysis model was constructed using the fixed parameter Logit, mixed Logit, and random parameter Logit models considering heterogeneity sources. The differences in goodness-of-fit and heterogeneity of different models were analyzed, and the influence of significant variables on accident severity was quantified using average elasticity coefficient. The results show that the Logit model with random parameters considering heterogeneous sources has the highest goodness-of-fit under the same type of accident conditions. In the comprehensive accident model, the non-motor vehicle of the involved party has the greatest influence on the accident severity. The frontal collision is a heterogeneous variable that obeys a normal distribution of (-0.668, 0.7492). The mean and variance of the parameters are positively influenced by summer and large accident-causing vehicles. The season and involved vehicle types exhibit the largest effect intensity in the vehicle-to-vehicle accident model. The parameters associated with summer, mid-sized accident-causing vehicles, and side collisions follow a one-sided triangular distribution with mean (variance) of 0.586, 0.948, and 0.631, and have mean heterogeneity with the factors of night and horizontal curve radius greater than 1 600 m. The severity of vehicle-to-non-motor vehicle accidents is significantly affected by the variables of non-motor vehicle, night, and frontal collision. The parameters corresponding to the night and involved non-motor vehicle variables obey the unilateral triangular distribution of the mean (variance) 2.040 and 1.330, the mean value of parameters is significantly correlated with the weekend and age over 59 years old. Reasonably segmenting the accident dataset of low-grade highways in mountainous areas helps to reduce the heterogeneity effect in the factors affecting accident severity and improve the accuracy and reliability of accident severity cause analysis results.

Key words: mountainous low-grade highways, accident severity, causality analysis, heterogeneity, Logit model

CLC Number: