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Estimating mountainous freeway crash rate: Application of a spatial model with three-dimensional (3D) alignment
Jie Wang1, Shijian He2, Xiaoqi Zhai3
1School of Traffic and Transportation Engineering, Changsha University of Science and Technology, Changsha 410114, China; Key Laboratory of Highway Engineering of Ministry of Education, Changsha University of Science and Technology, Changsha 410114, China.
Accident; Analysis and Prevention
|March 28, 2022
Summary
This study reveals that three-dimensional (3D) road alignment significantly impacts traffic safety on mountainous freeways. Analyzing 3D curvature and torsion with a Bayesian spatial Tobit model improves crash rate prediction.
Area of Science:
- Road safety engineering
- Transportation engineering
- Geometrics and design
Background:
- Road alignment is a complex 3D curve, influencing traffic safety.
- Traditional safety models often overlook the 3D nature of road geometry.
- Mountainous freeways present unique safety challenges due to their intricate alignments.
Purpose of the Study:
- To quantitatively assess the impact of 3D road alignment on traffic safety in mountainous freeways.
- To develop and validate a statistical model for predicting crash rates considering 3D road geometry.
- To investigate the role of spatial correlation in freeway crash data.
Main Methods:
- Derivation of 3D curvature and torsion parameters to characterize road curves.
- Classification of 3D road alignments into twelve combined types.
- Development of the Bayesian spatial Tobit (BST) model for crash statistical analysis.
- Comparison with the Bayesian Tobit (BT) model using real-world crash data.
Main Results:
- The BST model demonstrated superior goodness-of-fit compared to the BT model.
- Differences in 3D curvature and torsion between adjacent segments significantly affect crash rates.
- The BST model provides reliable predictions for freeway crash rates across different alignments.
Conclusions:
- Three-dimensional road alignment parameters are crucial for accurate mountainous freeway crash rate estimation.
- The BST model effectively captures spatial correlations in crash data.
- This research offers valuable insights into road geometric design and traffic safety modeling.
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