Investigation of Crossing Conflicts by Vehicle Type at Unsignalized T-Intersections under Varying Roadway and Traffic Conditions in India
Publication: Journal of Transportation Engineering, Part A: Systems
Volume 147, Issue 2
Abstract
The study attempts to investigate crossing conflicts at unsignalized T-intersections under mixed traffic conditions using post encroachment time (PET) as a surrogate safety measure (SSM). To comprehend the objective, data for four unsignalized T-intersections with varying intersection geometry (with and without Central Island) was collected using videography techniques. Primarily, PET datasets were extracted in the lab from the recorded video and were checked for their probability distributions. Among all the potential distributions, generalized extreme value (GEV) distribution was observed to be the best-fitted distribution. Further investigations revealed that the percentage of critical crossing conflicts (PCCC) was higher with the presence of motorized two-wheelers (2W) and motorized three-wheelers (3W) in the traffic stream. This was followed by cars, buses, LCVs, and trucks. Among vehicle type combinations (conflicting-offending), 2W-2W, 2W-3W, 3W-2W, and 3W-3W were identified as the most critical cases for the subject study locations. Further, it was observed that the volume of conflicting stream and proportion of 2Ws in the conflicting stream has a significant effect on PCCC. The obtained PCCC, when compared among the subject study locations for similar traffic flow characteristics, revealed a significant difference between them, highlighting the effect of intersection geometry on traffic safety. The severity of conflicts was delineated into four levels by correlating PET values with the speed of conflicting vehicles. The developed severity levels, compared with the field-recorded crash data are found to be in close approximation. This establishes PET as a valid SSM.
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Data Availability Statement
Some or all data, models, or code generated or used during the study are available from the corresponding author by request. Vehicle type-wise PET values for both right-turning conflicts would be made available on request.
Acknowledgments
The authors would like to thank TEQIP-III, a Government of India initiative. The project is sanctioned under the Project No. SVNIT/CED/SSA/TEQIP-III/2975/2019, titled “Proactive Safety Assessment of Un-Signalized T-Intersection under mixed traffic conditions.”
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Published In
Journal of Transportation Engineering, Part A: Systems
Volume 147 • Issue 2 • February 2021
Copyright
© 2020 American Society of Civil Engineers.
History
Received: Nov 27, 2019
Accepted: Sep 1, 2020
Published online: Dec 7, 2020
Published in print: Feb 1, 2021
Discussion open until: May 7, 2021
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