Transmission Range Evaluations for Connected Vehicles at Highway-Rail Grade Crossings

Chung-Jen Hsu,Elizabeth G Jones

doi:10.3390/designs1010002

Abstract

This study evaluates the transmission range requirements of Connected Vehicles (CVs) at Highway-Rail Grade Crossings (HRGCs) in terms of safety improvement. The safety improvement of HRGCs is evaluated by using a reliability-based risk analysis that calculates risk of collision for CVs and non-CVs. Trains are assumed to have onboard units that transmit train location and speed information to CVs via vehicle to vehicle communications. The stopping distance and time to collision of a vehicle are the demand functions in reliability-based risk analysis. The demand functions consist of probability density functions of a vehicle’s initial speed, perception-reaction time, initial deceleration rate, final speed, and final deceleration rate. Train arrival time depending on the train speed and transmission range is the supply threshold for calculating the CV’s risk of collision at passive HRGCs. The transmission range’s projected highway distance is the supply threshold for CVs at active HRGCs. After deriving probability density functions of demand functions from the published data, Monte Carlo simulations generate the probabilities or risks that a CV would fail to stop within the transmission range or train arrival time. With the provision of a 600 m transmission range, the risk of collision for the CV is lower than that for the non-CV with a 300 m sight distance to the train at the passive HRGC. The CV’s risk of collision is lower than the non-CV’s with a 300 m transmission range at active HRGCs. The CV application at HRGCs can improve safety by reducing CVs’ risk of collision. A 600 m transmission range is desirable at passive HRGCs. A 300 m transmission is sufficient for CVs at active HRGCs. Overall, a 600 m transmission range is feasible to improve the safety at passive and active HRGCs.

Highlights

Highway-rail grade crossings (HRGCs) are locations with continuing safety issues despite work done to improve their safety
At passive HRGCs, the supply thresholds depend on the train speed, transmission range, sight distance to train, and the angle between the driving direction and vehicle to train direction
The demand function is the same for Connected Vehicles (CVs) and non-CV drivers, different supply thresholds are used in the calculation of risk of collision

Summary

Introduction

Highway-rail grade crossings (HRGCs) are locations with continuing safety issues despite work done to improve their safety. The total number of incidents, injuries, and deaths at public HRGCs in the U.S has declined over the last 10 years; 2060 incidents, 990 injuries, and 237 deaths still occurred in 2015 [1]. These injuries and deaths incur primary (direct, indirect, and intangible) and secondary (supply chain business disruption) costs [2]. Active HRGCs have more incidents, injuries, and deaths than passive HRGCs for they are located in higher traffic areas and more likely to incur incidents [3]. The major cause of incidents at active HRGCs is drivers’ violation of control devices [5]

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