Safety Evaluation of Adjacent Combined Alignments of Mountain Freeway

Abstract:

In this paper, the driving simulator was used to realize the roadway scenario for Yongji freeway in Hunan Province, China. The driving scene was reproduced in virtual reality by the exact road design parameters and roadside elements from the design blueprint. The research objects are tangent + horizontal curve combined alignment and continuous horizontal curves combined alignment. The safety evaluation method was introduced based on the driving simulation data in terms of experimental design, data processing, indicator selection and model building. The results indicate that speed differential is positive correlated to the length of tangent segment and operating speed in the model of tangent + horizontal curve combined alignment, and it is also positive correlated to the length of the first horizontal curve and the ratio of curvature radius in the model of continuous horizontal curves combined alignment. The 50th/85th percentile values of the speed differentials are found as the safety thresholds of “GOOD”, “FAIR” and “POOR” according to their distribution.