OPERATING SPEED BASED ALIGNMENT CONSISTENCY EVALUATION USING DRIVING SIMULATOR: CASE STUDIES FROM TAIGAN FREEWAY IN JIANGXI, CHINA

摘要

Geometric design consistency refers to the conformance of a proposed or existing freeway's geometry with the driver's expectancy. Considerable efforts have been undertaken to develop potential quantitative consistency measures and models to estimate them. However, little work has been focused on the facts of freeways in China, especially in mountainous areas. The primary objective of this study is to examine and quantify the design consistency of a freeway, using an interactive driving simulator, so as to identify any inconsistency on the roadway geometry and improve its overall safety performance. More specifically, the techniques to evaluate the consistency of a geometric design depend on three criteria: design consistency, operating speed consistency, and consistency in driving dynamics, as well as three levels of consistency: good, acceptable and poor. In the case of Taigan Freeway, a part of G45 Daguang Freeway in Jiangxi, China, a 21km long segment has been divided into 38 sections including 22 curves and 16 tangents, and transferred into the graphics models in the simulator system. There were 42 drivers required to take part in the simulation experiment and the speed, location of vehicle, and other real time data were recorded as well. The findings have shown that these proposed measures and standards can identify a geometric inconsistency more effectively when there is a large rate of change in the alignment elements for a successive roadway segment.%线形设计一致性指一条规划或运营的高速公路线形与驾驶员期望相吻合，已有的研究中大量关注了可用于设计一致性评价的量化指标及模型等，但对中国高速公路的情况却研究不多，尤其是山区高速公路。本研究的主要目的在于通过交互式驾驶模拟器实验,测定一条高速公路的线形设计一致性，以便于识别路线上任何线形不一致的区段、提高其整体安全绩效。为此，确定了线形设计一致性评价的3个准则：设计一致性、运行速度一致性、车辆运动一致性，以及一致性水平划分：好、可接受、差。选取泰赣高速即大广高速G45江西段的—21公里路段进行模拟实验，将全线划分为38个小区段，包括22个曲线段和16个直线段，并转化为模拟器系统中的图像模型。42个驾驶员参与了在模拟环境中进行驾驶操作，车速、车辆位置及其它实时交通信息被记录在系统中。研究结果表明当连续路段的线形元素出现突变时，所建议的一致性判别指标及标准能有效识别其位置。