多车道高速公路出口开口段安全特性分析

为研究不同断面形式下的多车道高速公路出口影响区开口长度及流量与交通安全的关系，针对2种断面形式的高速公路出口，分别设计了3种不同的开口长度，结合3种不同流量条件设计了18个不同的驾驶模拟场景。实验招募30名被试者开展模拟驾驶实验，提取不同开口长度及流量条件下各断面形式高速公路出口的车辆行驶轨迹、换道间隙的选择、减速度、最小 TTC (Time to Collision)等驾驶行为特性参数，综合分析基于驾驶行为数据对不同开口长度的行车风险。结果表明：两种断面形式下，开口长度对于车辆在开口段上的换道点选择存在显著影响；两种断面形式下，1500 m的开口长度能够满足绝大多数驾驶人的换道需求；在换道间隙选择中，大都集中在5~6 s，分离式断面下的开口长度对于低于临界间隙的换道间隙出现的频次具有显著影响；流量及开口长度对于最大减速度及TTC最小值和分布位置均不存在显著性影响，但分离式断面下的最大减速度和最小TTC相较于整体式断面更小；此外，整体式断面中内侧3车道的行车风险低于分离式断面，分离式断面中外侧车道的行车风险低于整体式断面。

Safety Characteristics of Exit Section of Multi-lane Expressway

This paper investigated the relationship between traffic safety and the factors of exit opening length and traffic flow rate on the multi-lane expressway. Three different opening lengths were designed for two types of expressway exits and three different traffic flow conditions. 18 driving simulation scenarios were designed and the experiment was performed with 30 subjects for driving simulations. The driving behavior parameters that collected in the experiment included driving trajectory, deceleration, lane change gap, and other driving behaviors of the expressway exit. Then, a comprehensive evaluation of the driving risks was performed for different traffic sign design schemes. The results indicate that the exit opening length has a significant impact on the choice of lane changing points on the opening section under two cross- sectional scenarios. The opening length of 1500 meters would meet the lane changing needs of most drivers. The most common choice of lane changing gap ranging from 5 to 6 seconds. The length of the opening under the separated section has a significant impact on the frequency of the lane changing gap below the critical gap. The flow rate and opening length have no significant influence on the maximum deceleration, the minimum TTC and the distribution position, but the maximum deceleration rate and minimum TTC of the separated section are smaller than those of the monolithic section. In addition, the driving risk of the inner three lanes in the monolithic section is lower than the driving risk of the inner three lanes in the separated section; while the driving risk of the outer lane in the separated section is lower than that of the monolithic section.