Beijing Engineering Research Center of Urban Transport Operation Guarantee, College of Metropolitan Transportation, Beijing University of Technology, No. 100 Pingleyuan, Chaoyang District, Beijing 100124, PR China.
Research Institute of Highway Ministry of Transport, No. 8 Xitucheng Road, Handian District, Beijing 100088, PR China.
Accid Anal Prev. 2018 Jun;115:41-52. doi: 10.1016/j.aap.2018.02.027. Epub 2018 Mar 13.
Longitudinal speed reduction markings (LSRMs) are designed to alert drivers to an upcoming change in roadway geometry (e.g. direct connectors with smaller radii). In Beijing, LSRMs are usually installed on direct connectors of urban expressways. The objective of this paper is to examine the influence of LSRMs on vehicle operation and driver behavior, and evaluate the decelerating effectiveness of LSRMs on direct connectors with different radii. Empirical data were collected in a driving simulator, and indicators representing vehicle operation status and driving behavior were proposed. To examine the influence of LSRMs, an analysis segment was defined, which begins 500 m prior to the entering point of the connector and ends at the exiting point of the connector. Furthermore, the analysis segment was evenly divided into a series of subsections; the length of each subsection is 50 m. This definition is introduced based on the assumption that drivers would decelerate smoothly in advance of the connector. The analysis results show that drivers tend to decelerate earlier when the radii were 200 m or 300 m. When approaching the connector, drivers tend to decelerate at 500 m thru 250 m in advance of the connector with a 200 m radius; deceleration happens at 300 m-0 m in advance of the connector with a 300 m radius. On the connector, drivers controlled the throttle pedal use at 100 thru 300 m after the entering point when the radius was 200 m; deceleration occurred in two regions when the radius was 300 m: 0 m-900 m from the entering point, and the last 1,000 m of the connector. The analytical results further revealed that LSRMs would be effective at reducing speeds when the radius of the direct connector was 300 m.
纵向减速标线（LSRM）旨在提醒驾驶员即将发生路面几何形状的变化（例如，半径较小的直接连接）。在北京，LSRM 通常安装在城市高速公路的直接连接上。本文的目的是研究 LSRM 对车辆运行和驾驶员行为的影响，并评估不同半径的直接连接上 LSRM 的减速效果。在驾驶模拟器中收集了实证数据，并提出了代表车辆运行状态和驾驶行为的指标。为了研究 LSRM 的影响，定义了一个分析段，该分析段从连接点的进入点前 500 米开始，结束于连接点的出口点。此外，将分析段均匀地划分为一系列小节；每个小节的长度为 50 米。这一定义是基于驾驶员在连接点前平稳减速的假设提出的。分析结果表明，当半径为 200 米或 300 米时，驾驶员往往会更早减速。当接近连接点时，驾驶员往往会在半径为 200 米的连接点前 500 米至 250 米处提前减速；在半径为 300 米的连接点前 300 米至 0 米处减速。在连接点上，当半径为 200 米时，驾驶员在进入点后 100 米至 300 米处控制油门踏板使用；当半径为 300 米时，在连接点上发生了两次减速：从进入点到 900 米，以及连接点的最后 1000 米。分析结果进一步表明，当直接连接的半径为 300 米时，LSRM 将有效降低速度。
