Chen Hongyun, Fabregas Aldo, Lin Pei-Sung
Embry-Riddle Aeronautical University, 600 S. Clyde Morris Blvd., Daytona Beach, FL 32124, United States.
Florida Institute of Technology, Melbourne, FL 32901, United States.
Accid Anal Prev. 2016 May;90:63-72. doi: 10.1016/j.aap.2016.02.006. Epub 2016 Feb 27.
Well-planted and maintained landscaping can help reduce driving stress, provide better visual quality, and decrease over speeding, thus improving roadway safety. Florida Department of Transportation (FDOT) Standard Index (SI-546) is one of the more demanding standards in the U.S. for landscaping design criteria at highway medians near intersections. The purposes of this study were to (1) empirically evaluate the safety results of SI-546 at unsignalized intersections and (2) quantify the impacts of geometrics, traffic, and landscaping design features on total crashes and injury plus fatal crashes. The studied unsignalized intersections were divided into (1) those without median trees near intersections, (2) those with median trees near intersections that were compliant with SI-546, and (3) those with median trees near intersections that were non-compliant with SI-546. A total of 72 intersections were selected, for which five-year crash data from 2006-2010 were collected. The sites that were compliant with SI-546 showed the best safety performance in terms of the lowest crash counts and crash rates. Four crash predictive models-two for total crashes and two for injury crashes-were developed. The results indicated that improperly planted and maintained median trees near highway intersections can increase the total number of crashes and injury plus fatal crashes at a 90% confidence level; no significant difference could be found in crash rates between sites that were compliant with SI-546 and sites without trees. All other conditions remaining the same, an intersection with trees that was not compliant with SI-546 had 63% more crashes and almost doubled injury plus fatal crashes than those at intersections without trees. The study indicates that appropriate landscaping in highway medians near intersections can be an engineering technology that not only improves roadway environmental quality but also maintains intersection safety.
精心种植和维护的景观美化可以帮助减轻驾驶压力，提供更好的视觉质量，并减少超速行驶，从而提高道路安全性。佛罗里达州交通部（FDOT）标准指数（SI - 546）是美国对交叉路口附近公路中央分隔带景观设计标准要求较高的标准之一。本研究的目的是：（1）实证评估SI - 546在无信号控制交叉路口的安全效果；（2）量化几何形状、交通和景观设计特征对总碰撞事故以及受伤和致命碰撞事故的影响。所研究的无信号控制交叉路口分为：（1）交叉路口附近中央分隔带没有树木的；（2）交叉路口附近中央分隔带有符合SI - 546的树木的；（3）交叉路口附近中央分隔带有不符合SI - 546的树木的。总共选择了72个交叉路口，并收集了2006年至2010年的五年碰撞事故数据。符合SI - 546的地点在碰撞事故数量和碰撞事故率方面表现出最佳的安全性能。开发了四个碰撞预测模型——两个用于总碰撞事故，两个用于受伤碰撞事故。结果表明，在公路交叉路口附近种植和维护不当的中央分隔带树木在90%的置信水平下会增加碰撞事故总数以及受伤和致命碰撞事故的数量；符合SI - 546的地点和没有树木的地点之间的碰撞事故率没有显著差异。在所有其他条件相同的情况下，中央分隔带有不符合SI - 546的树木的交叉路口比没有树木的交叉路口碰撞事故多63%，受伤和致命碰撞事故几乎增加了一倍。该研究表明，交叉路口附近公路中央分隔带进行适当的景观美化不仅可以改善道路环境质量，还能维护交叉路口的安全，是一种工程技术。
