Safety effects of the separation distances between driveway exits and downstream U-turn locations.
Safety effects of the separation distances between driveway exits and downstream U-turn locations.
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DOI：
10.1016/j.aap.2007.09.011
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发表时间：
2008-03
期刊：
影响因子：
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通讯作者：
Pan Liu;J. Lu;Hongyun Chen
中科院分区：
文献类型：
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作者：
Pan Liu;J. Lu;Hongyun Chen
使用掉头代替直接左转是一种重要的通道管理方法，已在美国广泛实施，以提高多车道高速公路的安全性。本研究的主要目的是评估车道出口和下游掉头位置之间间隔距离的安全影响。为了实现研究目标，我们对佛罗里达州 140 个街道段报告的事故数据进行了调查。选定的站点根据间隔距离分为三组。进行 t 检验和比例检验来比较不同间隔距离组之间的碰撞频率、碰撞类型和碰撞严重程度。负二项式模型的开发是为了检查导致选定地点报告的事故的因素。数据分析结果表明，间隔距离显着影响车道和下游掉头位置之间街道路段的安全。间隔距离增加 10% 将导致事故总数减少 3.3%，与右转后掉头相关的事故减少 4.5%。模型还表明，在信号交叉口提供掉头将导致在蜿蜒路段发生更多事故。因此，如果要在信号交叉口设置调头，则应提供较长的间隔距离。
Using U-turns as alternatives to direct left-turns is an important access management treatment which has been widely implemented in the United States to improve safety on multilane highways. The primary objective of this study is to evaluate the safety effects of the separation distances between driveway exits and downstream U-turn locations. To achieve the research objective, crash data reported at 140 street segments in the state of Florida were investigated. The selected sites were divided into three groups based on the separation distances. t-Tests and proportionality tests were performed for comparing crash frequency, crash type, and crash severity between different separation distance groups. Negative-binomial models were developed for examining the factors that contribute to the crashes reported at selected sites. The data analysis results show that the separation distances significantly impact the safety of the street segments between driveways and downstream U-turn locations. A 10% increase in separation distance will result in a 3.3% decrease in total crashes and a 4.5% decrease in the crashes which is related with right-turns followed by U-turns. The models also show that providing U-turns at a signalized intersection will result in more crashes at weaving sections. Thus, if U-turns are to be provided at a signalized intersection, a longer separation distance shall be provided.