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原文传递 Design Guidelines for Horizontal Sightline Offsets

题名：	Design Guidelines for Horizontal Sightline Offsets
责任者：	National Academies of Sciences, Engineering, and Medicine; Transportation Research Board; National Cooperative Highway Research Program; National Cooperative Highway Research Program Synthesis Program; Synthesis Program; Ingrid B. Potts, Douglas W. Harwood, Daniel J. Cook, Eric T. Donnell, and Bachir Hamadeh
关键词：	Transportation and Infrastructure — Design Transportation and Infrastructure — Highways Transportation and Infrastructure — Safety and Human Factors
学科分类：	暂无分类
摘要：	The distance between the driver’s line of sight along the roadway ahead on a horizontal curve and a sight obstruction on the inside of the curve is known as the horizontal sightline offset (HSO). Highway agencies can use NCHRP Research Report 910: Design Guidelines for Horizontal Sightline Offsets as guidance to address the types of sight distance restrictions that are most likely to be encountered on specific roadway types. The relationship between stopping sight distance (SSD) and the frequency and severity of crashes has been difficult to quantify because the role of SSD in reducing crashes is highly situational. The design criteria for the horizontal component of SSD in what is known as AASHTO's Green Book are based on the maximum sightline offset that may be needed at any point along a curve with a given radius, which doesn't cover all possible situations. Designers compensate for the limitations on driver sight distance in various ways, including: accepting shorter sightlines, lowering design speed, increasing shoulder width, or providing additional signage. There are advantages and disadvantages to the trade-offs; as a result, many highway agencies have used the design exception process to address the trade-offs for sight distance in such situations. This project conducted research to evaluate these situations and determine what criteria or mitigation will provide acceptable solutions when impaired horizontal sightline offsets are encountered. The project includes a tool (an Excel spreadsheet) that may be used to calculate sight distance.
出版机构：	Transportation Research Board
提交日期：	2019
报告类型：	科技报告
资源类型：	科技（咨询、行业）报告
初始创建时间：	2019