摘要
The purposes of this paper are to better understand the design and impact of left turn lane offset and provide state transportation agencies recommendations on best practices and alternative design options to address left turn sight line obstruction issues.Research studies and existing guidelines on left turn lane offset were reviewed and summarized to offer insights in driver sight distance and behavior,intersection safety and operations,as well as design elements related to left turn lane offset.Studies showed that at both unsignalized intersections and signalized intersections with permitted left turns,obstructed sight line could cause higher possibilities of collisions between left turning vehicles and oncoming vehicles from the opposing direction.Existing evaluations of left turn lane offset,with data from multiple states in the United States,reported that positive left turn lane offsets were beneficial in terms of safety and operations.Most agency guidelines provided very limited discussions about left turn lane offset.This review demonstrated that positive left turn lane offsets are beneficial to intersection safety and operations.Based on the review of research and guidelines,recommendations were provided for transportation agencies for left turn lane offset implementation.A discussion on new left turn design concepts was also included to point out directions for future research and practice.
基金
the Local Road Research Board in the Minnesota Department of Transportation,Office of Research&Innovation,for sponsoring this study(contract No.1003328(WO)1)
作者简介
Corresponding author:Yu Song,Tel.:+18604865400.E-mail addresses:fred.song@uconn.edu(Y.Song),Dr.,is a postdoctoral research associate at the Connecticut Transportation Institute.He graduated from the University of Wisconsin-Madison where he earned his doctoral degree in civil and environmental engineering.Dr.Song's research covers areas of transportation safety,operations,design,and user behavior;Madhav V.Chitturi,Dr.,is an assistant research scientist at the Traffic Operations and Safety Laboratory,Department of Civil and Environmental Engineering,University of Wisconsin-Madison.Dr.Chitturi has published over 50 articles in peer-reviewed journals,one book,and 50 articles in peerreviewed conferences.Dr.Chitturi has over 19 years of research experience on multiple aspects of traffic operations and safety including work zones,signal operations,winter maintenance,intelligent transportation systems,roundabouts,older driver safety,intersection safety,work zone safety,Bluetooth applications in transportation,human factors in crashes and incident management,E-mail addresses:mchitturi@wisc.edu(M.V.Chitturi);William F.Bremer,has been a part-time senior transportation civil engineer at the Traffic Operations and Safety Laboratory,University of Wisconsin-Madison for the past seven years.He graduated from the University of Wisconsin-Platteville with a BS degree in civil engineering in 1970.He retired in 2012 after 35 years serving as a highway safety engineer with the Federal Highway Administration in the Wisconsin Division.He is a member of the Institute of Transportation Engineers,E-mail addresses:wbremer@wisc.edu(W.F.Bremer);Andrea R.Bill,is currently the traffic safety engineering research program manager at the Traffic Operations and Safety Laboratory and program director with engineering professional development at the University of Wisconsin-Madison.Her current research incorporates aspects from traffic operations and traffic safety,with a specific emphasis on discovering new and innovative ways to address traffic crashes,E-mail addresses:bill@wisc.edu(A.R.Bill);David A.Noyce,Dr.,is the executive associate dean at the College of Engineering,Authur F.Hawnn professor of transportation engineering at the Department of Civil and Environmental Engineering,and the director of the Traffic Operations and Safety Laboratory,University of Wisconsin-Madison.Dr.Noyce has over 35 years of experience in transportation engineering and has authored more than 200 academic publications.Dr.Noyce serves leadership and membership roles in multiple academic and professional organizations including American Society of Civil Engineers,Institute of Transportation Engineers,Transportation Research Board,and the National Committee on Uniform Traffic Control Devices,E-mail addresses:danoyce@wisc.edu(D.A.Noyce)
