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Title: Safety of U-Turns at Unsignalized Median Openings: Some Research Findings
Accession Number: 01005367
Record Type: Component
Record URL: Availability: Transportation Research Board Business Office 500 Fifth Street, NW Find a library where document is available Abstract: Many state and local transportation agencies install nontraversable medians on multilane highways to improve safety and travel times and to manage local access better. While nontraversable medians restrict direct left-turn access to and from adjacent developments, traffic destined for these locations must use alternate routes, some of which may involve making U-turns at nearby median openings—a movement often referred to as an indirect left turn. Until recently, the safety effects of increased U-turn volumes have been largely unknown. NCHRP Project 17-21, Safety of U-Turns at Unsignalized Median Openings, documented the safety performance and operational effects of U-turns at median openings. This paper presents the key findings from that research. It presents a summary of key literature and current highway agency practice related to median openings, a detailed classification scheme for median openings, and a summary of the results of comprehensive field studies. The research results indicate that access management strategies that increase U-turn volumes at unsignalized median openings can be used safely and effectively. Analysis of accident data found that accidents related to U-turn and left-turn maneuvers at unsignalized median openings occur infrequently. In urban arterial corridors, unsignalized median openings experienced an average of 0.41 U-turn-plus-left-turn accidents per median opening per year. In rural arterial corridors, unsignalized median openings experienced an average of 0.20 U-turn-plus-left-turn accidents per median opening per year. On the basis of these limited accident frequencies, there is no indication that U-turns at unsignalized median openings are a major safety concern.
Monograph Title: Monograph Accession #: 01005363
Language: English
Authors: Levinson, Herbert SPotts, Ingrid BHarwood, Douglas WGluck, JeromeTorbic, Darren JohnPagination: pp 72-81
Publication Date: 2005
ISBN: 0309093856
Media Type: Print
Features: Figures
(1)
; References
(18)
; Tables
(8)
TRT Terms: Uncontrolled Terms: Subject Areas: Design; Highways; Safety and Human Factors; I20: Design and Planning of Transport Infrastructure; I81: Accident Statistics
Files: TRIS, TRB, ATRI
Created Date: Oct 11 2005 11:36AM
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