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                Safety of U-Turns at Unsignalized Median Openings: Some Research Findings
Publication Information
              Publication External Link:Link not available
              Publication Type:Article
                      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 openingsa 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.





Levinson, H.S., I.B. Potts, D.W. Harwood, J. Gluck, and D.J. Torbic. Safety of U-Turns at Unsignalized Median Openings: Some Research Findings. In Transportation Research Record: Journal of the Transportation Research Board, No. 1912. Transportation Research Board, National Research Council, Washington, D.C., 2005, pp. 72-81
              Publishing Date:January 2005
                                                  FHWA Program(s):Research
              Safety
              AMRP Program(s):Safety Data and Analysis
              FHWA Activities:Highway Safety Information System
              Subject Area:Safety and Human Factors U.S. DEPARTMENT OF TRANSPORTATION

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