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                NCHRP Report 524: Safety of U-Turns at Unsignalized Median Openings
Publication Information
              Publication External Link:NCHRP Report 524: Safety of U-Turns at Unsignalized Median Openings
                          Abstract:Many state and local transportation agencies install nontraversable medians on multilane arterials to improve safety and travel times and to better manage local access. Because 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. NCHRP Project 17-21, Safety of U-Turns at Unsignalized Median Openings, was conducted to further assess the safety effects of U-turn volumes. This paper presents key findings, along with the access management applications, from that research. It includes a summary of key literature, presents a detailed classification scheme for median openings, summarizes the results of comprehensive field studies, and identifies several highway planning implications.

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 very 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. Based on these limited accident frequencies, there is no indication that U-turns at unsignalized median openings constitute a major safety concern.
              Publishing Date:January 2004
                                      Author(s):Harwood,
    
          Douglas
                      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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