Geometric models to calculate intersection sight distance for unprotected left-turn traffic

    Authors

    X. D. Yan; E. Radwan;Trb

    Comments

    Authors: contact us about adding a copy of your work at STARS@ucf.edu

    Keywords

    Engineering, Civil; Transportation Science & Technology

    Abstract

    At signalized intersections with opposing left-turn lanes, inadequate sight distance of left-turn drivers caused by obstructions from opposing left-turn vehicles can not only contribute to a serious safety problem due to drivers misjudging the gaps in the opposing through traffic but also cause increased intersection delay. This delay is created because drivers need more time to make sure that the opposing through lanes are clear. The 2001 AASHTO manual pointed out that the typical poor visibility of opposing through traffic usually occurs at signal intersections with medians wider than 18 ft and recommended two improvement methods: creating parallel offset left-turn lanes and tapered offset left-turn lanes. However, AASHTO did not provide the specific design guideline, nor did it present the related geometric design model. Sight-distance geometric models for unprotected left-turning vehicles from the major road onto the minor road at signalized intersections and vision improvement effects of the two offset methods were developed, and the relationship between available sight distance and related intersection geometric parameters was analyzed.

    Journal Title

    Geometric Design and the Effects on Traffic Operations 2004

    Issue/Number

    1881

    Publication Date

    1-1-2004

    Document Type

    Article

    Language

    English

    First Page

    46

    Last Page

    53

    WOS Identifier

    WOS:000227333400006

    ISSN

    0361-1981; 0-309-09477-1

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