This study examined current freeway entry ramp design speed criteria by undertaking field observations of entry ramp traffic operations and by conducting analyses attempting to identify relationships between vehicle speed and geometric features. Three specific recommendations were developed: (1) The AASHTO acceleration rate model used to estimate acceleration lane lengths should not be changed; (2) The design criterion defining a ramp's design speed as 50 percent of the freeway design speed should be deleted from AASHTO and TxDOT policy; (3) Acceleration lengths for taper-type entry ramps should include only the lane portions from which ramp drivers can clearly view the freeway right lane traffic. The AASHTO acceleration length model should be clarified to include this specification.


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    Title :

    Reevaluation of Ramp Design Speed Criteria: Summary Report


    Contributors:
    M. Hunter (author) / R. B. Machemehl (author) / A. Tsyganov (author)

    Publication date :

    2000


    Size :

    28 pages


    Type of media :

    Report


    Type of material :

    No indication


    Language :

    English




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