The intersection sight distance (ISD) design presented by AASHTO is based on extreme values of the component design variables such as design speed, perception–reaction time (a high percentile), and friction coefficient (a low percentile). A reliability method is presented, based on AASHTO, that does not rely on extreme values but instead considers the moments (mean and variance) of the probability distribution of each random variable. The method also accounts for correlations among the component random variables. In Cases I and II of AASHTO, the variations of the sight distance along both legs of the intersection are considered for both design and evaluation. For evaluation (involving an exiting obstruction), these variations are combined into a single variable that determines whether the corresponding sight line is obstructed. In Case III, only the sight distance leg along the major road has variations. The proposed method is straightforward and involves simple, closed-form mathematics for calculating sight distance and associated reliability. Sensitivity of ISD to various design variables is examined. ISD reliability-based values for various cases are presented from data reported in the literature, and results are compared with current AASHTO design values.


    Access

    Download

    Check availability in my library

    Order at Subito €


    Export, share and cite



    Title :

    Reliability Approach to Intersection Sight Distance Design


    Additional title:

    Transportation Research Record: Journal of the Transportation Research Board


    Contributors:


    Publication date :

    2000-01-01




    Type of media :

    Article (Journal)


    Type of material :

    Electronic Resource


    Language :

    English




    Intersection sight distance analysis and guidelines

    Awadallah, Faisal | Online Contents | 2009


    Intersection sight distance analysis and guidelines

    Awadallah, Faisal | Online Contents | 2009


    Three-Dimensional Stop-Control Intersection Sight Distance

    Easa, Said M. / Ali, Zain A. | Transportation Research Record | 2006