Adverse weather conditions are a critical external factor that threaten traffic safety on freeways. Variable speed limit (VSL) operations can be used as a traffic management tool to harmonize vehicle speed and reduce the likelihood of crashes during adverse weather conditions. This paper proposes a novel VSL operations strategy based on the prediction of weather and traffic conditions, referred to as a proactive VSL operations strategy. The k–nearest neighbors ( k-NN) statistic was used to predict weather and traffic conditions. VSL operations logic, which used visibility distances and safe stopping distances obtained from road weather information systems and average speeds obtained by vehicle detection systems, was developed. The proposed methodology is focused on the restricted visibility distance resulting from foggy weather conditions on freeways. A microscopic traffic simulator, VISSIM, was used to simulate a freeway traffic stream and collect vehicle-maneuvering data. An external application program interface, the VISSIM COM interface, was used to implement the proposed VSL operations strategy. A surrogate safety assessment model was used to derive indirect safety measures to evaluate the effectiveness of the proposed methodology. Total conflicts in the proposed VSL algorithm were reduced in comparison with a system lacking VSL by 19.10% and 27.27% under moderately and severely foggy weather conditions, respectively. These outcomes are expected to be of great use in the development of more effective VSL systems to enhance freeway safety during adverse weather conditions.


    Access

    Download

    Check availability in my library

    Order at Subito €


    Export, share and cite



    Title :

    Proactive Strategy for Variable Speed Limit Operations on Freeways Under Foggy Weather Conditions


    Additional title:

    Transportation Research Record: Journal of the Transportation Research Board


    Contributors:
    Choi, Saerona (author) / Oh, Cheol (author)


    Publication date :

    2016-01-01




    Type of media :

    Article (Journal)


    Type of material :

    Electronic Resource


    Language :

    English



    Control Method of Variable Speed Limits for Freeways under Foggy Weather Conditions

    Zhang, Shan / Zhang, Cunbao / Peng, Hanhui et al. | ASCE | 2018


    Real-Time Traffic Safety Evaluation Model for Freeways in Foggy Conditions

    Wang, Rong / Gu, Yuanli / Huang, Entan | ASCE | 2019




    Safe Spacing Research Based on the Theory of Cellular Automation on Freeways in Foggy Weather

    Shi, Q. / Huang, Z. / Liu, W. | British Library Conference Proceedings | 2009