It has been empirically observed for years that the queue discharge rate is lower than the prequeue capacity. This difference is called the capacity drop. The magnitude of capacity drop varies over a wide range, depending on the local traffic conditions. However, it is unknown what determines the capacity drop value. No thorough empirical analysis has yet revealed a reliable relationship between the capacity drop and the congestion level. This paper fills the gap by revealing, through empirical analysis, the relationship between vehicle speed in congestion and the queue discharge rate. The research studies congested states in which speed ranges from 6 to 60 km/h. The queue discharge rate is shown to increase considerably with increasing speed in the congestion. In contrast to previous research, this study bases the relationship on empirical data collected on freeways, and the data present a sufficiently large observation sample. A discussion about the influence of weather and study site characteristics on the discharge rate indicates that the relationship needs site-specific calibrations. This study provides a better prediction of capacity drop and a better theoretical understanding of the fluctuations in capacity drop.


    Access

    Download

    Check availability in my library

    Order at Subito €


    Export, share and cite



    Title :

    Capacity Drop


    Subtitle :

    Relationship Between Speed in Congestion and the Queue Discharge Rate


    Additional title:

    Transportation Research Record: Journal of the Transportation Research Board


    Contributors:


    Publication date :

    2019-04-04




    Type of media :

    Article (Journal)


    Type of material :

    Electronic Resource


    Language :

    English



    Capacity, Capacity Drop, and Relation of Capacity to the Path Width in Bicycle Traffic

    Wierbos, Maria J. / Knoop, Victor L. / Hänseler, Flurin S. et al. | Transportation Research Record | 2019


    Directing Traffic to Increase Passenger Drop-Off Capacity

    von Bartheld, Natasha R. / Budhecha, Sonia K. / von Bartheld, Christopher S. | Transportation Research Record | 2011


    Low drop-bottom gondola car, 80,000 lbs. Capacity

    Engineering Index Backfile | 1901


    Hysteresis and Capacity Drop Phenomena in Freeway Networks

    Saberi, Meead / Mahmassani, Hani S. | Transportation Research Record | 2013