Controlling Traffic Breakdown

Kurzfassung

Traffic breakdowns are described by a balance equation that models the dynamics of jam formation by two contributions: (1) a discharge rate depending on the lenght of the congestion, (2) an adhesion rate mainly depending on the traffic volume of the considered road section. With this balance equation it is feasible to calculate the dynamics of traffic pattern formation especially the first passage time for a transition from free flow condition to congested traffic including the influence of the parameters affecting the discharge and adhesion rates. Findings based on measurements from German freeways are reported for prompting the assumptions. It leads to an easy to operate definition of the capacity of a road section. How speed limits, lane closures, keep in lane recommendations and ramp metering influence the discharge and adhesion rate is discussed both from a theoretical point of view and from field observations exploring freeway sections with and without corridor control systems. Starting with the cumulative probability for breakdowns the change in the incident duration distribution is calculated and qualitatively given. The paper concludes with recommendations for a comprehensive operation improvement and provides necessary steps for a long lasting stabilization of traffic for a given traffic flow time series pattern.