Abstrac&--In an effort to relieve peak hour congestion on freeways, various ramp metering algorithms have been employed to regulate the inputs to freeways from entry ramps. In this paper, we consider a freeway system comprised of a freeway section and its entry/exit ramps, and formulate the ramp control problem as a dynamic optimal process to minimize the total time spent in this system. Within...

This paper proposes a novel identification algorithm to the freeway steady-state speed-density balance relational expression of the Markos Papageorgiou’s freeway traffic flow model. Two stages are involved. First, use the power series principle to transform this relational expression from nonlinear model into linear model. Second,use the least squares method to identify the linear model and fur...

The recently developed traffic-responsive feedback control strategy HERO (HEuristic Ramp metering cOordination), that coordinates local ramp-metering actions in freeway networks, was implemented at the M1/M3 Freeway in Queensland, Australia. HERO employs an extended version of the feedback regulator ALINEA at the local level. HERO outperforms uncoordinated local ramp metering and approaches the...

One of the major criticisms of ramp-metering has been the delay caused on the ramps because of the queues created by ramp control strategies. However, recently, several researchers proposed strategies that explicitly take into account ramp queues when determining metering rates. In this paper, an isolated “feedback” based ramp-metering strategy using modeling is presented. In addition to the re...

California freeway travelers suffer large and variable congestion delay. The delay is due to operational inefficiency, excess demand, and unforseen events. Operational inefficiency reduces speed and may cause queue spillovers that reduce exiting flows. Excess demand creates delay on ramps. Unforseen events such as accidents temporarily reduce capacity. The Cell Transmission Model of a freeway w...

Freeway capacity decreases at sags due to local changes in car-following behavior. Consequently, sags are often bottlenecks in freeway networks. This article presents a microscopic traffic model that reproduces traffic flow dynamics at sags. The traffic model includes a new car-following model that takes into account the influence of freeway gradient on vehicle acceleration. The face-validity o...

This paper presents a freeway driving cycle (FDC) construction method based on traffic information. A float car collected different type of roads in California and we built a velocity fragment database. We selected a real freeway driving cycle (RFDC) and established the corresponding time traffic information tensor model by using the data in California Department of Transportation performance m...