 Ramp metering has been recognized as one of viable strategies of freeway traffic management, which may improve travel speed as well as reduce delay. In this study, a dynamic model is developed to optimize metering rates of a series of on-ramps which maximize the total throughput subject to vehicle density, roadway capacity, and queue length constraints with simultaneous perturbation stochasti...

Freeway merge areas are recognized as the most common segment of recurrent freeway congestion as two separate traffic streams join to merge a single stream. Over the years, several studies have attempted to explain and analyze a merge capacity phenomenon, however relatively few analytical techniques have been developed to evaluate the traffic flow in these areas. This study described a new inte...

Tools for modeling and control of freeway networks by Ajith Muralidharan Doctor of Philosophy in Engineering Mechanical Engineering University of California, Berkeley Professor Roberto Horowitz, Chair This dissertation presents algorithmic tools that are useful to transportation engineers for freeway traffic modeling and control. A modeling framework that utilizes the link-node cell transmissio...

In Akamatsu and Heydecker (2003), we presented a necessary and sufficient condition for the occurrence of capacity paradoxes in general saturated networks, in which there is a queue on each link. The present paper extends that analysis to the more usual case of non-saturated networks, in which there are queues on some links but not on others. First we formulate dynamic user equilibrium (DUE) as...

1 The procedures detailed in the Highway Capacity Manual (HCM 2010) estimate capacity and 2 several operational measures dictating level of service for freeway facilities and surface streets. 3 However, these methods do not consider cases in which spillback occurs from one facility type 4 to another. The queueing effects in oversaturated conditions as they propagate upstream – onto a 5 freeway ...

This article models the interaction between freeway traffic dynamics and capacity-reducing incidents as a stochastic switched system, and analyzes its long-time properties. Incident events on a multi-cell freeway are modeled by a Poisson-like stochastic process. Randomness in the occurrence and clearance of incidents results in traffic dynamics that switch between a set of incident modes (discr...

In this paper, we present a model predictive controller to reduce road traffic congestion in freeway networks. The model predictive controller regulates traffic in the freeway through the use of ramp metering and variable speed limits. The controller uses a Link-Node Cell transmission model (LN-CTM) to represent freeway dynamics. We modify the standard LN-CTM to account for the capacity drop ph...

Traffic jams are an economic and environmental problem in many countries. When traffic demand exceeds the freeway capacity, shock waves can be caused by small disturbances in the traffic flow. Since it is not always desirable or feasible to add more lanes on freeways to overcome capacity problems, alternative methods have been developed to reduce and to dissolve traffic jams. One of these metho...

The capacity of a freeway segment should be measured only when it is an active bottleneck. The properties of flows at active freeway bottlenecks have a bearing on both the definition of capacity and the procedure of capacity analysis. Past studies have examined the flow features at bottlenecks on several freeways in Toronto, Canada, and San Diego, California. This study examined 27 active bottl...

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...