We present in this paper a linear programming framework to address freeway control applications such as ramp metering. After showing the equivalence between the LWR model and a linear optimization problem, several extensions are introduced to model the ramp queues and the capacity drop phenomenon. A wide range of objective functions which are relevant in traffic engineering are then introduced ...

The operations of freeway ramp metering and urban traffic network signal control are independent in most areas. Such situation may cause some conflict between traffic streams of the two subsystems, or, at least, their dynamic interactions have not been taken into account from an overall system viewpoint. Traffic performance can be improved if the controls of these two subnetworks are integrated...

A real-life motorway in Belgium is studied and a comparison is made between a simulation of a morning rush hour situation without control and a simulation of a morning rush hour situation with ramp metering implemented. Two types of controllers are compared: a traditional ALINEA based controller and a model predictive control based ramp metering controller. In order to evaluate the controllers ...

 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...

Dynamic traffic management is an important part of the Dutch transport policy. All kinds of measures have been implemented and assessed on the motorway network, such as the motorway traffic management system with speed limits and queue tail warning, ramp metering, variable message signs, dedicated lanes, peak lanes, incident management, etc. In this paper the focus is on ramp metering, which is...

Measurements taken downstream of freeway/on-ramp merges have verified that discharge flow diminishes when a merge becomes an active bottleneck. We show that metering the on-ramp can recover the higher discharge flow and thereby increase merge capacity. Detailed observations collected using video revealed that the outflow drop following activation was triggered by a queue that formed near the me...

A System-Wide Adaptive Ramp Metering (SWARM) system has been implemented in the Portland, Oregon metropolitan area, replacing the previous pre-timed ramp-metering system that had been in operation since 1981. SWARM has been deployed on six major corridors and operates during the morning and afternoon peak hours. This paper reports on the results of a “before” and “after” evaluation of the perfo...

This study aims to determine whether ramp meters increase the capacity of active freeway bottlenecks. The traffic flow characteristics at twenty-seven active bottlenecks in the Twin Cities have been studied for seven weeks without ramp metering and seven weeks with ramp metering. A methodology for systematically identifying active freeway bottlenecks in a metropolitan area is proposed, which re...

This paper prcseirts aj'2edback contrd design for isolated ramp metering cmtrol. This feedback control design, i:nlike the existing isolated feedback ramp controllers, Glso ta1:es into account (he ramp queue length. Using a !ionlizmr Hm ;ontrol design methodology, we formulate ihe problem in the desired setting to be able to utilize the results of the methodolop.