A method is presented to divide the measured total congestion in any freeway section into three ‘slices’: (1) the delay that collisions cause; (2) the potential reduction in delay at bottlenecks that ideal ramp metering can achieve; and (3) the remaining delay, due mainly to excess demand, but also to all other causes, including non-collision incidents, lane closures, and weather. The method in...

Ramp meters in the Twin Cities have been the subject of a recent test of their effectiveness, involving turning them off for eight weeks. This paper analyzes the results with and without ramp metering for several representative freeways during the afternoon peak period. Seven performance measures: mobility, equity, productivity, consumers’ surplus, accessibility, travel time variation and trave...

Congestion is always a serious problem in many transportation commuting corridors. The need to implement effective control in the corridors has long been recognized by transportation professionals. Ramp metering has been discussed as a viable control strategy on freeways in many places of the US, which may alleviate or at least reduce the delay. In this study, a dynamic ramp metering control mo...

The corridor simulation environment with the capability of modeling various types of traffic control strategies as the external control modules is of critical importance in developing and improving corridor management strategies. In this research, a microscopic network simulation model, Vissim, is used to develop such an environment, where the new stratified Mn/DOT metering algorithm was simula...

Transportation Research Record: Journal of the Transportation Research Board, No. 2278, Transportation Research Board of the National Academies, Washington, D.C., 2012, pp. 1–12. DOI: 10.3141/2278-01 Z. Z. Tian, Department of Civil and Environmental Engineering, University of Nevada, Reno, MS 0258, Reno, NV 89557. N. Wu, Institute for Traffic Engineering, Ruhr University Bochum, 44801 Bochum, G...

The goal of the study is to collect a comprehensive set of freeway and on-ramp operational data for the assessment of ramp metering systems. This paper is a presentation of data and initial findings for vehicle operations on loop ramps; a small subset of the larger project. The results reported here focus on the changes in modal activity (e.g. speed/acceleration) that occurred on two of the stu...

This paper treats the problem of controlling large freeway systems through ramp metering to enhance their efficiency. Following a rigorous discretization methodology, an extension of the CTM model to inhomogeneous freeways with on and off ramps is proposed. Based on passivity theory and the piecewise affine formulation of this model, an LMI formulation is developed to design non-local feedback ...

In this paper, we present a novel switching traffic-responsive ramp-metering controller that adapts to the different traffic dynamics under different congestion conditions—free-flow or congested. The approach of multirate linear quadratic control with integral action (LQI) is employed to compensate for disturbances and to accommodate the difference between the model sampling time and the meteri...

In this paper we deal with model predictive control for ramp metering on motorways. A discussion of the way ramp metering tries to prevent, or postpone, congestion on a motorway is presented. As an example, a real-life motorway in Belgium is presented. We discuss a traffic flow model that is used in a receding horizon framework and we argue that the quality of the fit of the traffic flow model ...

Unlimited access to a motorway network can, in overloaded conditions, cause a loss of capacity. Ramp metering (signals on slip roads to control access to the motorway) can help avoid this loss of capacity. The design of ramp metering strategies has several features in common with the design of access control mechanisms in communication networks. Inspired by models and rate control mechanisms de...