Ramp meter

Summary

A ramp meter, ramp signal, or metering light is a device, usually a basic traffic light or a two-section signal light (red and green only, no yellow) together with a signal controller, that regulates the flow of traffic entering freeways according to current traffic conditions. Ramp meters are used at freeway on-ramps to manage the rate of automobiles entering the freeway. Ramp metering systems have proved to be successful in decreasing traffic congestion and improving driver safety. Ramp meters are claimed to reduce congestion (increase speed and volume) on freeways by reducing demand and by breaking up platoons of cars. Two variations of demand reduction are commonly cited; one being access rate, the other diversion. Some ramp meters are designed and programmed to operate only at times of peak travel demand; during off-peak times, such meters are either showing a steady green, flashing yellow (Maryland), or are turned off altogether. This allows traffic to merge onto the freeway w

Official source

https://en.wikipedia.org/wiki/Ramp_meter

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Introduce the major elements of transportation systems and traffic engineering-Develop analytical and technical skills in applying the fundamentals of the transport field-Understand the key concepts and physics of the transport phenomena- Connect with real transportation problems and data analytics

The objectives of this course are to present the major elements of traffic operations and to develop basic skills in applying the fundamentals of traffic analysis and control. Students should be able to start applying these skills to model different aspects of congestion in urban systems.

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On the consistency of freeway macroscopic merging models

Nikolaos Geroliminis, Josep Maria Torne Santos

Many first-order macroscopic models for freeway traffic have been developed since the seminal work on the well-known Lighthill-Whitham-Richards, or LWR, continuous model. The asymmetric cell transmission model (ACTM) is a widely accepted macroscopic model integrated into a variety of freeway traffic control frameworks. The model is based on the original cell transmission model; modified merge equations make it computationally tractable for optimization of ramp metering. However, when the common simplistic calibration of the model is used, an infeasible merging behavior is observed at uncontrolled merges, and the resulting queue lengths are not accurately estimated. This paper proposes an elegant analytical relationship, based on traffic flow theory, for calibrating the two parameters involved in the ACTM merge model. The method ensures the physical consistency of the dynamics involved in queue processes in the proximity of a noncontrolled merge junction. This method should be an essential feature of any freeway traffic model.

Natl Acad Sciences2014

National Academy of Sciences2014

PAPABILES: Simulation-based evaluation of the impact of telematics in the Lausanne area: a pilot study. Phase 2: Third lane and ramp metering

Daniel Baumann, Michel Bierlaire, Alexandre Torday

2002