1 / 10

GREEN WAVE TRAFFIC OPTIMIZATION

GREEN WAVE TRAFFIC OPTIMIZATION. Definitions and setup. The traffic network is modelled as a directed graph G(V;E) An artery defines a main-path, the major road, through a traffic network

rafi
Download Presentation

GREEN WAVE TRAFFIC OPTIMIZATION

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. GREEN WAVE TRAFFIC OPTIMIZATION

  2. Definitionsand setup • The traffic network is modelled as a directed graph G(V;E) • An artery defines a main-path, the major road, through a traffic network • The cycle time: the time it takes for a traffic signal to get from the start of the green light through the yellow and red and until it again becomes green

  3. Definitions and setup • A phase (or stage) corresponds to a particular state of the red and green lights of the traffic lights in an intersection • The green split is the green-time to cycle-time ratio for the phases of the intersection. • The offset for an intersection is used to accommodate green waves for traffic travelling from intersection to intersection at a specified pace.

  4. Definitions and setup • The performance is evaluated by considering the Measure Of Effectiveness (MOE). Most common is the average delay, but the travel time through the network and number of stops, or some combination of these, is also common. • Choosing MOE depends on: - The type of traffic which should gain benefits - The network - Political objectives

  5. Notation

  6. The optimization problem

  7. Comments • We must solve an optimization problem to obtain the user equilibrium link flows • We have a bilevel optimization problem • Used methods are metaheuristic, for example GA, gradient projection method,…

  8. Types of Traffic Signals • There are three major types of traffic signal systems called pretimed signals, actuated signals and adaptive signals • Pretimed signals use static plans for phase sequences, cycle time and green splits according to the day of time. • Actuated signals function like pretimed signals but with the ability to lengthen the green period by a certain amount, if additional vehicles are observed: impossible to setup green waves. • Adaptive signals are a network of signals which attempts to optimize some MOE in a manner which is at least as intelligent as for actuated signals.

  9. Offline Systems • A feature of adaptive systems is that they are less dependent on a large database of historical flow data since they use online data input from detectors. • They do not have to consider the problem of mutual equilibrium between signal settings and user equilibrium in the same degree. • The offline systems: the mathematical model is presented in the spirit of Problem (1). • Software: TRANSYT, https://www.trlsoftware.co.uk/products/junction_signal_design/transyt

  10. Adaptive Systems • There are three systems presented: RHODES, Phase by Phase, DOGS. • RHODES is the most general (for network-wide optimization). • The DOGS system is specically designed to increase capacity along an arterial. It is very flexible but requires many input parameters. • The phase-by-phase system performs advanced intersection control but had no inherent strategy for coordination.

More Related