Analysis and evaluation of ramp metering algorithms. This thesis presents an evaluation study of two ramp metering algorithms. Draft research reportresearch project agreement no. Evaluation and improvement of the stratified ramp metering. A training manual for freeway operations engineers, ward 481. Todays cooperative ramp metering algorithms adjust the metering rate for every on ramp according to the overall traffic state on the highway and can establish additional. This primer poses ramp metering as a potential tool to address commonly occurring congestion and safety issues. Metering keeps traffic flowing at or near freeflow speed and at or near maximum flow. Feedback ramp metering in intelligent transportation. Read about the case studies that support the use of coordinated ramp signals on motorways.
Evaluation of a fuzzy logic ramp metering algorithm. In evaluating algorithms, are the maintenance and operating costs. In september 2000, all 430 ramp meters were turned off in the twin cities region in response to a mandate from the mn state legislature, following citizen complaints. Ramp metering is commonly used in major metropolitan areas to reduce freeway delay and improve safety. Ramp metering signals passage sensor advanced sign to warn that metering is on freeway end of queue sensor ramp metering signal cycles between redgreen in response to traffic conditions fed to the ramp meter controller. Evaluation and improvement of the stratified ramp metering algorithm through microscopic simulation the minnesota department of transportation mndot has a long history of using ramp metering as a traffic management strategy, though in recent years, some members of the public have questioned the effectiveness of the metering system.
Specifically, with suitable parameter settings, the new system can reduce the total time spent tts by motorway users by 18. As part of this research project, researchers collected data at several sites in houston, texas. Metering or ramp metering is the application of traffic control to freeway onramps to limit the rate of flow entering freeway sections metering has several purposes. Evaluation of onramp control algorithms institute of. For the coordinated ramp metering algorithms, the most commonly used algorithms are based on realtime information from freew ay mainline detectors. This week well use meters at two more interchanges bangerter highway and 14600 s. The fuzzy logic ramp metering algorithm is specifically designed to handlepractical situations, without the need to modify the control parameters. The purpose of this thesis was to develop a foundation for future research on ramp metering. Local ramp metering algorithms only take into account traffic conditions near a single ramp, while coordinated algorithms try to optimize traffic over an area. This paper assesses the performance of two ramp metering algorithms namely alinea and hero individually and in combination with vsl strategies for a critical bottleneck section of auckland motorway.
Evaluation of ramp control algorithms using a microscopic traffic. Department of civil engineering university of minnesota 500 pillsbury dr s e. Ramp metering swarm to control whole freeway corridors. Evaluation of coordinated and local ramp metering algorithms. Signal for success this basic introduction to ramp metering is intended for local decisionmakers and the public, and features testimonials from officials of several cities. Development and comparative evaluation of ramp metering. It provides traffic theory fundamentals and then the design of feedback controllers for isolated and coordinated ramp metering problems. The ramp metering signals are automated to only operate when needed, switching off when metering is no longer required.
Can a predictive algorithm be used to start ramp meters before the freeway breaks down. Development of algorithms to improve ramp metering system. Compared with a widely used rampmetering algorithm alinea, the new system shows superior performance on improving both traffic efficiency and user equity. Ramp metering average 20082009 after ramp metering 2010 number of accidents per year number of accidents number of accidents per year accidents on i435 dropped 64% after the ramp meters were installed. Ramp meters are special traffic signals at the end of a freeway onramp that regulate the flow of traffic. Feedback ramp metering in intelligent transportation systems.
These distances are constrained by ramp geometry, location of signal pole, and the placement of excessive queue detector. Ramp management and control handbook chapter 5 ramp. Ramp meters are used at freeway onramps to manage the rate of automobiles entering the freeway. To resolve traffic congestion on urban highways, it is necessary to apply new traffic control approaches like ramp metering, variable speed limit control vslc, etc. A ramp meter, ramp signal, or metering light is a device, usually a basic traffic light or a twosection 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. In the local traffic responsive metering component of the helper algorithm, each meter selects one of six available metering rates based on localized upstream. In this report ramp metering algorithms and the strategies for implementing them are examined. Although the ramp metering algorithms that underlay these systems are based on relatively simple. First use of algorithms beyond just timing patterns. The general method of ramp metering is explained with its implementations and further approaches. Pdf development and evaluation of ramp metering algorithms. Ramp metering control based on the qlearning algorithm. Enhancing ramp metering algorithms with the use of.
Overview of ramp metering due to the growth of metropolitan areas and tightening of fiscal belts, the need for effective and financially viable freeway management tools is unprecedented. Appendix to txdot roadway design manual introduction engineers install ramp meters to address the following three operational objectives. Feedback ramp metering control in intelligent transportation systems is the first book on the topic of using feedback control also called realtime traffic control or adaptive control by some traffic engineers in ramp metering. The minnesota zone algorithm, a stratified zone metering. Ramp metering, or onramp control, is designed to determine a metering rate for each controlled onramp based on traffic conditions of part or whole of the corridor.
There was no installation or build documentation available. Those proposed ramp metering algorithms awaiting further assessment include the ball aerospace fhwa ramp metering algorithm report 4, 1998. It does this by 1 smoothing the flow of traffic at the merge and thereby increasing effective freeway capacity and safety and 2 reducing the traffic entering the freeway which reduces the volume to. One of the most common and most effective approaches is ramp metering.
Ramp metering signals switch on automatically to manage mainline traffic density within the available motorway capacity. Experience gained during the installation, calibration and operation of the first 30 sites suggested that further benefits could be generated from the ramp metering system by further development of certain aspects of the system algorithms. A comparative study among three ramp metering algorithms used in the greater seattle area by cynthia taylor deirdre meldrumresearch engineer associate professordepartment of electrical. Generally it is possible to divide ramp metering algorithms in two major categories. If there are too many vehicles on the ramp, this causes back ups onto local streets. Recommend moving the argument to a separate article perhaps arguments against ramp metering and keeping this article objective.
Alinea is a local control algorithm and flow is an area wide. Maximizing the flow 6 during the campaign kc scout explained to motorists that they are complying with the ramp meters when they bring their cars to a full or rolling stop at a ramp meter signal that displays a red light. Adaptive ramp metering system that includes a roadside warning beacon and a stop bar used to trigger the ramp meter signal. Most important part of fig the ramp metering system is the algorithm which determines the access rate reduction for every onramp flow. This report summarizes the history and the current state of existing ramp metering algorithms, as the last comprehensive summary of ramp metering algorithms was completed in 1999 by bogenberger and may. The ramp metering policy provides a balance between maximizing the efficiency of the freeway system with traffic flow on the local streets while keeping ramp waits to less than 4 minutes.
For every metered ramp, a meter ratemainline occupancy. A comparative study among three ramp metering algorithms used in the greater seattle area, ward 481. The rtmc then changes the timing on the meter so that more vehicles can. Proposed enhancements are presented for two algorithms, as follows. Evaluation of a fuzzy logic ramp metering algorithm wsdot. Coordinated ramp metering with equity consideration using. Udot uses ramp meters at over 70 locations across the wasatch front to help control traffic flow on i15. This research recommended that the queue detector be installed at least 250 feet downstream of the intersection to provide a safe stopping distance behind a standing queue at the meter.
Basic ramp meter types ramp meters are broken into five different types, dependent upon the number of lanes required for a location and the usage of highoccupant vehicle lanes for priority treatment. A fuzzy logic ramp metering algorithm was implemented on 126 ramps in the greater seattle area. Feedback ramp metering in intelligent transportation systems is the first book on the topic of using feedback control also called realtime traffic control or adaptive control by some traffic engineers in ramp metering. The decrease is greater than that found in ramp meter evaluation studies in. Because trafficpatterns and performance objectives vary from location to location and from year to year, itis important that the algorithm is tunable. The local and bottleneck algorithms often oscillate between these opposing objectives, for a couple of reasons. A programmers guide to the fuzzy logic ramp metering. Algorithm design, user interface, and optimization procedure for a fuzzy logic ramp metering algorithm. Design, field implementation and evaluation of adaptive. Freeway sensors detect traffic and feed information to the ramp meter controller end of queue sensor detects when. This article seems like more of an argument against ramp metering than a neutral discussion about ramp metering. Two multipleramp study sites were evaluated by comparing the fuzzy logic controller flc to the other two ramp metering algorithms in operation at those sites over a fourmonth period.
I540 westbound ramp metering analysis final report atkins i540 westbound ramp metering analysis final report i march 11, 2014 i 37599 2 notice this document and its contents have been prepared and are intended solely for the north carolina department of transportations ncdot information and use in relation to this project. Ramp metering mitigates congestion by managing the rate of traffic entering the freeway from the onramp breaks up traffic platoons on ramps into smaller platoons that can more easily merge with the heavily congested freeway traffic. As a case study, three wellknown onramp metering algorithms, including fixedtime, alinea and flow, were evaluated via traffic simulation on shenzhen chunfeng expressway on various traffic. A comparative study between three ramp metering algorithms used in the greater seattle area, ward 481. Two multipleramp study sites were evaluated by comparing. In this paper, the following rampmetering algorithms were tested. For the model validation process, travel time survey conducted by queensland transport was used.
Next, the writers propose specific enhancements to existing rampmetering algorithms that incorporate probabilityofbreakdown models. Traffic responsive ramp meters can be divided into two categories. The system uses a dynamic suite of algorithms that make combined decisions, aiming to balance ramp queues and wait times in order to give all road users a fair go. The last comprehensive summary of ramp metering algorithms completedwas in 1999 by bogenberger and maythis thesis summarizes.