A ramp meter, ramp signal, or metering light is a device, usually a basic
traffic light
Traffic lights, traffic signals, or stoplights – known also as robots in South Africa are signalling devices positioned at road intersections, pedestrian crossings, and other locations in order to control flows of traffic.
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
freeway
A controlled-access highway is a type of highway that has been designed for high-speed vehicular traffic, with all traffic flow—ingress and egress—regulated. Common English terms are freeway, motorway and expressway. Other similar terms ...
s 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
Traffic congestion is a condition in transport that is characterized by slower speeds, longer trip times, and increased vehicular queueing. Traffic congestion on urban road networks has increased substantially since the 1950s. When traffic de ...
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 or are turned off altogether. This allows traffic to merge onto the freeway without stopping. Other ramp meters are designed to operate continuously, only being turned off for maintenance or repairs.
Types
Some metered ramps have bypass lanes for
high-occupancy vehicle
A high-occupancy vehicle lane (also known as an HOV lane, carpool lane, diamond lane, 2+ lane, and transit lane or T2 or T3 lanes) is a restricted traffic lane reserved for the exclusive use of vehicles with a driver and one or more passengers, i ...
s, allowing carpoolers, buses, and other eligible vehicles to skip the
queue and get directly on the highway. In other places such as
Northern California
Northern California (colloquially known as NorCal) is a geographic and cultural region that generally comprises the northern portion of the U.S. state of California. Spanning the state's northernmost 48 counties, its main population centers incl ...
, carpool lanes are still metered, but the queue is typically shorter in comparison to regular lanes. Meters often only operate in
rush hour
A rush hour (American English, British English) or peak hour (Australian English) is a part of the day during which traffic congestion on roads and crowding on public transport is at its highest. Normally, this happens twice every weekday: o ...
periods. Some ramp meters have only one lane of traffic at the signal; others may have two or more lanes of traffic. Generally, meters with multiple lanes only give one lane the green light at a time. In one common configuration, each entrance lane has two signals; a red-yellow-green signal perched overhead over each lane (or mounted high on a pole for a single lane), and a two-phase lamp mounted low on a pole next to the stop line.
The overhead lights are for cars approaching the metering point; the low-mounted two-phase lights are intended to be used by the vehicle at the front of the queue. In normal operation of the ramp meters, only the red and green lamps are used. However, when ramp metering is about to be enabled, the overhead lamps may show flashing or solid yellow to warn drivers to prepare to stop. (Once ramp metering is turned on, there is no further need for the yellow lamp.) In California, some meters allow two or three cars to proceed on a green light. These meters use red-yellow-green signals on both the upper and lower mounts on the pole, and operate in a standard green-yellow-red fashion.
In Ontario, the ramp meter lights are always green when there are no restrictions in place for traffic to proceed.
The sophistication and extent of a ramp metering system should be based on the amount of improvement desired, existing traffic conditions, installation costs, and the continuing resource requirements that are necessary to operate and maintain the system effectively. The simplest form of control is a fixed time operation. It performs the basic functions of breaking up platoons into single-vehicle entries and setting an upper limit on the flow rates that enter the freeway. Presence and passage detectors may be installed on the ramp to actuate and terminate the metering cycles, but the metering rate is based on average traffic conditions at a particular ramp at a particular time. This type of operation provides the benefits associated with accident reductions, but is not as effective in regulating freeway volumes because there is no input about mainline traffic. Pre-timed control can be implemented on any number of ramps, and is often implemented as an initial operating strategy until individual ramps can be incorporated into a traffic responsive system. The next level of control, traffic responsive, establishes metering rates based on actual freeway conditions. The local traffic responsive approach utilizes detectors and a micro-processor to determine the mainline flow in the immediate vicinity of the ramp and the ramp demand to select an appropriate metering rate. Traffic responsive control also permits ramp metering to be used to help manage demand when incidents occur on the freeway, i.e. reduce the metering rate at ramps upstream of the incident and increase the rate at ramps downstream. System-wide control is a form of traffic responsive control but operates on the basis of total freeway conditions. Centralized computer controlled systems can handle numerous ramps in a traffic responsive scheme and feature multiple control programs and overrides. Control strategies can also be distributed among individual ramps. A significant feature of system control is interconnection that permits the metering rate at any ramp to be influenced by conditions at other locations. Denver showed that this type of control has significant benefits when properly applied.
System control need not be limited to the freeway and its ramps. The concept of integrated traffic control combines or coordinates freeway and arterial street control systems to operate on the basis of corridor wide traffic conditions. The potential advantages of integrated control include reduced installation and operating costs, corridor wide surveillance, better motorist information, and quicker and coordinated use of all of the control elements (meters, signals, signs, etc.) in response to real time traffic conditions. Simulation results from one study showed that, during an incident, coordination of arterial traffic signals and ramp meters can improve the traffic performance of a corridor.
Ramp metering signal controls
Ramp meter signals are set according to the current traffic conditions on the road. Detectors (generally an
induction loop) are installed in the road, both on the ramp and on the main road which measure and calculate the traffic flow, speed and occupancy levels. These are then used to alter the number of vehicles that can leave the ramp. The more congested the main freeway, the fewer vehicles are allowed to leave the ramp, this is effected by giving longer red times to the traffic signals.
Much research is currently being carried out into the most appropriate algorithms for controlling ramp meter signals. Some algorithms that are in use or have been evaluated are
ALINEA, demand control and fuzzy algorithms.
Demand control algorithms
The demand control algorithms are examples of
feed-forward control. One version of the demand control algorithm is the RWS strategy used in the Netherlands. In this algorithm the number of vehicles that the signals allow off the ramp is calculated as the difference between the flow before the ramp and the pre-specified capacity of the road.
Ramp metering in North America
This first application involved a
police
The police are a Law enforcement organization, constituted body of Law enforcement officer, persons empowered by a State (polity), state, with the aim to law enforcement, enforce the law, to ensure the safety, health and possessions of citize ...
officer who would stop traffic on an entrance ramp and release vehicles one at a time at a predetermined rate, so that the objectives of safer and smoother merging onto the freeway traffic was easier without disrupting the mainline flows.
Ramp metering was first implemented in 1963 on the Eisenhower Expressway (
Interstate 290) in
Chicago
(''City in a Garden''); I Will
, image_map =
, map_caption = Interactive Map of Chicago
, coordinates =
, coordinates_footnotes =
, subdivision_type = List of sovereign states, Count ...
by Adolf D. May, now a UC Berkeley professor. Development in systems control theory allowed for improved traffic regulation throughout the early 1970s, pioneered by Leif Isaksen in his paper "Suboptimal Control of Large Scale Systems with Application to Freeway Traffic Regulation." Since then ramp-meters have been systematically deployed in many urban areas including
Los Angeles
Los Angeles ( ; es, Los Ángeles, link=no , ), often referred to by its initials L.A., is the largest city in the state of California and the second most populous city in the United States after New York City, as well as one of the world ...
;
San Diego
San Diego ( , ; ) is a city on the Pacific Ocean coast of Southern California located immediately adjacent to the Mexico–United States border. With a 2020 population of 1,386,932, it is the eighth most populous city in the United States ...
;
Sacramento
)
, image_map = Sacramento County California Incorporated and Unincorporated areas Sacramento Highlighted.svg
, mapsize = 250x200px
, map_caption = Location within Sacramento ...
; the
San Francisco Bay Area
The San Francisco Bay Area, often referred to as simply the Bay Area, is a populous region surrounding the San Francisco, San Pablo, and Suisun Bay estuaries in Northern California. The Bay Area is defined by the Association of Bay Area G ...
;
Fresno
Fresno () is a major city in the San Joaquin Valley of California, United States. It is the county seat of Fresno County and the largest city in the greater Central Valley region. It covers about and had a population of 542,107 in 2020, maki ...
;
Philadelphia, Pennsylvania
Philadelphia, often called Philly, is the largest city in the Commonwealth of Pennsylvania, the sixth-largest city in the U.S., the second-largest city in both the Northeast megalopolis and Mid-Atlantic regions after New York City. Since ...
;
Seattle
Seattle ( ) is a seaport city on the West Coast of the United States. It is the seat of King County, Washington. With a 2020 population of 737,015, it is the largest city in both the state of Washington and the Pacific Northwest region o ...
;
Spokane
Spokane ( ) is the largest city and county seat of Spokane County, Washington, United States. It is in eastern Washington, along the Spokane River, adjacent to the Selkirk Mountains, and west of the Rocky Mountain foothills, south of the Ca ...
;
Denver
Denver () is a consolidated city and county, the capital, and most populous city of the U.S. state of Colorado. Its population was 715,522 at the 2020 census, a 19.22% increase since 2010. It is the 19th-most populous city in the Unit ...
;
Phoenix;
Las Vegas
Las Vegas (; Spanish for "The Meadows"), often known simply as Vegas, is the 25th-most populous city in the United States, the most populous city in the state of Nevada, and the county seat of Clark County. The city anchors the Las Veg ...
;
Salt Lake City
Salt Lake City (often shortened to Salt Lake and abbreviated as SLC) is the capital and most populous city of Utah, United States. It is the seat of Salt Lake County, the most populous county in Utah. With a population of 200,133 in 2020, th ...
;
Portland, Oregon
Portland (, ) is a port city in the Pacific Northwest and the largest city in the U.S. state of Oregon. Situated at the confluence of the Willamette and Columbia rivers, Portland is the county seat of Multnomah County, the most populous ...
;
Minneapolis-St. Paul;
Milwaukee
Milwaukee ( ), officially the City of Milwaukee, is both the most populous and most densely populated city in the U.S. state of Wisconsin and the county seat of Milwaukee County. With a population of 577,222 at the 2020 census, Milwaukee i ...
;
Columbus
Columbus is a Latinized version of the Italian surname "''Colombo''". It most commonly refers to:
* Christopher Columbus (1451-1506), the Italian explorer
* Columbus, Ohio, capital of the U.S. state of Ohio
Columbus may also refer to:
Places ...
;
Cincinnati
Cincinnati ( ) is a city in the U.S. state of Ohio and the county seat of Hamilton County. Settled in 1788, the city is located at the northern side of the confluence of the Licking and Ohio rivers, the latter of which marks the state line w ...
;
Houston
Houston (; ) is the most populous city in Texas, the most populous city in the Southern United States, the fourth-most populous city in the United States, and the sixth-most populous city in North America, with a population of 2,304,580 ...
;
Atlanta
Atlanta ( ) is the capital and most populous city of the U.S. state of Georgia. It is the seat of Fulton County, the most populous county in Georgia, but its territory falls in both Fulton and DeKalb counties. With a population of 498,7 ...
;
Miami
Miami ( ), officially the City of Miami, known as "the 305", "The Magic City", and "Gateway to the Americas", is a coastal metropolis and the county seat of Miami-Dade County in South Florida, United States. With a population of 442,241 at ...
;
Washington, DC
)
, image_skyline =
, image_caption = Clockwise from top left: the Washington Monument and Lincoln Memorial on the National Mall, United States Capitol, Logan Circle, Jefferson Memorial, White House, Adams Morg ...
(only along
Interstate 270 in
Montgomery County, Maryland
Montgomery County is the most populous county in the state of Maryland. As of the 2020 census, the county's population was 1,062,061, increasing by 9.3% from 2010. The county seat and largest municipality is Rockville, although the census-design ...
and
Interstate 395 and
Interstate 66
Interstate 66 (I-66) is an east–west Interstate Highway in the eastern United States. It runs from an interchange with I-81 near Middletown, Virginia, on its western end to an interchange with U.S. Route 29 (US 29) in Washing ...
in
Arlington County, Virginia
Arlington County is a county in the Commonwealth of Virginia. The county is situated in Northern Virginia on the southwestern bank of the Potomac River directly across from the District of Columbia, of which it was once a part. The county ...
);
Kansas City, Missouri
Kansas City (abbreviated KC or KCMO) is the largest city in Missouri by population and area. As of the 2020 United States census, 2020 census, the city had a population of 508,090 in 2020, making it the List of United States cities by populat ...
;
and along the
Queen Elizabeth Way
The Queen Elizabeth Way (QEW) is a 400-series highway in the Canadian province of Ontario linking Toronto with the Niagara Peninsula and Buffalo, New York. The freeway begins at the Peace Bridge in Fort Erie and travels around the western ...
in
Mississauga, Ontario
Mississauga ( ), historically known as Toronto Township, is a city in the Canadian province of Ontario. It is situated on the shores of Lake Ontario in the Regional Municipality of Peel, adjoining the western border of Toronto. With a popu ...
(Toronto-bound ramps from Cawthra Road, Hurontario Street, Mississauga Road, Erin Mills Parkway, Winston Churchill Boulevard, Ford Drive) Canada since the 1970s.
In the early 1970s, this traffic control practice drew the attention of the
U.S. Environmental Protection Agency
The Environmental Protection Agency (EPA) is an Independent agencies of the United States government, independent executive agency of the United States federal government tasked with environmental protection matters. President Richard Nixon pro ...
, which was looking for innovative ways to reduce air pollution in California by make the transportation system more effective.
Ramp meters are commonplace in the
New York City
New York, often called New York City or NYC, is the List of United States cities by population, most populous city in the United States. With a 2020 population of 8,804,190 distributed over , New York City is also the L ...
,
Los Angeles
Los Angeles ( ; es, Los Ángeles, link=no , ), often referred to by its initials L.A., is the largest city in the state of California and the second most populous city in the United States after New York City, as well as one of the world ...
,
San Francisco
San Francisco (; Spanish for " Saint Francis"), officially the City and County of San Francisco, is the commercial, financial, and cultural center of Northern California. The city proper is the fourth most populous in California and 17t ...
,
Chicago
(''City in a Garden''); I Will
, image_map =
, map_caption = Interactive Map of Chicago
, coordinates =
, coordinates_footnotes =
, subdivision_type = List of sovereign states, Count ...
,
Seattle
Seattle ( ) is a seaport city on the West Coast of the United States. It is the seat of King County, Washington. With a 2020 population of 737,015, it is the largest city in both the state of Washington and the Pacific Northwest region o ...
,
Phoenix,
Houston
Houston (; ) is the most populous city in Texas, the most populous city in the Southern United States, the fourth-most populous city in the United States, and the sixth-most populous city in North America, with a population of 2,304,580 ...
,
Atlanta
Atlanta ( ) is the capital and most populous city of the U.S. state of Georgia. It is the seat of Fulton County, the most populous county in Georgia, but its territory falls in both Fulton and DeKalb counties. With a population of 498,7 ...
,
Milwaukee
Milwaukee ( ), officially the City of Milwaukee, is both the most populous and most densely populated city in the U.S. state of Wisconsin and the county seat of Milwaukee County. With a population of 577,222 at the 2020 census, Milwaukee i ...
,
Columbus
Columbus is a Latinized version of the Italian surname "''Colombo''". It most commonly refers to:
* Christopher Columbus (1451-1506), the Italian explorer
* Columbus, Ohio, capital of the U.S. state of Ohio
Columbus may also refer to:
Places ...
, and
Minneapolis-St. Paul metropolitan areas, and they are also found in more than two dozen smaller metropolitan areas. In the New York City metro area, locals refer to ramp meters as "merge lights" and in Houston they're known as "flow signals."
Ramp meters have been withdrawn after initial introduction in several cities, including
Dallas
Dallas () is the third largest city in Texas and the largest city in the Dallas–Fort Worth metroplex, the fourth-largest metropolitan area in the United States at 7.5 million people. It is the largest city in and seat of Dallas County ...
,
San Antonio
("Cradle of Freedom")
, image_map =
, mapsize = 220px
, map_caption = Interactive map of San Antonio
, subdivision_type = Country
, subdivision_name = United States
, subdivision_type1= State
, subdivision_name1 = Texas
, subdivision_ ...
, and
Austin
Austin is the capital city of the U.S. state of Texas, as well as the seat and largest city of Travis County, with portions extending into Hays and Williamson counties. Incorporated on December 27, 1839, it is the 11th-most-populous city ...
, Texas. Disused metering signals can still be found along some parkways surrounding
New York City
New York, often called New York City or NYC, is the List of United States cities by population, most populous city in the United States. With a 2020 population of 8,804,190 distributed over , New York City is also the L ...
and
Detroit
Detroit ( , ; , ) is the largest city in the U.S. state of Michigan. It is also the largest U.S. city on the United States–Canada border, and the seat of government of Wayne County. The City of Detroit had a population of 639,111 at t ...
. Although deactivated shortly after they were added, ramp meters have been reactivated at select interchanges of
Interstate 476
Interstate 476 (I-476) is a auxiliary Interstate Highway of I-76 in the U.S. state of Pennsylvania. The highway runs from I-95 near Chester north to I-81 near Scranton, serving as the primary north–south Interstate corridor throu ...
in suburban
Philadelphia
Philadelphia, often called Philly, is the largest city in the Commonwealth of Pennsylvania, the sixth-largest city in the U.S., the second-largest city in both the Northeast megalopolis and Mid-Atlantic regions after New York City. Since ...
.
Ramp meters were installed along
Interstate 435
Interstate 435 (I-435) is an Interstate Highway beltway that encircles much of the Kansas City metropolitan area within the states of Kansas and Missouri in the United States.
Route description
I-435, a loop route of I-35, is long and i ...
in
Overland Park, Kansas
Overland Park ( ) is the second-most populous city in the U.S. state of Kansas. Located in Johnson County, Kansas, it is one of four principal cities in the Kansas City metropolitan area and the most populous suburb of Kansas City, Missouri. As ...
and
Kansas City, Missouri
Kansas City (abbreviated KC or KCMO) is the largest city in Missouri by population and area. As of the 2020 United States census, 2020 census, the city had a population of 508,090 in 2020, making it the List of United States cities by populat ...
in 2009.
Ramp meters in
Mississauga, Ontario
Mississauga ( ), historically known as Toronto Township, is a city in the Canadian province of Ontario. It is situated on the shores of Lake Ontario in the Regional Municipality of Peel, adjoining the western border of Toronto. With a popu ...
are designed in such a way so that if the queue waiting to enter the
QEW grows to the point where it may back up onto city streets, the meter is lifted and all traffic entering the highway is able to move freely without waiting for the meter. The meter goes back into service once the ramp queue is reduced to a reasonable level. While this method may increase congestion on the highway itself, it has the benefit of keeping city arterials free of stopped traffic waiting in queue. Ramp queues are usually quite short, lasting only 5–6 seconds on average before the driver may continue to the freeway.
Minneapolis–Saint Paul ramp meter experiment
In 2000, a $650,000 experiment was mandated by the Minnesota State Legislature in response to citizen complaints and the efforts of State Senator
Dick Day. The study involved shutting off all 433 ramp meters in the Minneapolis-St. Paul area for eight weeks to test their effectiveness. The study was conducted by
Cambridge Systematics
Cambridge Systematics, Inc. is an independent, employee-owned transportation consultancy firm with corporate headquarters located in Medford, Massachusetts. Cambridge Systematics provides strategic planning and management services, objective analy ...
and concluded that when the ramp meters were turned off freeway capacity decreased by 9%, travel times increased by 22%, freeway speeds dropped by 7% and crashes increased by 26%. However, ramp meters remain controversial, and the
Minnesota
Minnesota () is a state in the upper midwestern region of the United States. It is the 12th largest U.S. state in area and the 22nd most populous, with over 5.75 million residents. Minnesota is home to western prairies, now given over t ...
State Department of Transportation has developed new ramp control strategies. Fewer meters are activated during the course of a normal day than prior to the 2000 study, some meters have been removed, timing has been altered so that no driver waits more than four minutes in ramp queue, and vehicles are not allowed to back up onto city streets.
Mainline metering
A mainline meter throttles traffic flow from one segment of a highway to the next by directly metering the highway's traffic. Such a scheme is typically implemented in specialized situations such as bridges and tunnels. A mainline meter was installed at the
San Francisco–Oakland Bay Bridge
The San Francisco–Oakland Bay Bridge, known locally as the Bay Bridge, is a complex of bridges spanning San Francisco Bay in California. As part of Interstate 80 and the direct road between San Francisco and Oakland, it carries about 260,000 ...
toll plaza in the early 1970s. Similar mainline meters have also been installed downstream from the toll plazas at two other San Francisco Bay crossings, the
San Mateo Bridge and the
Dumbarton Bridge. However, these mainline meters have not yet been activated (as of September 2006). A mainline meter also exists on
California State Route 125 southbound at its junction with
Interstate 8
Interstate 8 (I-8) is an Interstate Highway System, Interstate Highway in the southwestern United States. It runs from the southern edge of Mission Bay (San Diego), Mission Bay at Sunset Cliffs Boulevard in San Diego, San Diego, Californi ...
in
La Mesa, California
La Mesa () is a city in San Diego County, located east of Downtown San Diego in Southern California. The population was 61,121 at the 2020 census, up from 57,065 at the 2010 census. Its civic motto is "the Jewel of the Hills."
History
La Me ...
.
Ramp metering in Europe
Ramp metering has been installed in several countries in Europe, including the United Kingdom, Germany and the Netherlands. A research project, ''EURAMP - European Ramp Metering Project'', funded by the European Union was completed in March 2007. The EURAMP Project Deliverables included information about the results of ramp metering in a number of locations and situations, and whether they were helpful in those situations, and a ''Handbook of ramp metering''.
United Kingdom
![Carnell A19 Site 4 Ramp Metering](https://upload.wikimedia.org/wikipedia/commons/5/59/Carnell_A19_Site_4_Ramp_Metering.jpg)
The first trial in the UK was on the M6 J10 near Walsall in 1986. No more sites were developed for the next two decades until a second 'pilot' study in 2006 by the Highways Agency (HA) concluded that ramp metering provides a net benefit under certain conditions - generally more congested junctions. A Summary Report by the HA, dated November 2007, includes an overview of the background and history, international experience, limitations, system operation, algorithms and implementation of ramp metering. In its conclusion it "envisaged ramp metering will be deployed more widely in the coming period." Ramp metering was then introduced widely in England - Phase 1 involved the implementation of approximately 30 sites and was completed by 2008. Phase 2 followed and as of March 2011 there are 88 Ramp Metering sites on the 4,500 miles (7,242 km) of strategic highways operated and maintained by the HA.
The Netherlands
The first ramp metering in the Netherlands was introduced in 1989. Ramp metering is being introduced more widely in the Netherlands after a pilot study by th
AVV Transport Research Centrewhich concluded that ramp metering can provide a small benefit for the traffic flow on the highway, leading to a higher capacity. Ramp meters can also contribute to decreasing '
rat running
Rat running (also known as rodent running, cut-through driving, or dive-bombing) is the practice by motorists of using residential side streets or any unintended short cut such as a parking lot, delivery service lane or cemetery road instead o ...
'. By 2006 50 ramp meters were installed. This number increases by 4 to 5 each year.
Germany
Ramp metering has been implemented on
Autobahn
The (; German plural ) is the federal controlled-access highway system in Germany. The official German term is (abbreviated ''BAB''), which translates as 'federal motorway'. The literal meaning of the word is 'Federal Auto(mobile) Track' ...
s in several areas in Germany, including the Rhine-Ruhr area, Munich, and Hamburg.
Italy
Ramp metering has been implemented on
Tangenziale di Venezia
The Tangenziale di Mestre (Mestre beltway), or Autostrada A57, was opened to traffic on 3 September 1972 in northern Italy.
Overview
The original design was to have a central dual carriageway as Autostrada A4 (motorway A4), and alongside a sepa ...
(A57) as temporary solution for the increased traffic before the definitive solution (building of the
Passante di Mestre).
Ireland
There is one metered ramp. It is located at J1 on the
M1 Motorway (Ireland)
The M1 motorway ( ga, Mótarbhealach M1) is a motorway in Ireland. It forms the large majority of the N1 national primary road connecting Dublin towards Belfast along the east of the island of Ireland. The route heads north via Swords, Drogheda ...
Northbound. It is on the Entry Ramp from Coolock Lane. It is used when the M1 gets congested due to the M1 Port Tunnel and the M1 meeting a bit further up
Ramp metering elsewhere
Japan
Ramp metering is being installed in Japan in the next few years to keep the flow of traffic moving in Japan. There are plans to install ramp meters on every on-ramp in the Japan motorway system.
Australia
The largest ramp metering network in the country is in
Melbourne
Melbourne ( ; Boonwurrung/ Woiwurrung: ''Narrm'' or ''Naarm'') is the capital and most populous city of the Australian state of Victoria, and the second-most populous city in both Australia and Oceania. Its name generally refers to a metro ...
(managed and controlled through
VicRoads
VicRoads is a government joint venture in the state of Victoria, Australia. In the state, it is responsible for driver licensing and vehicle registration. It is owned and operated through a joint venture between the Victorian government and a ...
) on the
Eastern Freeway and most of all, on the entire inner-city M1 route which includes the
Monash Freeway
The Monash Freeway is a major urban freeway in Victoria, Australia, linking Melbourne's CBD to its south-eastern suburbs and beyond to the Gippsland region. It carries up to 180,000 vehicles per day and is one of Australia's busiest freewa ...
, the
CityLink
CityLink is a network of tollways in Melbourne, Australia, linking the Tullamarine, West Gate and Monash Freeways and incorporating Bolte Bridge, Burnley Tunnel and other works. In 1996, Transurban was awarded the contract to augment two ex ...
Tollway
A toll road, also known as a turnpike or tollway, is a public or private road (almost always a controlled-access highway in the present day) for which a fee (or '' toll'') is assessed for passage. It is a form of road pricing typically implemente ...
, the
West Gate Freeway
The West Gate Freeway is a major freeway in Melbourne, the busiest urban freeway and the busiest road in Australia, carrying upwards of 200,000 vehicles per day. It links Geelong (via the Princes Freeway) and Melbourne's western suburbs to ...
and the metropolitan section (south of the beginning of the
Monash Freeway
The Monash Freeway is a major urban freeway in Victoria, Australia, linking Melbourne's CBD to its south-eastern suburbs and beyond to the Gippsland region. It carries up to 180,000 vehicles per day and is one of Australia's busiest freewa ...
) for the
Princes Freeway
Princes Freeway is a Australian freeway, divided into two sections, both located in Victoria, Australia. The freeway links Melbourne to Geelong in the west, and to Morwell in the east. It continues beyond these extremities as the Princes ...
. There are also various ramp meters on the inner-city section of the
Calder Freeway
Calder Highway is a rural highway in Australia, linking Mildura and the Victoria/New South Wales border to Bendigo, in North Central Victoria. South of Bendigo, where the former highway has been upgraded to freeway-standard, Calder Freeway li ...
.
Brisbane
Brisbane ( ) is the capital and most populous city of the Australian state of Queensland, and the third-most populous city in Australia and Oceania, with a population of approximately 2.6 million. Brisbane lies at the centre of the South ...
's
Pacific Motorway and
Bruce Highway
The Bruce Highway is a major highway in Queensland, Australia. Commencing in the state capital, Brisbane, it passes through areas close to the eastern coast on its way to Cairns in Far North Queensland. The route is part of the Australian Nat ...
(S/Bound Caboolture - Gateway Mwy) also uses ramp metering on some on-ramps, as does the northbound on-ramps of
Perth
Perth is the capital and largest city of the Australian state of Western Australia. It is the fourth most populous city in Australia and Oceania, with a population of 2.1 million (80% of the state) living in Greater Perth in 2020. Perth is ...
's
Kwinana Freeway
The Kwinana Freeway is a freeway in and beyond the southern suburbs of Perth, Western Australia, linking central Perth with Mandurah to the south. It is the central section of State Route 2, which continues north as Mitchell Freeway to C ...
between
Roe
Roe ( ) or hard roe is the fully ripe internal egg masses in the ovaries, or the released external egg masses, of fish and certain marine animals such as shrimp, scallop, sea urchins and squid. As a seafood, roe is used both as a cooked in ...
and
Canning Highway
Canning Highway is an arterial road in Perth, Western Australia, linking the inner Perth suburb of Victoria Park in the north-east, to the port city of Fremantle in the south-west.
The road is mostly a four-lane divided carriageway, with a g ...
s. On most motorways, ramp metering is activated when sensors indicate that traffic is heavy, however, some motorways without sensors use time-based activation.
The 2010 M1 Upgrade in Melbourne installed 62 ramp meters that are coordinated using the HERO suite of algorithms developed by Markos Papageorgiou and Associates from the
Technical University of Crete
The Technical University of Crete (TUC; el, Πολυτεχνείο Κρήτης, ''Polytechneio Kritis'') is a state university under the supervision of the Greek Ministry of Education and was founded in 1977 in Chania, Crete. The first stude ...
. The system was built on the
STREAMS
A stream is a continuous body of surface water flowing within the bed and banks of a channel. Depending on its location or certain characteristics, a stream may be referred to by a variety of local or regional names. Long large streams a ...
platform and utilises the state-of-the-art ITS architecture. All the ramps can be linked when required to resolve motorway bottlenecks before they emerge. The results of a trial improved capacity by 9% over the previous fixed-time ramp-metering system, average speeds increased by 20 km/h (12 MPH) and traffic throughput at bottleneck locations can be reliably maintained around 2200 PCE per lane (the M1 is major freight route to the Port of Melbourne and has a very high heavy articulated vehicle mix. The HERO system takes real time data every 20 seconds from the motorway, ramps and arterial road in order determine the best signal timing for the next 20 seconds. The data detection system comprises Sensys detectors in every freeway lane at 500 m (1,640 feet ) spacings with a minimum detectors at three locations on each ramp including the freeway entrance with the arterial road. The system also manages the arterial road interface with the freeway, balances ramp queues and delays across ramps, and is capable of managing bottlenecks 3–4 km (1.8 - 2.4 mi) downstream of a ramp entrance. The system is also supplemented by real-time travel-time information to key destinations and incident and congestion information displayed on specially designed full-colour VMS on the approaches to the freeway entrance ramps. This information provides sufficient advice for motorists to determine whether or not to use the freeway during incidents etc. The system also provides dynamic ramp closure in the event of a major incident.
New Zealand
Auckland
Auckland (pronounced ) ( mi, Tāmaki Makaurau) is a large metropolitan city in the North Island of New Zealand. The most populous urban area in the country and the fifth largest city in Oceania, Auckland has an urban population of about I ...
has currently 91 ramp meters across the Southern, South Western, Northern and North Western motorways making it the largest
Southern Hemisphere ramp metering system.
[Aydos J.C., O'Brien A. ''SCATS Ramp Metering: Strategies, Arterial Integration and Results'', Proceedings of the 17th International IEEE Conference on Intelligent Transportation Systems, Qingdao, 2014](_blank)
/ref> Ramp metering was installed Auckland-wide after a successful trial on Mahunga Drive in 2004, before the Mangere Bridge.
Traffic data collected from 25 ramp metering sites in 2007 (before ramp metering deployment) and 2009 (after) shows an average 25% improvement in both congestion duration and traffic speed as well as an 8% increase in traffic throughput. The data also shows an average reduction in crashes of 22%. This performance and safety data translates into estimated benefits of US$1.6M per ramp metering site per year.
The system controlling the ramps promotes the traditional coordination among on-ramps as well as real-time integration with traffic signals on the adjacent arterial network allowing the whole road network to be managed as a single integrated network. For example, when motorway incidents adversely impact the adjacent arterial roads, an automatic response to the arterial traffic signals can be triggered to mitigate the impacts of the incident and vice versa. Recurrent and excessive traffic queues at on-ramp and off-ramp can also be managed in an integrated way in real-time. This integrated management is possible in Auckland because the same adaptive SCATS
The Sydney Coordinated Adaptive Traffic System, abbreviated SCATS, is an intelligent transportation system that manages the dynamic (on-line, real-time) timing of signal phases at traffic signals, meaning that it tries to find the best phasing (i ...
system controls both arterial traffic lights and motorway ramp meters.
The term ''Ramp Signalling'' rather than ''Ramp Metering'' is purposefully adopted in New Zealand as a user-oriented name.
South Africa
Ramp meters were, for a while, installed on the Samrand South bound, Old Johannesburg South bound and on New Road North and South bound interchanges on the N1 Ben Schoeman highway
The Ben Schoeman Freeway or Ben Schoeman Highway is the main freeway between Johannesburg and Pretoria, and consists of portions of the M1, N1, and N14. Opened in 1968, it is named after a former Minister of Transport Ben Schoeman, and is un ...
. The ramp metering was part of the Intelligent Transport System launched in October 2007 to aid traffic flow between Johannesburg
Johannesburg ( , , ; Zulu language, Zulu and xh, eGoli ), colloquially known as Jozi, Joburg, or "The City of Gold", is the largest city in South Africa, classified as a Megacity#List of megacities, megacity, and is List of urban areas by p ...
and Pretoria
Pretoria () is South Africa's administrative capital, serving as the seat of the executive branch of government, and as the host to all foreign embassies to South Africa.
Pretoria straddles the Apies River and extends eastward into the foothi ...
.
A ramp meter has also been installed on the northbound on-ramp from Blue Lagoon to the M4 Highway in Durban since early 2007.
Taiwan
Freeways in Taiwan use ramp meters during peak hours since 1993. Traffic enforcement camera
A traffic enforcement camera (also red light camera, speed camera, road safety camera, road rule camera, photo radar, photo enforcement, Gatso, safety camera, bus lane camera, flash for cash, Safe-T-Cam, No contact apprehension camera dependin ...
s are deployed to deter running the red lights, but a bus lane
A bus lane or bus-only lane is a lane restricted to buses, often on certain days and times, and generally used to speed up public transport that would be otherwise held up by traffic congestion. The related term busway describes a roadwa ...
at Taipei Interchange from northbound Chongqing North Road to southbound National Highway No. 1 in northern Datong District, Taipei
Datong District or Tatung is a district of Taipei City, Taiwan. It is located between the Taipei Metro Red Line and eastern shore of the Tamsui River, and between Civic Boulevard and the Sun Yat-sen Freeway. The southern part of this area used ...
allows buses and properly indicated emergency vehicles to bypass the traffic control imposed by the ramp meters.
Turkey
In 2016, two ramp meters were installed on a major highway in Istanbul
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, postal_code = 34000 to 34990
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.[ ] It has been noted that there is a 10% improvement in traffic provement along with 20% decrease in delays.
Enforcement
On some ramp meters, there is a singular red light on the backside of the signal that is synchronized with the red light on the traffic signal that the drivers see when queueing. When the queueing drivers see the red light on the traffic signal, the backside red light is on, when the traffic signal displays green or yellow, the backside red light is off. This allows highway patrol
A highway patrol, or state patrol is either a police unit created primarily for the purpose of overseeing and enforcing traffic safety compliance on roads and highways, or a detail within an existing local or regional police agency that is prima ...
to enforce the metering lights by having an officer
An officer is a person who has a position of authority in a hierarchical organization. The term derives from Old French ''oficier'' "officer, official" (early 14c., Modern French ''officier''), from Medieval Latin ''officiarius'' "an officer," f ...
park their car or motorcycle
A motorcycle (motorbike, bike, or trike (if three-wheeled)) is a two or three-wheeled motor vehicle Steering, steered by a Motorcycle handlebar, handlebar. Motorcycle design varies greatly to suit a range of different purposes: Long-distance ...
on the shoulder
The human shoulder is made up of three bones: the clavicle (collarbone), the scapula (shoulder blade), and the humerus (upper arm bone) as well as associated muscles, ligaments and tendons. The articulations between the bones of the shoulder mak ...
a short distance past the targeted signal, watch the red light for any offenders, and pull them over. Additionally, if the given ramp has a carpool bypass lane, officers from that vantage point may also catch and pull over non-carpoolers who are illegally using the carpool lane to skip past the ramp meter queue.
On westbound I-80
Interstate 80 (I-80) is an east–west transcontinental freeway that crosses the United States from downtown San Francisco, California, to Teaneck, New Jersey, in the New York metropolitan area. The highway was designated in 1956 as one o ...
in Oakland, California
Oakland is the largest city and the county seat of Alameda County, California, United States. A major West Coast port, Oakland is the largest city in the East Bay region of the San Francisco Bay Area, the third largest city overall in the ...
just past the San Francisco–Oakland Bay Bridge, Bay Bridge toll plaza, there is a section with overhead metering lights that cycle when the freeway traffic volumes are high, equipped with Red light camera, cameras that capture license plate images of drivers who run the red light and then send a fine.
References
Patrowicz, G. U.S. Department of transportation, (1995). Ramp metering status in North America (DOT-T-95-17). Washington, D.C.: Federal Highway Administration. http://ntl.bts.gov/lib/jpodocs/repts_pr/3725.pdf
External links
University of Minnesota
- Auckland Ramp Signalling information
{{DEFAULTSORT:Ramp Meter
Traffic signals