Gridlock
Encyclopedia
Grid plan
The grid plan, grid street plan or gridiron plan is a type of city plan in which streets run at right angles to each other, forming a grid...
where intersections are blocked, preventing vehicles from either moving forwards through the intersection or backing up to an upstream intersection.
The term gridlock is also widely used to describe high traffic congestion
Traffic congestion
Traffic congestion is a condition on road networks that occurs as use increases, and is characterized by slower speeds, longer trip times, and increased vehicular queueing. The most common example is the physical use of roads by vehicles. When traffic demand is great enough that the interaction...
with minimal flow (a "traffic jam"), whether or not a blocked grid system is involved. By extension, the term has been applied to situations in other fields where flow is stalled by excess demand, or in which competing interests prevent progress.
Cause
The traditional form of gridlock is caused by traffic heading in one direction across an intersection. This traffic is then stopped, by sometimes too much capacity for the roadway or an accident, blocking the intersection. The drivers in the other direction then go into the blocked intersection trying to get through. In many jurisdictions, drivers are prohibited from entering an intersection at a green light if there is no room for them to clear the intersection. If drivers follow this rule of the roadRule of the road
Rule of the road may refer to:*Right- and left-hand traffic, regulations requiring all vehicular traffic to keep either to the left or the right side of the road...
, gridlock will be prevented and traffic will only be slow in the direction that is actually congested. One method of reducing gridlock is to aggressively enforce penalties for vehicles that block intersections.
Another type of gridlock can occur during traffic surges between highway on-ramps and off-ramps located within a quarter mile of each other. Traffic exiting the highway may back up and block the entering vehicles.
Gridlock is sometimes cited as an example of the prisoner's dilemma
Prisoner's dilemma
The prisoner’s dilemma is a canonical example of a game, analyzed in game theory that shows why two individuals might not cooperate, even if it appears that it is in their best interest to do so. It was originally framed by Merrill Flood and Melvin Dresher working at RAND in 1950. Albert W...
(from game theory
Game theory
Game theory is a mathematical method for analyzing calculated circumstances, such as in games, where a person’s success is based upon the choices of others...
). Mutual cooperation among drivers would give the maximum benefit (prevention of gridlock), but this may not happen because of the desire to maximize one's own benefit (shortest travel time) given the uncertainty about the other drivers' commitment to cooperation.
New York City
New York City
New York is the most populous city in the United States and the center of the New York Metropolitan Area, one of the most populous metropolitan areas in the world. New York exerts a significant impact upon global commerce, finance, media, art, fashion, research, technology, education, and...
, drivers who "block the box
Box junction
A box junction is a traffic control measure designed to prevent gridlock at busy road junctions. The surface of the junction is marked with a criss-cross grid of diagonal painted lines , and vehicles may not enter the area so marked unless their exit from the junction is clear A box junction is a...
" are subject to a moving violation that comes with a US$90.00 penalty. Mayor Michael Bloomberg
Michael Bloomberg
Michael Rubens Bloomberg is the current Mayor of New York City. With a net worth of $19.5 billion in 2011, he is also the 12th-richest person in the United States...
, noting that the ten minute ticketing process actually contributes to overall traffic congestion
Traffic congestion
Traffic congestion is a condition on road networks that occurs as use increases, and is characterized by slower speeds, longer trip times, and increased vehicular queueing. The most common example is the physical use of roads by vehicles. When traffic demand is great enough that the interaction...
, has recently asked the New York State Legislature to remove “blocking the box” from the moving violation category. This reclassification would give more traffic agents authority to write tickets and change the current ticketing procedure, which requires that the issuing officer physically stop the violating car in traffic.
Virginia Beach, Virginia
In Virginia Beach, VirginiaVirginia Beach, Virginia
Virginia Beach is an independent city located in the Hampton Roads metropolitan area of Virginia, on the Atlantic Ocean at the mouth of the Chesapeake Bay...
, roads around the oceanfront feature signs at every intersection stating "Don't Block the Box", and threatening a $200 fine.
Effects
The obvious impacts are driver frustration and trip delay. Another impact in cities is exacerbated by the presence of urban street canyons, which effectively trap air pollution and increase air pollution exposures of motorists as well as the general urban population. Noise pollution can be aggravated by excessive starting and stopping noise of gridlocked facilities.Alleviating Gridlock
To make a traffic system less susceptible to gridlock, a traffic metering system can be introduced. These systems determine the optimal number of vehicles allowed in a traffic system, and prevent any extra vehicles from entering. This can be done with traffic control devices, such as traffic lights or warning signs, or a better public transportation system. This type of system is used in Zurich, SwitzerlandEtymology
According to the New York Times the word gridlock was coined in New York CityNew York City
New York is the most populous city in the United States and the center of the New York Metropolitan Area, one of the most populous metropolitan areas in the world. New York exerts a significant impact upon global commerce, finance, media, art, fashion, research, technology, education, and...
in the early 1970s. The first appearances of gridlock in newspapers occurred during the 1980 New York City transit strike
1980 New York City transit strike
The 1980 New York City transit strike in New York City was the first work stoppage at the New York City Transit Authority since 1966. 34,000 members of Transport Workers Union Local 100 walked off their jobs on April 1, 1980, in a strike with the goal of increasing the wage for contracted workers...
. The word is attributed to Sam Schwartz
Sam Schwartz
Samuel I. Schwartz, a.k.a. Gridlock Sam, is one of the leading transportation engineers in the United States, and is widely believed to be the man responsible for popularizing the phrase gridlock. Educated at Brooklyn College and the University of Pennsylvania, he originally worked as a cabbie...
, who was then the chief traffic engineer for the New York City Department of Transportation
New York City Department of Transportation
The New York City Department of Transportation is responsible for the management of much of New York City's transportation infrastructure...
at the time of the strike. Schwartz said the word gridlock was used internally in his department during the 1970s, perhaps as early as 1971. Writing up a memo of emergency recommendations
for senior officials, he recalled the words of a colleague several years earlier who had been analyzing a
proposal to close Broadway to vehicular traffic. His colleague gave the plan the thumbs-down, worrying that it would simply “lock up the grid.” Schwartz was always struck by that image and titled his 1980 memo “Gridlock Prevention Plan.”
In another interview Mr. Schwartz said that he coined the term in the mid 1970s with fellow traffic engineer, Roy Cottam, who " was a little paranoid and thought he would be blamed for gridlock and so he gave me all the credit."
China
The August 2010 traffic jam in the BeijingBeijing
Beijing , also known as Peking , is the capital of the People's Republic of China and one of the most populous cities in the world, with a population of 19,612,368 as of 2010. The city is the country's political, cultural, and educational center, and home to the headquarters for most of China's...
-Zhangjiakou
Zhangjiakou
Zhangjiakou, also known also by several other names, is a prefecture-level city in northwestern Hebei province of North China, adjacent to Beijing to the southeast. Its administrative area has a population of 4.35 million, and covers...
highway in Hebei
Hebei
' is a province of the People's Republic of China in the North China region. Its one-character abbreviation is "" , named after Ji Province, a Han Dynasty province that included what is now southern Hebei...
province, China
People's Republic of China
China , officially the People's Republic of China , is the most populous country in the world, with over 1.3 billion citizens. Located in East Asia, the country covers approximately 9.6 million square kilometres...
, is considered the world's worst traffic jam ever, as traffic congestion stretched more than 100 kilometres (62.1 mi) from August 14 to the 26, including at least 11 days of total gridlock, with some drivers spending up to 5 days to cross this stretch of highway. The event was caused by a combination of road works and thousands of coal trucks from Inner Mongolia
Inner Mongolia
Inner Mongolia is an autonomous region of the People's Republic of China, located in the northern region of the country. Inner Mongolia shares an international border with the countries of Mongolia and the Russian Federation...
’s coalfields that travel daily to Beijing. The New York Times has called this event the "Great Chinese Gridlock of 2010."
Brazil
According to TimeTime (magazine)
Time is an American news magazine. A European edition is published from London. Time Europe covers the Middle East, Africa and, since 2003, Latin America. An Asian edition is based in Hong Kong...
magazine, São Paulo
São Paulo
São Paulo is the largest city in Brazil, the largest city in the southern hemisphere and South America, and the world's seventh largest city by population. The metropolis is anchor to the São Paulo metropolitan area, ranked as the second-most populous metropolitan area in the Americas and among...
has the world's worst daily traffic jams. On June 10, 2009, the historical record was set with more than 182 miles (293 km) of accumulated queues out of 522 mi (835 km) being monitored.
France
For several years the traffic jam that occurred in 1980 over a 175 kilometres (108.7 mi) long stretch of the French A6 AutorouteA6 autoroute (France)
The A6, also known as the Autoroute du Soleil, Sun's Motorway, , is an Autoroute in France, linking Paris to Lyon. The motorway starts at Paris's Porte d'Orléans and Porte d'Italie with two branches, numbered A6a and A6b respectively, that join south of Paris...
between Paris
Paris
Paris is the capital and largest city in France, situated on the river Seine, in northern France, at the heart of the Île-de-France region...
and Lyon
Lyon
Lyon , is a city in east-central France in the Rhône-Alpes region, situated between Paris and Marseille. Lyon is located at from Paris, from Marseille, from Geneva, from Turin, and from Barcelona. The residents of the city are called Lyonnais....
was considered the world’s longest.
See also
- Box junctionBox junctionA box junction is a traffic control measure designed to prevent gridlock at busy road junctions. The surface of the junction is marked with a criss-cross grid of diagonal painted lines , and vehicles may not enter the area so marked unless their exit from the junction is clear A box junction is a...
- DeadlockDeadlockA deadlock is a situation where in two or more competing actions are each waiting for the other to finish, and thus neither ever does. It is often seen in a paradox like the "chicken or the egg"...
- computer software analogy - Journal of Transport and Land UseJournal of Transport and Land UseThe Journal of Transport and Land Use is an open access peer-reviewed academic journal covering the interaction of transport and land use that was established in 2008. As of August 2011, it is the official journal of the World Society on Transport and Land Use Research...
- Roadway air dispersion modelingRoadway air dispersion modelingRoadway air dispersion modeling is the study of air pollutant transport from a roadway or other linear emitter. Computer models are required to conduct this analysis, because of the complex variables involved, including vehicle emissions, vehicle speed, meteorology, and terrain geometry...
- Traffic congestion: Reconstruction with Kerner’s three-phase theoryTraffic congestion: Reconstruction with Kerner’s three-phase theoryVehicular traffic can be either free or congested. Traffic occurs in time and space, i.e., it is a spatiotemporal process. However, usually traffic can be measured only at some road locations...