Traffic congestion is a condition on any network as use increases and is characterized by slower speeds, longer trip times, and increased queueing. Queueing theory is the mathematical study of waiting lines (or queues ' The most common example is for physical use of roads by vehicles. When traffic demand is great enough that the interaction between vehicles slows the speed of the traffic stream congestion is incurred. As the demand approaches the capacity of a road (or of the intersections along the road), extreme traffic congestion sets in, where vehicles are fully stopped for periods of time, is colloquially known as a traffic jam.

Contents 1 Definition 1.1 Causes 1.1.1 Mathematical theories 1.1.2 Economic theories 1.2 Classification 2 Negative impacts 3 Countermeasures 3.1 Road infrastructure 3.2 Urban planning and design 3.3 Supply and demand 3.4 Traffic management 3.5 Other associated 4 By country 4.1 In Brazil 4.2 In New Zealand 4.3 In the United Kingdom 4.4 In the United States 5 Literature 6 See also 7 References 8 External links

Definition

Causes

Traffic congestion occurs when a volume of traffic or modal split generates demand for space greater than the available road capacity. Mode choice analysis is the third step in the conventional four-step Transportation forecasting model following Trip generation and Trip distribution There are a number of specific circumstances which cause or aggravate congestion; most of them reduce the capacity of a road at a given point or over a certain length, or increase the number of vehicles required for a given throughput of people or goods. A 2005 American study stated that there are seven root causes of congestion, and gives the following summary of their contributions: bottlenecks 40%, traffic incidents 25%, bad weather 15%, work zones 10%, poor signal timing 5%, and special events/other 5%. ^[1] Other causes include conditions where the mode share between high and low occupancy vehicles primarily consists of low occupancy vehicles or of types of vehicle that take up a large quantum of network space per person. Speed and flow can also affect network capacity though the relationship is complex.

Traffic research still cannot fully predict under which conditions a "traffic jam" (as opposed to heavy, but smoothly flowing traffic) may suddenly occur. It has been found that individual incidents (such as accidents or even a single car braking heavily in a previously smooth flow) may cause ripple effects which then spread out and create a sustained traffic jam when, otherwise, normal flow might have continued for some time longer. ^[2]

Mathematical theories

Some traffic engineers have attempted to apply the rules of fluid dynamics to traffic flow, likening it to the flow of a fluid in a pipe. Fluid dynamics is the sub-discipline of Fluid mechanics dealing with fluid flow: Fluids ( Liquids and Gases in motion Congestion simulations and real-time observations have shown that in heavy but free flowing traffic, jams can arise spontaneously, triggered by minor events ("butterfly effects"), such as an abrupt steering maneuver by a single motorist. The butterfly effect is a phrase that encapsulates the more technical notion of sensitive dependence on initial conditions in Chaos theory. Traffic scientists liken such a situation to the sudden freezing of supercooled fluid. ^[3] However, unlike a fluid, traffic flow is often affected by signals or other events at junctions that periodically affect the smooth flow of traffic; matrix entropy models consider the effects of this by "platooning" groups of vehicles and by randomising the flow patterns within individual segments of the network. In Thermodynamics (a branch of Physics) entropy, symbolized by S, is a measure of the unavailability of a system ’s Energy

In the three phase traffic theory of Boris Kerner, congestion is classified into two distinct phases: synchronised flow and wide moving jams (in addition to the first phase, free flow). The three phase traffic theory is an alternative traffic theory developed by Boris Kerner. Boris S Kerner is the pioneer of the much discussed Three phase traffic theory and a leading expert in vehicular traffic theory and the theory of pattern formation in dissipative In synchronised flow, the speeds of the vehicles are low and vary quite a lot between vehicles, but the traffic flow (expressed in vehicles per time unit) remains close to free flow. In wide moving jams, vehicle speeds are more equal and lower, and time delays can be quite large.

Economic theories

Congested roads can be seen as an example of the tragedy of the commons. The Tragedy of the Commons is the title of an influential article written by Garrett Hardin, first published in the journal Science in 1968. Because roads in most places are free at the point of usage, there is little financial incentive for drivers not to over-utilize them, up to the point where traffic collapses into a jam, when demand becomes limited by opportunity cost. Opportunity cost or economic opportunity loss is the value of a product forgone to produce or obtain Privatization of highways and road pricing have both been proposed as measures that may reduce congestion through economic incentives and disincentives. A private highway is a Highway owned and operated for profit by private industry Road pricing is an economic concept regarding the various direct charges applied for the use of Roads The road charges includes Fuel taxes licence fees Congestion can also happen due to non-recurring highway incidents, such as a crash or roadworks, which may reduce the road's capacity below normal levels. In the fields of Architecture and Civil engineering, construction is a process that consists of the Building or assembling of Infrastructure

Economist Anthony Downs, in his books Stuck in Traffic (1992) and Still Stuck in Traffic (2004), offers a dissenting view: rush hour traffic congestion is inevitable because of the benefits of having a relatively standard work day. Anthony Downs is a noted scholar in Public policy and Public administration, and since 1977 is a Senior Fellow at the Brookings Institution in Washington Rush hour at Shinjuku 02JPG|thumb|right|250px|Rush hour at Shinjuku Station, Yamanote Line]] A rush hour or peak hour is a part of the day during which In a capitalist economy, goods can be allocated either by pricing (ability to pay) or by queueing (first-come first-serve); congestion is an example of the latter. Capitalism is the Economic system in which the Means of production are owned by private Persons and operated for Profit and where Instead of the traditional solution of making the "pipe" large enough to accommodate the total demand for peak-hour vehicle travel (a supply-side solution), either by widening roadways or increasing "flow pressure" via automated highway systems, Downs advocates greater use of road pricing to reduce congestion (a demand-side solution, effectively rationing demand), in turn plowing the revenues generated therefrom into public transportation projects. An automated highway system (AHS or Smart Road is a proposed Intelligent transportation system technology designed to provide for Driverless cars on specific rights-of-way Road pricing is an economic concept regarding the various direct charges applied for the use of Roads The road charges includes Fuel taxes licence fees Road pricing itself is controversial, more information is available in the dedicated article. Road pricing is an economic concept regarding the various direct charges applied for the use of Roads The road charges includes Fuel taxes licence fees

Classification

Qualitative classification of traffic is often done in the form of a six letter A-F level of service (LOS) scale defined in the Highway Capacity Manual, a US document used (or used as a basis for national guidelines) worldwide. Level-of-service (LOS is a measure-of-effectiveness by which traffic engineers determine the quality of service on elements of transportation infrastructure The Highway Capacity Manual (HCM is a publication of the Transportation Research Board (TRB in the United States. These levels are used by transportation engineers as a shorthand and to describe traffic levels to the lay public. Transport engineering (alternatively transportation engineering) is the science of safe and efficient movement of people and goods ( Transport) While this system generally uses delay as the basis for its measurements, the particular measurements and statistical methods vary depending on the facility being described. For instance, while the percent time spent following a slower-moving vehicle figures into the LOS for a rural two-lane road, the LOS at an urban intersection incorporates such measurements as the number of drivers forced to wait through more than one signal cycle. ^[4]

Negative impacts

Traffic congestion has a number of negative effects:

• Wasting time of motorists and passengers ("opportunity cost"). Opportunity cost or economic opportunity loss is the value of a product forgone to produce or obtain As a non-productive activity for most people, congestion reduces regional economic health.
• Delays, which may result in late arrival for employment, meetings, and education, resulting in lost business, disciplinary action or other personal losses.
• Inability to forecast travel time accurately, leading to drivers allocating more time to travel "just in case", and less time on productive activities.
• Wasted fuel increases air pollution and carbon dioxide emissions contributing to global warming owing to increased idling, acceleration and braking. Pollution is the introduction of contaminants into an environment that causes instability disorder harm or discomfort to the physical systems or living organisms they are in Global warming is the increase in the average measured temperature of the Increased fuel use may also in theory cause a rise in fuel costs.
• Wear and tear on vehicles as a result of idling in traffic and frequent acceleration and braking, leading to more frequent repairs and replacements.
• Stressed and frustrated motorists, encouraging road rage and reduced health of motorists. Road rage is the behavior by a driver of an automobile or other motor vehicle which thus causes collisions or incidents on roadways
• Emergencies: blocked traffic may interfere with the passage of emergency vehicles traveling to their destinations where they are urgently needed.
• Spillover effect from congested main arteries to secondary roads and side streets as alternative routes are attempted ('rat running'), which may affect neighborhood amenity and real estate prices. Spillover effects are Externalities of economic activity or process upon those who are not directly involved in it In the contexts of Real estate and Lodging, amenities are any tangible or intangible benefits of a property especially those which increase the attractiveness or Real estate is a legal term (in some jurisdictions notably in the USA, United Kingdom

Countermeasures

It has been suggested by some commentators that the level of congestion that society tolerates is a rational (though not necessarily conscious) choice between the costs of improving the transportation system (in infrastructure or management) and the benefits of quicker travel. Others link it largely to subjective lifestyle choices, differentiating between car-owning and car-free households.

Road infrastructure

• Junction improvements
  • Grade separation, using bridges (or, less often, tunnels) freeing movements from having to stop for other crossing movements
  • Ramp signalling, 'drip-feeding' merging traffic via traffic signals onto a congested motorway-type roadway
  • Reducing junctions
    • Local-express lanes, providing through lanes that bypass junction on-ramp and off-ramp zones
    • Limited-access road, roads that limit the type and amounts of driveways along their lengths
• Reversible lanes, where certain sections of highway operate in the opposite direction on different times of the day/ days of the week, to match asymmetric demand. A road junction is a location where vehicular Traffic going in different directions can proceed in a controlled manner designed to minimize accidents Grade separation is the process of aligning a junction of two or more transport axes at different heights ( A ramp meter, ramp signal or metering light is a device usually a basic Traffic light or a two-phase (red and green no yellow light together The traffic light, also known as traffic signal, stop light, traffic lamp, stop-and-go lights, robot or semaphore, Local-express lanes or collector-express lanes are a set of two same-direction one-way multi-lane roadways usually on a Freeway. A limited-access road or controlled-access road is a Road to which access from adjacent properties is limited in some way A driveway is a type of private road for local access to one or a small group of structures and is owned and maintained by an individual or group A reversible lane (called a counterflow lane or contraflow lane in Transport engineering nomenclature) is a Lane in which Traffic This may be controlled by Variable-message signs or by movable physical separation
• Separate lanes for specific user groups (usually with the goal of higher people throughput with fewer vehicles)
  • Bus lanes as part of a busway system
  • HOV lanes, for vehicles with at least three (sometimes at least two) riders, intended to encourage carpooling
    • Slugging, impromptu carpooling at HOV access points, on a hitchhiking or payment basis
    • Market-based carpooling with pre-negotiated financial incentives for the driver

Urban planning and design

City planning and urban design practices can have a huge impact on levels of future traffic congestion, though they are of limited relevance for short-term change. A variable- (also changeable-, electronic-, or dynamic-) message sign, often abbreviated VMS, CMS, or DMS, is A bus lane or bus only lane is a lane on a road restricted to Buses and generally used to speed up public transport otherwise held up by traffic congestions Bus rapid transit ( BRT) is a broad term given to a variety of transportation systems that through improvements to infrastructure vehicles and scheduling attempt to use In Transportation engineering and Transportation planning, a high-occupancy vehicle lane (or HOV lane) is a lane reserved for Vehicles with Carpooling (also known as car-sharing, ride-sharing, lift-sharing) is the shared use of a car by the driver and one or more passengers usually Slugging, also known as casual carpooling, is the practice of forming ad-hoc informal carpools for purposes of Commuting, essentially a variation of ride-share Hitchhiker Program Hitchhiking (also known as thumbing, hitching, autostop or thumbing up a ride) is a means of Transportation A market economy is a realized Social system based on the Division of labour in which the prices of Goods and Services are determined in a Urban design concerns the arrangement appearance and functionality of towns and cities and in particular the shaping and uses of urban Public space.

• Grid plans including Fused Grid road network geometry, rather than tree-like network topology which branches into cul-de-sacs (which reduce local traffic, but increase total distances driven and discourage walking by reducing connectivity). The grid plan or gridiron plan is a type of City plan in which Streets run at right angles to each other forming a grid. The Fused Grid represents the synthesis of two traditional North American approaches to residential neighborhood planning the traditional nineteenth-century Grid plan, and Network topology is the study of the arrangement or mapping of the elements ( links, nodes, etc "Dead End Street" redirects here For the song by The Kinks see Dead End Street (song. This avoids concentration of traffic on a small number of arterial roads and allows more trips to be made without a car. An arterial road is a moderate or high-capacity Road which is immediately below a Highway Level of service.
• Zoning laws that encourage mixed-use development, which reduces distances between residential, commercial, retail, and recreational destinations (and encourage cycling and walking). Mixed-use development is the practice of allowing more than one type of use in a building or set of buildings
• Carfree cities, car-light cities, and eco-cities designed to eliminate the need to travel by car for most inhabitants. A carfree city is a population center that relies primarily on mass transit walking and/or biking for transportation within the city ^[5][6]
• Transit-oriented development are residential and commercial areas designed to maximize access to public transport. TOD in cities Many cities in the USA and Canada are developing TOD policy

Supply and demand

See also: Transportation Demand Management

Congestion can be reduced by either increasing road capacity (supply), or by reducing traffic (demand). Capacity can be increased in a number of ways, but needs to take account of latent demand otherwise it may be used more strongly than anticipated. Induced demand is the phenomenon that after supply increases more of a good is consumed Critics of the approach of adding capacity have compared it to "fighting obesity by letting out your belt" (inducing demand that did not exist before). Obesity is a condition in which excess Body fat has accumulated to such an extent that health may be negatively affected ^[7][8] Reducing road capacity has in turn been attacked as removing free choice as well as increasing travel costs and times.

Increased supply can include:

• Adding more capacity at bottlenecks (such as by adding more lanes at the expense of hard shoulders or safety zones, or by removing local obstacles like bridge supports and widening tunnels)
• Adding more capacity over the whole of a route (generally by adding more lanes)
• Creating new routes
• Traffic management improvements (see separate section below)

Reduction of demand can include:

• Parking restrictions, making motor vehicle use less attractive by increasing the monetary and non-monetary costs of parking, introducing greater competition for limited city or road space. A hard shoulder, or simply shoulder, is a reserved area by the verge of a Road or Motorway. Parking is the act of stopping a Vehicle and leaving it unoccupied for more than a brief time ^[9] Most transport planning experts agree that free parking distorts the market in favour of car travel, exacerbating congestion. ^[10][11]
• Park and ride facilities allowing parking at a distance and allowing continuation by public transport or ride sharing. Park and ride (or incentive parking) facilities are Public transport stations that allow commuters and other people wishing to travel into Carpooling (also known as car-sharing, ride-sharing, lift-sharing) is the shared use of a car by the driver and one or more passengers usually Park-and-ride car parks are commonly found at metro stations, freeway entrances in suburban areas, and at the edge of smaller cities. Parking lot (called a car park in Australia and the UK) is a cleared area that is more or less level and is intended for Parking vehicles A metro station is a railway station for a Rapid transit system often known by names such as "metro" "underground" and "subway"
• Reduction of road capacity to force traffic onto other travel modes. Modal share, or Modal split, is a traffic / transport term which describes the percentage of travellers using a particular type of transportation Methods include traffic calming and the shared space concept. Traffic calming is a set of strategies used by Urban planners and traffic engineers which aim to slow down or reduce Traffic, thereby improving safety Shared space, sometimes called shared surfaces, is a traffic engineering policy to remove the traditional separation between motor vehicles and pedestrians and other
• Road pricing, charging money for access onto a road/specific area at certain times, congestion levels or for certain road users
  • 'Cap and Trade', where only licensed cars are allowed on the roads. Road pricing is an economic concept regarding the various direct charges applied for the use of Roads The road charges includes Fuel taxes licence fees ^[12] A limited quota of car licences are issued each year and traded in a free market fashion. A free market is a Market in which property rights are voluntarily exchanged at a price arranged completely by the mutual consent of sellers and buyers This guarantees that the number of cars does not exceed road capacity while avoiding the negative effects of shortages normally associated with quotas. Economic shortage is a term describing a disparity between the amount demanded for a product or service and the amount supplied in a Market. However since demand for cars tends to be inelastic, the result are exorbitant purchase prices for the licenses, pricing out the lower levels of society, as seen Singapore's Certificate of Entitlement scheme. The Certificate of Entitlement (COE, instituted by the government of Singapore, is a program designed to limit car Ownership, and hence the number of ^[13]
  • Congestion pricing, where a certain area, such as the inner part of a congested city, is surrounded with a cordon into which entry with a car requires payment. Congestion pricing or congestion charges is a system of surcharging users of a Transport network in periods of peak Demand to reduce Traffic congestion The cordon may be a physical boundary (i. e. , surrounded by toll stations) or it may be virtual, with enforcement being via spot checks or cameras on the entry routes. Major examples are Singapore's electronic road pricing, the London congestion charge system, and the Stockholm congestion tax. Singapore The Electronic Road Pricing ( ERP) (Sistem Kadar Jalan Elektronik 电子道路收费系统 scheme is an Electronic toll collection scheme adopted in Singapore The London congestion charge is a fee for some motorists travelling within those parts of London designated as the Congestion Charge Zone (CCZ The Stockholm congestion tax (Trängselskatt i Stockholm also found referred to as the Stockholm congestion charge, is a Congestion pricing system implemented
• Road space rationing, where regulatory restrictions prevent certain types of vehicles from driving under certain circumstances or in certain areas. Road space rationing ( Spanish: Restricción vehicular; Portuguese: Rodízio veicular) is a travel demand management strategy aimed
  • Number plate restrictions based on days of the week, as practiced in several large cities in the world, such as Athens,^[14] Mexico City and São Paulo. Athens (ˈæθənz Αθήνα Athina,) the Capital and largest city of Greece, dominates the Attica periphery as one of the world's Mexico City (in Spanish: Ciudad de México, México DF, México or simply Méjico) is the Capital city of Mexico São Paulo ( is the largest city in Brazil, with its metropolitan area ranking among the largest urban areas in the world ^[15] In effect, such cities are banning a different part of the automobile fleet from roads each day of the week. Mainly introduced to combat smog, these measures also reduce congestion. Smog is a kind of Air pollution; the word "smog" is a Portmanteau of Smoke and Fog. A weakness of this method is that richer drivers can purchase a second or third car to circumvent the ban.
  • Permits, where only certain types of vehicles (such as residents) are permitted to enter a certain area, and other types (such as through-traffic) are banned. ^[15] For example, Bertrand Delanoe, the mayor of Paris, has proposed to impose a complete ban on motor vehicles in the city's inner districts, with exemptions only for residents, businesses, and the disabled. Bertrand Delanoë (born 30 May 1950) /bɛʁtʁɑ̃ dəlanɔe/ ( is a French Politician, and has been the mayor of Paris Paris (ˈpærɨs in English; in French) is the Capital of France and the country's largest city ^[16]
• Policy approaches, which usually attempt to provide either strategic alternatives or which encourage greater usage of existing alternatives through promotion, subsidies or restrictions. A policy is a deliberate plan of action to guide decisions and achieve rational outcome(s
  • Incentives to use public transport, increasing modal shares. This can be achieved through infrastructure investment, subsidies, transport integration, pricing strategies that decrease the marginal cost/fixed cost ratios^[17][18], and improved timetabling. In Economics and Finance, marginal cost is the change in Total cost that arises when the quantity produced changes by one unit Fixed costs are business Expenses that are not dependent on the level of production or sales See also Timetable A public transport timetable is a listing of the times that public transport services arrive and depart specified locations ^[19][20]
  • Cycling promotion through legislation, cycle facilities, subsidies, and awareness campaigns. Utility cycling encompasses any Cycling not done primarily for fitness, Recreation such as cycle touring, or Sport such as cycle ^[21] The Netherlands has been pursuing cycle friendly policies for decades, and around a quarter of their commuting is done by bicycle. Cycling is a very common and popular method of transportation ^[22][23]
  • Telecommuting encouraged through legislation and subsidies. Telecommuting, e-commuting, e-work, telework, working at home (WAH, or working from home (WFH is a work arrangement in ^[24]
  • Online shopping promotion,^[25][26] potentially with automated delivery booths helping to solve the last mile problem and reduce shopping trips made by car. Online shopping is the process consumers go through to purchase products or services over the Internet. Packstation is the name of an automated booth for Package delivery and collection operated by DHL in cities across Germany. The last Mile is the final leg of delivering connectivity from a communications provider to a customer ^[27]

Traffic management

Use of so-called Intelligent transportation system, which guide traffic:

• Traffic reporting, via radio or possibly mobile phones, to advise road users
• Variable message signs installed along the roadway, to advise road users
• Navigation systems, possibly linked up to automatic traffic reporting
• Traffic counters permanently installed, to provide real-time traffic counts
• Automated highway systems, a future idea which could reduce the safe interval between cars (required for braking in emergencies) and increase highway capacity by as much as 100% while increasing travel speeds
• Parking guidance and information systems providing dynamic advice to motorists about free parking

Other associated

• School opening times arranged to avoid peak hour traffic (in some countries, private car school pickup and drop-off traffic are substantial percentages of peak hour traffic)
• Considerate driving behaviour promotion and enforcement. The term intelligent transportation system (ITS refers to efforts to add Information and communications technology to Transport Infrastructure A traffic report is an element of a Radio program or TV news broadcast that informs listeners about general traffic conditions A variable- (also changeable-, electronic-, or dynamic-) message sign, often abbreviated VMS, CMS, or DMS, is An automotive navigation system is a satellite navigation system designed for use in Automobiles. A traffic counter is a device often electronic in nature used to count classify and/or measure the speed of vehicular Traffic passing along a given roadway An automated highway system (AHS or Smart Road is a proposed Intelligent transportation system technology designed to provide for Driverless cars on specific rights-of-way Parking guidance and information ( PGI) systems or car park guidance systems, present drivers with dynamic information on Parking within controlled A school (from Greek σχολεῖον - scholeion) is an Institution designed to allow and encourage Students (or "pupils" Rush hour at Shinjuku 02JPG|thumb|right|250px|Rush hour at Shinjuku Station, Yamanote Line]] A rush hour or peak hour is a part of the day during which Road rage is the behavior by a driver of an automobile or other motor vehicle which thus causes collisions or incidents on roadways Driving practices such as tailgating and frequent lane changes can reduce a road's capacity and exacerbate jams. Tailgating is the practice of driving on a road too closely behind another vehicle such as less than the travel distance in two seconds or equivalently one vehicle-length In some countries signs are placed on highways to raise awareness, while others have introduced legislation against inconsiderate driving.
• Visual barriers to prevent drivers from slowing down out of curiosity (often called "rubbernecking" in the United States). This often includes accidents, with traffic slowing down even on roadsides physically separated from the crash location. This also tends to occur at construction sites, which is why some countries have introduced rules that motorway construction has to occur behind visual barrier
• Speed limit reductions, as practiced on the M25 motorway in London. For a discussion of the maximum speed possible in the universe see Speed of light and Special relativity. To see information about the M25 motorway under construction in Ireland, see N25 road. With lower speeds allowing cars to drive closer together, this increases the capacity of a road. Note that this measure is only effective if the interval between cars is reduced, not the distance itself. With regards to Time, an interval or period is the Duration between two events or occurrences of similar events Low intervals are generally only safe at low speeds.
• Lane splitting/filtering, where space-efficient vehicles, usually motorcycles and scooters, ride or drive in the space between cars, buses, and trucks. Lane splitting is a form of Lane sharing in which the rider of a relatively narrow single-track vehicle (i MotorCycle is the title of a 1993 album by Rock band Daniel Amos, released on BAI Records. This is however illegal in many countries, being perceived as a safety risk. ^[28]

By country

In Brazil

In Brazil the recent records of traffic jams over the major big cities are recognized by public authorities as one of the main challenges for São Paulo, Rio de Janeiro, Belo Horizonte, Brasilia, Curitiba and Porto Alegre, where due to the country's economic bonanza, the automobile fleets have almost doubled in several of these cities from 2000 to 2008. |utc_offset = -2 to -4 |time_zone_DST = BRST |utc_offset_DST = -2 to -5 |cctld São Paulo ( is the largest city in Brazil, with its metropolitan area ranking among the largest urban areas in the world Rio de Janeiro ("River of January" ˈhiw dʒi ʒʌˈnejɾu in Brazilian Portuguese, /ˈriːoʊ di ʒəˈnɛroʊ/ in English is the second largest city of Brazil Belo Horizonte ( Portuguese for "beautiful horizon", (bɛloɾiˈzõtʃi) is the capital of Minas Gerais state located in the Brasília (bɾaˈziliɐ is the Capital of Brazil. The city and its District are located in the Central-West region of the country along a Plateau Curitiba (pron kuɾi'tibɐ or kuɾi'tʃibɐ is the capital City of the Brazilian state of Paraná. Porto Alegre ( is the 10th largest city in Brazil, and the capital city of the Brazilian state of Rio Grande do Sul.

According to Time Magazine, São Paulo has the world's worst traffic jams. Time (trademarked in capitals as TIME) is a weekly American Newsmagazine, similar to Newsweek and São Paulo ( is the largest city in Brazil, with its metropolitan area ranking among the largest urban areas in the world ^[29] In 2008, the accumulated tailbacks have reached in average more than 120 miles (190 km) during rush hours, and on May 9, 2008, the historical record was set with 166 miles (266 km) of accumulated queues out of 522 mi (835 km) being monitored. Events 1457 BC - Battle of Megiddo (15th century BC between Thutmose III and a large Canaanite coalition under the King of 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common ^[30] Despite implementation since 1997 of road space rationing by the last digit of the plate number during rush hours every weekday, traffic in this 20 million city still experiences severe congestion. Road space rationing ( Spanish: Restricción vehicular; Portuguese: Rodízio veicular) is a travel demand management strategy aimed According to experts, this is due to the accelerated rate of motorization occurring since 2003, in São Paulo the fleet is growing at a rate of 7. 5% per year, with almost 1. 000 new cars bought in the city every day, and the limited capacity of public transport. The subway has only 38 miles of lines, though 22 further miles are under construction or planned by 2010. Every day, many citizens spend between three up to four hours behind the wheel.

In New Zealand

New Zealand has followed strongly car-oriented transport policies since after World War II (especially in the Auckland area, where about one-third of the county's population lives),^[31] and currently has one of the highest car-ownership rates per capita in the world, after the United States. The Auckland metropolitan area or Greater Auckland, in the North Island of New Zealand, is the largest and most populous urban area in the country ^[32] As of the negative results, congestion in the big centres is a major problem. Current measures include both the construction of new roading infrastructure as well as increased investment in public transport, which had strongly declined in all cities of the country except Wellington. Wellington (ˈwælɪŋtən is the Capital of New Zealand, the country's second largest urban area, the

In the United Kingdom

In the United Kingdom the inevitability of congestion in some urban road networks has been officially recognised since the Department for Transport set down policies based on the report Traffic in Towns in 1963:

Even when everything that it is possibly to do by way of building new roads and expanding public transport has been done, there would still be, in the absence of deliberate limitation, more cars trying to move into, or within our cities than could possibly be accommodated. The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom, the UK or Britain,is a Sovereign state located In the United Kingdom, the Department for Transport (or DfT) ( Welsh: Adran am Drafnidiaeth) is the government department Traffic in Towns was an influential report and popular book on urban and Transport planning policy produced in 1963 for the UK ^[33].

The Department for Transport sees growing congestion as one of the most serious transport problems facing the UK. ^[34] On 1 December 2006, Rod Eddington published a UK government-sponsored report into the future of Britain's transport infrastructure. Events 800 - Charlemagne judges the accusations against Pope Leo III in the Vatican Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Sir Roderick Ian Eddington (born 1950 Perth, Western Australia) is an Australian businessman The Eddington Transport Study is an examination by Sir Rod Eddington, of the impact of transport decisions on the economy and the environment of the United Kingdom The Eddington Transport Study set out the case for action to improve road and rail networks, as a "crucial enabler of sustained productivity and competitiveness". Eddington has estimated that congestion may cost the economy of England £22 bn a year in lost time by 2025. He warned that roads were in serious danger of becoming so congested that the economy would suffer. ^[35] At the launch of the report Eddington told journalists and transport industry representatives introducing road pricing to encourage drivers to drive less was an "economic no-brainer". Road pricing is an economic concept regarding the various direct charges applied for the use of Roads The road charges includes Fuel taxes licence fees There was, he said "no attractive alternative". It would allegedly cut congestion by half by 2025, and bring benefits to the British economy totalling £28 bn a year. ^[36]

In the United States

In the United States, construction of new highway capacity has not kept pace with increases in population and car use and the resulting increase in demand for highway travel. The United States of America —commonly referred to as the * * * * * * * * * * * * * * * * * * * * * * Before adding any more images to this * * page please do carefully consider * * whether they would be mere decoration * * or actually improve Between 1980 and 1999, the total length of highways as measured by miles increased by only 1. Year 1999 ( MCMXCIX) was a Common year starting on Friday (link will display full 1999 Gregorian calendar) 5 percent, while the total number of miles of vehicle travel increased by 76 percent. ^[37]

The Texas Transportation Institute estimates that in 2000 the 75 largest metropolitan areas experienced 3. The Texas Transportation Institute (TTI in College Station Texas is the largest transportation research agency in the United States 6 billion vehicle-hours of delay, resulting in 5. 7 billion US gallons (21. 6 billion liters) in wasted fuel and $67. 5 billion in lost productivity, or about 0. 7% of the nation's GDP. It also estimates that the annual cost of congestion for each driver is approximately $1,000 in very large cities and $200 in small cities. Traffic congestion is increasing in major cities, and delays are becoming more frequent in smaller cities and rural areas.

In 2005, the three areas in the United States with the highest levels of traffic congestion were Los Angeles, New York and Chicago. The United States of America —commonly referred to as the Los Angeles (lɑˈsændʒələs los ˈaŋxeles in Spanish) is the largest City in the state of California and the American West New York ( is a state in the Mid-Atlantic and Northeastern regions of the United States and is the nation's third most populous Chicago (ʃɪˈkɑːgoʊ is the largest City by population in the state of Illinois and the American Midwest of the United States. The congestions cost for Los Angeles alone was estimated at US$ 9. 325 billion. ^[38]

The issue of wasted fuel and productivity listed by TTI does not address the cost of remedies to congestion. TTI estimates the need of 15,000 lane miles of freeway and major street lane miles just to hold congestion at 2005 levels. Taking into account the costs of the remedies (including construction, maintanence and adminstration) leads to a waste less than a quarter of $67. 5 billion sited by TTI.

Literature

• R. Wiedemann, Simulation des Straßenverkehrsflusses. Schriftenreihe des IfV, 8, 1974. Institut für Verkehrswesen. Universität Karlsruhe. (In German language).
• K. Nagel and M. Schreckenberg. A Cellular Automaton Model for Freeway Traffic. Journal de Physique I, 2:2221-2229, December 1992.
• K. Nagel. High-speed Microsimulations of Traffic Flow. PhD thesis, Universität zu Köln, 1994. [1]
• D. Chowdhury, L. Santen, and A. Schadschneider. Statistical Physics of Vehicular Traffic and Some Related Systems. Phys. Rep. , 329:199-329, 2000. [2]
• D. Helbing. Traffic and related self-driven many-particle systems. Rev. Mod. Phys. , 73(4):1067-1141, 2001. [3]

See also

• Congestion pricing, a road pricing option for curbing demand. Congestion pricing or congestion charges is a system of surcharging users of a Transport network in periods of peak Demand to reduce Traffic congestion
• Gridlock, total standstill of traffic
• Traffic flow, the mathematical study of traffic flows
• Transims
• Transportation Demand Management, operational solutions
• Transportation forecasting

References

External links

• Institute of Transportation Engineers
• How Traffic Works from HowStuffWorks.com
• The New Mobility Agenda
• Traffic Bulldog - Commuter Advocacy
• Anatomy of a traffic jam (entry explaining a type of traffic jam from a private blog)

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