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Controlled Access

Controlled access

.]] A freeway (also superhighway, expressway or motorway as further explained below) is a multi-lane highway (road) designed for high-speed travel by large numbers of vehicles, and having no traffic lights, stop signs, nor other regulations requiring vehicles to stop for cross-traffic.

In general

Design features

Freeways have high speed limits and multiple lanes for travel in each direction. The number of lanes may vary from four or six in rural areas to as high as sixteen or eighteen in certain global cities. A median (originally "medial strip") or central reservation separates the lanes travelling in opposite directions. Separation may be achieved through distance or through the use of high crash barriers like cable barriers and Jersey barriers. Crossroads are bypassed by grade (height) separation using underpasses and overpasses. In addition to the sidewalks attached to roads that go over or under a freeway, most countries also provide specialized pedestrian bridges and underground tunnels. Such structures enable pedestrians and cyclists to cross the freeway without having to make a long detour to the nearest road for which a grade separation has been provided. Freeway entrances and exits are limited in number, and are designed with special onramps and offramps, so as to ensure that vehicles do not disrupt the main flow of traffic as they enter or leave the freeway. In some countries, the exits are numbered. Exit numbering may be by mile or kilometre, or in a simple sequential fashion. Where freeways cross, engineers provide interchanges with elaborate ramp systems that allow for smooth, uninterrupted transitions between all through routes (as funds permit). Because the high speeds reduce decision time, freeways usually have more traffic signs than the equivalent signs on most highways and roads; the signs are often also larger. In major cities, especially on freeways six lanes in width or wider, guide signs are mounted on overpasses or overhead gantries so that drivers can see where each lane goes. Some countries prefer to use a special icon for freeways, while others simply post "Freeway Entrance" and "Begin Freeway" signs. Another common problem with freeways is that it is nearly impossible to avoid wrong-way drivers, and the subsequent head-on collisions are often fatal. Therefore, special signage and lane markings are used to discourage drivers from going the wrong way. Freeways do not usually have traffic lights, but expressways may, in places where this distinction is made.

Gallery of design features

Signage for entering the freeway

Image:Beginfreewaysign.jpg|American "begin freeway" sign Image:Freewayentrancesign.jpg|American on-ramp sign Image:Autorouteentrancesign.jpg|European on-ramp and "begin freeway" sign

Signage for leaving the freeway

Image:Endfreewaysign.jpg|American "End Freeway" warning sign Image:SR 429 north exit 33.jpg|American numbered exit off-ramp sign Image:Autorouteexitsign.jpg|French end of freeway/off-ramp sign

Signage for finding one's way

Image:Americanguidesignage.jpg|American guide signs Image:Americanexitguidesign.jpg|American numbered exit guide sign Image:Quebec exit number.jpg|Canadian guide signs Image:PRC Expressway.jpg|Chinese guide signs Image:SILKhighway.jpg|Malaysian guide signs Image:Europeanguidesignage.jpg|Swiss guide signs Image:AutopistaVespucioSurantesdeRuta5.JPG|Chilean guide signs Image:On the Dhahran-Al Khobar Highway.jpg|Saudi Arabian guide signs

Grade separations

Image:Sandhillroadoverpass.jpg|American freeway overpass

Measures to prevent wrong way drivers

Image:Californiaofframpwrongwaysignage.jpg|Used by some U.S. states at freeway ends and off-ramps

Access restrictions

To minimize accidents, access to freeways is usually limited to vehicles capable of consistently maintaining a high speed, like automobiles, trucks, motorcycles, vans, and buses. Pedestrians, bicyclists, slow-moving vehicles, horses, horse-drawn vehicles, and anything else that might obstruct fast-moving vehicles are all prohibited; however some freeways allow non-motor vehicles (e.g., bicycles) (see non-motorized vehicle access on freeways for more info).

Ancillary facilities

In most parts of the world, there are public rest areas on freeways and expressways as well as other types of highways. In some U.S. states, public rest areas are located almost exclusively on freeways or expressways (since only those routes carry the high traffic necessary to justify the area's maintenance cost).

Nomenclature

Worldwide

Freeway is the term used in most of the United States, parts of Canada, and parts of Australia, notably Victoria, South Australia and Western Australia; the United Kingdom, Republic of Ireland, the rest of Australia and other Commonwealth countries prefer motorway, most of Canada uses expressway, while the province of Québec uses Autoroute; Autoroute is also used in France and other francophone countries; Mexico and other Spanish-speaking countries use the term Autopista; the German-speaking world uses Autobahn, the Dutch-speaking world uses autosnelweg, Italy, Poland and Romania use autostrada; and China and Japan use the term expressway, although they once used freeway. Croatia uses Autocesta, Slovakia uses diaľnica and Czech republic uses dálnice. Some RIRO expressways may have at-grade intersections. Some commentators consider them to be freeways because they have design speeds of 65 mph or higher. However, others argue that RIRO expressways lack complete-controlled access since existing private businesses are allowed to retain their entrances and thus should not be classified as full/true freeways.

United States

The United States definition, as accepted by civil engineers, is that an expressway is any highway to which adjoining property owners do not have a legal right of access. A freeway is an expressway which is free-flowing; that is to say, there are no traffic conflicts on the main line of the highway which must be mediated by a traffic signal, stop signs, or related traffic controls. Another way to look at it is that an expressway is limited-access, and a freeway is controlled-access, but this distinction is not universally accepted. Many non-engineers misapprehend the "free" in "freeway" to mean that such a highway must be free of charge to use. In some states, like California, the vast majority of freeways are toll-free (except where they cross an occasional toll bridge), while other states like Illinois and Florida have toll plazas at every exit on certain expressways. In the U.S., the terms expressway and freeway are legally defined by federal regulation and the laws of most states in accordance with the civil engineering usage just described. However, the distinction between these two terms is not universal, and in several states which built freeways very early on (including Connecticut, Illinois, Massachusetts, New Jersey, New York, Pennsylvania, and Rhode Island), the terms expressway and freeway have the same meaning, and usually expressway or just highway, an older usage, is preferred. In New Jersey and Pennsylvania, newer roads are often officially styled freeways, where older roads retain the title expressway. These are also states which have toll roads, and therefore the distinction is made between a tollway (or turnpike) and a freeway, the latter not costing toll. According to people from these states, an "expressway" is the general category, and then, depending on whether the expressway is toll or free, it may be either a tollway or a freeway. Frequently, in the Midwest and the South, neither "freeway" nor "expressway" is commonly used, and the preferred term is "interstate," even in cases where the expressway might not have been designated an Interstate Highway. In the rest of the country, freeway is the usual term; however, the distinction between freeways and expressways is not always as clear or well-understood as it is in California, which has many of both kinds of highway. Florida has different definitions for both "expressway" and "freeway" than other states. In Florida, an "expressway" is defined as a limited-access toll road, while a "freeway" is any other limited- or controlled-access road which costs no money to travel on.

Canada

In Ontario, while the definitions of "freeway" and "expressway" are consistent with that of the US, "highway" is used far more often than freeway, especially inside the Greater Toronto Area. While this has caused some confusion because the province applies "highway" (The King's Highway) to principal roads in its network, whether freeway or non-freeway, it is usually resolved simply by using the 400-series number to distinguish the freeway. Nonetheless, outside of the GTA, the 400-series numbering does not entirely solve the problem as there are non 400-series freeways built to similar standards such as the Conestoga Parkway (which includes sections of Highways 7, 8 and 85, including a long 7/8 multiplex). The only freeway officially labelled as such is the Macdonald-Cartier Freeway but it is usually known as Highway 401 or "the 401". In Toronto, Ontario, several roads labelled "expressways" in the municipal network are actually fully controlled-access freeways such as the Gardiner Expressway and Spadina Expressway (later renamed Allen Road). Other provinces use varying rules in their official road designations. Alberta and British Columbia have spent millions of dollars investing to make highways into freeways. In Alberta, the main freeway is the Queen Elizabeth II Highway running between Edmonton and Calgary. The road is a freeway through the city of Calgary. Edmonton, however, has many interchanges in progress. On the Trans-Canada Highway west of Calgary, it is a freeway up until the town of Lake Louise. In British Columbia, the main freeways are BC provincial highways 1, 5, and 99.

Construction issues

Freeways have been constructed both between urban centres and within them, making common the style of sprawling suburban development found near most modern cities. As well as reducing travel times, the ease of driving on them reduces accident rates, though the speeds involved also tend to increase the severity and death rate of the collisions (or crashes) that do still happen.

Frontage roads

crash (seen here near Berkeley, California). The frontage road on the far right typically becomes just as congested as the main freeway.]] Because abutters do not have the right of access that they would have for an ordinary public road, the authority undertaking construction of a freeway is frequently required to provide alternate means of access to those landowners. This is frequently accomplished, in areas lacking a dense surface street network, by construction of two uncontrolled roads parallel to and on either side of the freeway, known as frontage roads. These often are designed with one-way traffic flow, but not always. In Texas, where this pattern is perhaps at its zenith, such roads are frequently constructed in anticipation of a future freeway corridor, as many as ten years in advance, in order to influence development patterns on the adjoining land. Frontage roads are also often constructed in more densely-developed areas as a means to provide convenient direct access to and from the parallel freeway while minimizing the need for interchanges at every major cross street. However, some traffic studies have indicated that this particular type of access and the development that ensues generally causes significant traffic congestion and disrupts flows along major freeways. These studies prompted concern for TxDOT, which formally adopted a major shift in frontage road [http://www.abilenetx.com/comp/www.abilenecompplan.com/abilene_comp/documentframeset3fcd.html?docname=http://www.abilenecompplan.com:80/abilene_comp/docs/FrontageRoad.pdf policy] (2002) by stating that no new frontage roads will be built along any proposed limited-access freeways, thus ending a long-standing pattern of freeway-induced development in Texas. Access issues will continue to be assessed on a local basis, and frontage roads could still be constructed if warranted by traffic studies.

Collector lanes

The successor to frontage/service roads in urban freeways is the collector-express system; the lanes accessing (often closely-spaced) interchange ramps are known as collector/distributor roads. Newer suburban freeways are designed with interchanges spaced far apart such that neither service roads or collector lanes are needed.

History

The concept of limited-access automobile highways dates back to the New York City area Parkway system, which began to be constructed in 1907–1908. Designers elsewhere also researched these ideas, especially in Germany, where the Autobahn became the first national freeway system. The term "freeway" first surfaced in the mid-1930s in proposals for the improvement of the New York City parkway network. However, the first true freeway in the United States is generally considered to be the Pennsylvania Turnpike, which opened on October 1, 1940. The Turnpike was so advanced for its time that tourists even had picnics in the median (that is, after it was already open to traffic) and local entrepreneurs did a brisk business in souvenirs. It was designed so that straightaways could handle maximum speeds of 102 miles per hour, and curves could be taken as fast as 90. Shortly thereafter, on December 30, 1940, California opened its first freeway, the Arroyo Seco Parkway (now called the Pasadena Freeway) which connected Pasadena with Los Angeles. And in 1944, Michigan opened its first freeway, the Davison Freeway, within Detroit. Meanwhile, traffic in Los Angeles continued to deteriorate and local officials began planning the huge freeway network for which the city is now famous. Today, many freeways in the United States belong to the extensive Interstate highway system (most of which was completed between 1960 and 1990). Almost all interstates are freeways, but the earlier United States highway system and the highway systems of U.S. states also have many sections that are limited-access (though these systems are mostly composed of uncontrolled roads). Only a handful of sections of the Interstate system are not freeways, such as I-81 as it crosses the American span of the 2-lane Thousand Islands Bridge.

Controversy

I-81, downtown Houston.]] Freeways have been heavily criticized by environmentalists and preservationists for the noise, pollution, and economic shifts they bring. Additionally, they have also been criticized by the driving public for the inefficiency with which they handle peak hour traffic. Often, rural freeways open up vast areas to economic development, generally raising property values. But mature freeways in urban areas are quite often a source of lowered property values, contributing to the deleterious effects of urban blight. One major problem is that even with overpasses and underpasses, freeways tend to divide neighborhoods — especially impoverished ones where residents are less likely to own a car that could easily take them around the freeway. For these reasons, almost no new urban freeways have been built in the U.S. since 1970. Some have even been demolished and reclaimed as boulevards, notably in San Francisco (Embarcadero Freeway) and Milwaukee (Park East Freeway). Some argue that freeway expansion is self-defeating, in that expansion will just generate more traffic. That is, even if traffic congestion is initially shifted from local streets to a new or widened freeway, people will begin to run errands and commutes to more remote locations which took too long to reach in the past. Over time, the freeway and its environs will become congested again as both the average number and distance of trips increase. This is the debated induced demand hypothesis. Pro-freeway advocates point out that properly designed and maintained freeways are aesthetically pleasing, convenient, and safe, at least in comparison to the uncontrolled roads they replace or supplement. Freeways expand recreation, employment and education opportunities for individuals and open new markets to small businesses. And for many, uncongested freeways are fun to drive. Another common argument is that public transit has often failed to relieve traffic congestion, due to the current trend of increasing private car ownership as family wealth levels increase. Public transit projects are just as costly as building freeways, and may constitute an inefficient use of public funds that could have been used more effectively for acquiring right-of-way and building more freeways. Finally, constructing new freeways in built-up urban areas could divert cars away from local city streets, and in turn might make communities safer. The closure of an existing urban freeway (or the imposition of tolls) could simply force traffic back onto local streets, instead of making it disappear. However, some studies [http://www.pednet.org/artNotEaseCongestion.html] have shown that the removal of urban freeways actually reduce traffic congestion by causing people to find alternate routes, use mass transit or simply reduce driving altogether. At present, freeway expansion has largely stalled in the United States, due to a multitude of factors that converged in the 1970s: higher due process requirements prior to taking of private property, increasing land values, increasing costs for construction materials, local opposition to new freeways in urban cores, the passage of the National Environmental Policy Act (which imposed the requirement that each new project must have an environmental impact statement or report), and falling gas tax revenues as a result of the nature of the flat-cent tax (it is not automatically adjusted for inflation) and the tax revolt movement. Dramatic improvements in vehicle gas mileage have also reduced gas tax revenues.

Recent developments

Outside the U.S., many countries continue to rapidly expand their freeway networks. Examples include: Australia, Canada, Chile, China, France, India, Israel, Mexico, Malaysia and Taiwan. Australia and France in particular have been innovative in using the newest tunneling technologies to bring freeways into high-density downtowns (Sydney and Melbourne) and historic rural areas (Versailles). China already has the world's second largest freeway network in terms of total kilometers and will probably overtake the U.S. well before the end of the 21st century (those road expansion plans do not account for finite oil supplies). A recent freeway expansion is the North Luzon Expressway in the Philippines, expanded in February 2005, which has the quality of a modern french tollway. In Australia, the city of Adelaide pioneered the concept of a dedicated reversible freeway. The M2 expressway runs toward the city in the morning and out of the city in the evening. Its ramps are designed so that they can double as on- or off-ramps, depending upon the time of day. Gates and electronic signage prevent motorists from driving in the wrong direction. Meanwhile, major progress has been made in making existing U.S. freeways and expressways more efficient. Experiments include the addition of high-occupancy vehicle lanes (HOV lanes) to discourage driving solo, and building new roads with train tracks down the median (or overhead). California's Caltrans has been very innovative in squeezing HOVs into limited right-of-way (by elevating them), and in building special HOV-only ramps so that HOVs can switch freeways or exit the freeway without having to merge across regular traffic. Many states have added truck-only ramps or lanes on heavily congested routes, so that cars need not weave around slow-moving big rigs. Intelligent transportation systems (ITS) are also increasingly used, with cameras to monitor and direct traffic, so that police, fire, ambulance, tow, or other assistance vehicles can be dispatched as soon as there is a problem, and to warn drivers via variable message signs, radio, television, and the web to avoid problem areas. Research has been underway for many years on how to partly automate cars by making smart roads with such things as buried magnets to guide sensor-equipped vehicles, with on-board GPS to determine location, direction, and destination. While these systems may eventually be used on surface streets as well, they are most practical in a freeway setting. In the United States, a few short privatized tolled freeways have also been built by private companies with mixed success.

Freeways around the world

Image:freeway.jpg|Interstate 405 in Irvine, California, with an interchange in the foreground Image:TullamarineFwy.jpg|The "Sound Tube", CityLink Freeway, Melbourne, Victoria, Australia. Image:Autopista-Central-2.jpg|Autopista Central, Santiago, Chile. Image:AutopistaLibertadores.JPG|Autopista Los Libertadores, (International Freeway) Santiago, Chile Image:DSCN4922.JPG|US-75 Central Expressway southbound in Dallas,Texas Image:376 east.jpg|Interstate 376 eastbound in downtown Pittsburgh Image:Swedish_Motorway_Varberg.jpg|Europeway E6 E20 in southwest Sweden in Varberg

References

Anonymous. "Median barriers prove their worth." Public Works 123, no. 3 (March 1992): 72-73. Bernstein, Victor H. "Safer Motor Roads: New Construction Principles Introduced On Modern Highways To Cut Accidents." New York Times, 1 December 1935, p. 21. Cervero, Robert. "Road expansion, urban growth, and induced travel: a path analysis." Journal of the American Planning Association 69, no. 2 (Spring 2003): 145-164. Coulombe, Gerard. "Doing The Turnpike Crawl." New York Times, 6 July 1986, sec. CN, p. 16. Hill, Gladwin. "Traffic Chaos Spurs Los Angeles To Plan 'Freeways' On Mass Scale: Coast Metropolis, Lacking Rapid Transit System Such as New York Possesses, Maps $300,000,000 Highway Set-Up." New York Times, 13 January 1947, p. 12. Martin, Hugo. "Will More Freeways Bring More Traffic?" Los Angeles Times, 10 April 2002, sec. B, p. 1. McCreery, Sandy. "Don't just sit there, enjoy it!" New Statesman, 23 July 2001, 23. Section 1A.13, Manual on Uniform Traffic Control Devices, 2003 ed. [http://mutcd.fhwa.dot.gov/HTM/2003r1/part1/part1a.htm] Patton, Phil. "A quick way from here to there was also a frolic." Smithsonian 21, no. 7 (October 1990): 96-108. Spivak, Jeffrey. "Today's road opening represents progress, pain." Kansas City Star, 27 July 1999, sec. A, p. 1. Taylor, Brian D. "Public perceptions, fiscal realities, and freeway planning: the California case." Journal of the American Planning Association 61, no. 1 (Winter 1995): 43-59. Van Hengel, Drusilla, Joseph DiMento, and Sherry Ryan. "Equal Access? Travel Behaviour Change in the Century Freeway Corridor, Los Angeles." Urban Studies 36, no. 1 (March 1999): 547. Yordan, E.L. "The 'Freeway' System Expands: Broader Roads With Grade Crossings Eliminated Are Built And Latest Designs Envision Still Greater Speed And Safety." New York Times, 24 February 1935, p. 21.

External links

- [http://www.georgianavigator.com Georgia NaviGAtor] - example of a freeway information system
- [http://www.archenzo.it A new concept in motorway design - Rethink the highways] ja:高速道路 ko:고속도로 zh-cn:高速公路 Category:Road infrastructure Category:Road transport __NOTOC__

Motorway

A motorway (in the United Kingdom, Ireland, New Zealand and some Commonwealth nations) is both a type of road and a classification. Motorways are highways designed to carry a large volume of traffic where a normal road would not suffice or would be unsafe, usually between cities. In the UK they are predominantly dual-carriageway roads, usually with three lanes in each direction, although four-lane and two-lane carriageways are also common, and all have grade-separated access. Equivalent terms in other countries include autoroute, Autobahn, freeway, autostrada, autopista, motorvej,autópálya, motorväg and autoput.

Regulations

autoput ]] For a road to be classified as motorway a number of conditions must be fulfilled. The following conditions generally apply:
- Motorways must be accessed at junctions by slip roads off the sides of the main carriageway;
- Separate motorways are joined by link-roads at an interchange, the object of which is to allow traffic to change route without stopping or slowing significantly;
- Traffic lights are not permitted (except at toll booths and certain small interchanges);
- The start and end of a motorway must have signposted entry and exit points;
- Certain types of transport are banned, typically pedestrians, bicycles, learner drivers, horses, agricultural vehicles, underpowered vehicles (e.g. small scooters, invalid carriages). In the UK and the Republic of Ireland there are further restrictions:
- The central reservation must remain unbroken (an exception being the Aston Expressway in Birmingham, which has none);
- Emergency phones must be provided at a regular distance;
- A 'minimum speed limit' may apply. Note that these only apply to roads directly designated as motorways. Roads may also be indirectly designated as such, see #Inheritance below. The construction and surfacing of motorways is generally of a higher standard than conventional roads, and maintenance is carried out more frequently; in particular, motorways drain water very quickly to reduce hydroplaning. Many roads are of near-motorway quality, but are not classified as such (generally for breaking one or more of the above rules). These are referred to as dual carriageways, which in Britain usually have the same 70 mph (110 km/h) limit (the limit in Ireland and New Zealand is the regular 100 km/h (65 mph) limit). They may be subject to a lower speed limit (e.g. in urban areas). hydroplaning]] In Ireland and the UK, motorways are denoted by blue signage and an M-prefixed or suffixed road number. Speed limits are generally higher than on ordinary roads, with an overall limit of 70 mph (110 km/h) for cars in the UK. Some types of vehicle may be subject to a lower limit, while often sections of motorway are subject to lower speed limits due to local driving conditions. Lanes closest to the edge of the road are intended for general driving – these are hence the "inside" lanes, while the lanes closest to the median are intended for overtaking (passing) slower-moving vehicles – hence they are termed "outside" lanes. Some vehicles, notably heavy goods vehicles, are not permitted to use the rightmost lane on a three (or more) lane motorway. Roads in the Republic of Ireland have had metric speed limits since 20 January 2005 to conform to European convention and to existing directional signage, which has long shown metric distances. The new speed limit introduced for motorways is 120 km/h (75 mph). In New Zealand motorways were historically distinguished from other roads with green signage. This changed with the establishment of Transit New Zealand which extended the use of green signs to the entire state highway network. The speed limit on motorways is fixed at the top limit for state highways, 100 km/h (65 mph). This rule is most in evidence in Wellington where Centennial Highway in the Ngauranga Gorge is not designated as a motorway because of the steep gradient, general usage and slow-speed junctions, despite leading directly into the Johnsonville-Porirua motorway. The Conservative Party had proposed increasing the UK motorway speed limit to 80 mph (130 km/h), should they gained power at the past election. Many road safety groups feel this would be a good idea, as it more closely represents the normal (and, they claim, safe) driving practice of the majority of motorway users. As in Germany but unlike in some other countries, drivers are not permitted to pass on an inside lane (a lane further from the median) unless traffic in the 'faster' lanes is stationary. With a touch of black humour, the practice is popularly known as undertaking.

Features

black humour The road surface is generally asphalt ('black top') or concrete ('white top'). White dashed lines denote the lane separation, while an unbroken white line is painted alongside the median (usually known as the 'central reservation'). A white line (or in the Republic of Ireland, a yellow line) on the edge of the slow lane marks the edge of the hard shoulder. The hard shoulder is not used for traffic and is reserved for breakdowns or emergency maneuvers. Generally lanes closer to the centre of the road (outer lanes) are used for overtaking, while lanes near the edge of the road (inner lanes) are used for slower traffic (see diagram on right), as in the UK it is illegal to overtake on the left (commonly known as undertaking) except in emergencies, when signs indicate drivers may do so, or when traffic is moving slowly. Traffic should always use the lefthandmost lane possible. Generally this means a vehicle should use the lefthand lane next to the hard shoulder, and use the other two lanes only for overtaking manouvers, moving back into the left lane once they have passed the slower vehicle(s). In heavy traffic, it is acceptable to cruise in the middle lane to pass slower vehicles to avoid constant lane changes. A significant problem on motorways is the 'middle lane hog', a driver who drives in the middle lane when there is no reason to do so. This can be very frustrating for other drivers. Faster vehicles approaching in the left hand lane have to manouver across four lanes of the motorway rather than two to pass such a vehicle, since undertaking is forbidden. Drivers of heavy goods vehicles can be especially frustrated by a middle lane hog, as their vehicles are not permitted to use the righthandmost lane under normal circumstances. Since undertaking is forbidden, a heavy goods vehicle cannot legally pass a slower moving vehicle in the centre lane. In the UK lanes in a given direction are numbered from left to right as lane 1, lane 2, lane 3, etc. Lane 1 is the lane next to the hard shoulder. Other features are crash barriers, cat's eyes and increasingly, textured road markings (a similar concept to rumble-strips). In the UK it is a requirement that all motorways have emergency telephones at regular (usually one-mile) intervals, which connect directly to the police. The most basic motorway junction is a two-lane flyover with four slip-roads, two on each side of the motorway, to exit or enter. A simple crossroads or roundabout is present on either end of the flyover. A rather large version of a roundabout, using two curved flyovers is sometimes used to present a single large junction for users of the slip-roads or crossing road. The slip roads leading off the motorway are known as 'exit sliproads', those leading onto the motorway as 'entry sliproads'. The precise sliproad at any junction may be identified by reference to the direction of the carriageway, for example 'northbound entry slip'. An Irish invention is the signal-controlled roundabout which is often used in these situations. A further degree of complexity is present in Britain with varying types of Spaghetti Junction-style interchanges.

Location and construction

Major intercity or national routes are often built or upgraded to motorway standard. Motorways are also commonly used for ring roads around cities or bypasses of built-up areas. Examples of ring-road motorways are the M25 around London and the M50 around Dublin. In Britain there are plans to improve many motorways as well as to upgrade some roads to motorway status. In the Republic of Ireland, the National Roads Authority has been connecting main cities with motorways as part of a six-year National Development Plan. The European Union has part-funded many motorway projects in the past, as part of a Trans-European Transport Networks, and there are plans to invest billions of euro in such projects in the next ten years. euro] The newest UK motorway is the M6 Toll, bypassing Birmingham and Wolverhampton, which opened in 2004 and is the only completely toll motorway in England. There are tolled sections of motorway on the M4 and M48, where they cross the the River Severn at the Severn crossings.

Inheritance

In the UK, certain types of traffic are not permitted on motorways. Thus, to avoid people being forced to travel illegally, there are a number of rules about stretches of road which must be designated as motorways. In all cases, there must be an escape route for traffic not wishing or not permitted to enter the motorway. As a result, the motorway technically begins as soon as the escape route has diverged from it; for example at a grade-separated junction, the motorway starts at the junction with the exiting slip road, and the opposite slip road is also part of the motorway for this and the following reason. The exception was the A1(M) near Leeds, which was "illegal", as pedestrians could legally cross 300 yards from the start, but cyclists and other types of traffic not permitted on motorways had no way of turning back. The escape route was the Boot & Shoe a mile before. This is remedied by the A1(M) extension. As a result, this creates a less-restrictive set of rules for the standard of the road. Roads whose only destination is a motorway must be assigned motorway status, notwithstanding the possibility of them not being built to normal motorway standards. For example, the A48(M) motorway outside Cardiff begins after the last exit to St Mellons, since by staying on the dual carriageway you cannot get anywhere other than the M4 eastbound; however, the A48(M) is a motorway-grade highway. On the other hand, there are roads such as the A6144(M), a 1.2 mi (2 km) long single-carriageway road, which are classified as such since they lead inescapably to the motorway (in this case, the M60).

Route numbering

In the United Kingdom, motorways sometimes adopt the number of the nearest "A" road heading in broadly the same direction. However this is just for convenience, and about half of motorways don't bypass the A road with the same number - Motorways follow their own zonal pattern, similar to the A+B road zones, but with the boundarys formed by the 1-digit motorways (and various A roads where there are gaps), as opposed to the one-digit A roads (NB, the 4 zone seems to be hourglass shaped and motorways west of the M5 but south of the M4 have 4-zone numbers). The A road usually continues to also use that number, thus allowing both an "A1" road and "M1" motorway to exist as full complementary routes. In the Republic of Ireland, motorway and national route numbering does not follow the same convention. As of 2005, all motorways in the Republic are part of, or form, National Primary Routes. These routes are numbered in series, using numbers from 1 to 33 (and separately from the series - 50), which apart from on motorways, carry an "N" prefix. In the Republic of Ireland, motorways use this route number (of the national route they form part of) with an M prefix rather than N. In most cases, the motorway has been built as a bypass of a road previously forming the national route (e.g. M7 bypassing roads previously forming the N7) - the bypassed roads are reclassified as Regional Roads, although updated signposting may not be provided for some time, and adherence to signage colour conventions is lax (regional roads have black-on-white directional signage, national routes use white-on-green). The M50, an entirely new national route, is an exception to the normal inheritance process - as it does not replace a road previously carrying an "N" number. The M50 was nevertheless legislated as the "N50" route (despite having no non-motorway sections). The M50's designation was chosen as a recognisable unique number (As of 2005 N34 is the next unused National Primary Route designation).

External links

- [http://www.dft.gov.uk/ Department for Transport] (United Kingdom)
- [http://www.nra.ie/ National Roads Authority] (Republic of Ireland)
- [http://www.europa.eu.int/comm/transport/index_en.html European Union Transport Policy]
- [http://www.cbrd.co.uk/motorway/ CBRD Motorway Database]
- [http://www.uk-roads.org.uk/ UK Roads Portal]
- [http://pathetic.org.uk/ Pathetic Motorways]
- [http://www.learn2live.co.uk/ Learn-2-Live Campaign] for compulsory motorway tuition for every newly qualified driver
- [http://web.tiscali.it/archenzo/motorway/enmotor_way.html New concept in motorway design]
- of "inheriting" motorway status - the A6 road between the Tramway Lane roundabout and the M61/M65 junction. (Zoom out to see it in motorway colour.) Category:Road infrastructure Category:Road transport Category:Transportation in Europe Category:Rights of way ja:高速道路 zh-cn:高速公路

Highway

:For other uses, see Highway (disambiguation). A highway is a major road within a city, or linking several cities together. It includes roads known as interstate highway, freeway, motorway and autobahn, where a full description varies by country. Generally, a highway is a road which has multiple lanes of traffic in each direction, often with a physical division (median) between opposing traffic, and separate access ramps to and from the highway which are more widely separated than connections on a standard road and are often grade-separated. A highway may prohibit access by pedestrians and limit what vehicles may travel on it. Historically, a highway was any major road travelling a long distance outside of a city. Early roads between cities would sometimes suffer from highwaymen who would rob people travelling the route. In the 20th century, however, the word generally came to be used only for high-speed, often specially-designed automobile routes. On 10 September, 1913 the first paved coast-to-coast highway opened in the US. Highways usually have a higher speed limit than other roads because they have additional lanes and are designed for driving at a higher speed. In remote areas, a highway may have rest areas where motorists may stop and relax before resuming a long drive. By convention, the lane nearest the median on a multi-lane highway is called the passing lane. The United States has a vast network of national highways (Interstate highways) linking the different U.S. states together, as does Australia albeit on a much smaller scale and mostly concentrated on the southeast coastline. Some highways, like the Pan-American Highway or the European routes, bridge multiple countries. With the latter a single road may have several national designations in addition to the European one. Probably the most famous highway in the United States is Route 66, as immortalised in the song "(Get Your Kicks On) Route 66", while if one follows Australia's Highway 1 the driver can travel from state capital to state capital, almost the entire way around the whole country. The longest single national highway in the world is the Trans Canada Highway, which runs from Victoria, British Columbia, on the Pacific Coast, through ten provinces to the Atlantic Coast, at St. John's, Newfoundland.

Nomenclature

The terms used for various types of highways such as freeway, expressway, motorway and autobahn, vary between countries or even regions within a country. In some places a highway is a specific type of major road that is distinct from freeway or expressway; in other places the terms may overlap. In law highway may mean any public road or canal. However, in some countries, the term highway is not generally used at all.

Australia

In Australia, a highway is a distinct type of road from freeways and motorways. The word highway is generally used to mean major roads connecting large cities, towns and different parts of metropolitan areas. Metropolitan highways often have traffic lights at intersections, and rural highways usually have only one lane in each direction. The words freeway or motorway are generally reserved for the most arterial routes, almost always with no traffic light intersections and usually significantly straightened and widened. The term motorway is used in some Australian cities to refer to freeways that have been allocated a metropolitan route number, and in Sydney, a motorway has a toll, whereas a freeway is free of charge. It is now possible to travel from Melbourne to Sydney without having to stop at a traffic light. Roads may be part-highway and part-freeway until they are fully upgraded.

New Zealand

In New Zealand, a motorway runs through urban areas and an expressway runs through rural areas. Both motorways and expressways generally have no access to adjacent properties and no facility for pedestrians or cyclists. New Zealand's main routes are designated state highways. State Highway 1 is the only route to run through both the North and South Islands, and runs (in order north-south) from Cape Reinga to Wellington in the North Island, and from Picton to Bluff in the South Island. State Highways 2-5 are main routes in the North Island, State Highways 6-9 in the South Island, and state highways numbered from 10 onwards are generally found in numerical order from north to south. State highways usually incorporate different types of roads, for example, State Highway 1 from Auckland to Hamilton incorporates the Northern and Southern Motorways in the Auckland area, the Waikato Expressway, and a rural road before passing through the streets of Hamilton. The term freeway is rarely used relating to New Zealand roads, and can only be considered an Americanism.

Brazil

In Brazil, highways (or expressway/freeway) are named "rodovia", and Brazilian highways are divided in two types: regional highways (generally of less importance and entirely inside of one state) and national highways (of major importance to the country). In Brazil, rodovia is the name given exclusively to roads connecting two or more cities with a sizable distance separating the extremes of the highway. Urban highways for commuting are uncommon in Brazil, and when they are present, they receive different names, depending of the region (Avenida, Marginal, Linha, Via, Eixo, etc). Very rarely names other than "rodovia" are used. Regional highways are named YY-XXX, where YY is the abbreviation of the state where the highway is running in and XXX is a number (e.g. SP-280; where SP means that the highway is running entirely in the state of São Paulo). National highways are named BR-XXX. National highways connects multiples states altogether, are of major importance to the national economy and/or connects Brazil to another country. The meaning of the numbers are:
- 001-100 - it means that the highway runs radially from Brasília. It is an exception to the cases below.
- 101-200 - it means that the highway runs in a south-north way.
- 201-300 - it means that the highway runs in a west-east way
- 301-400 - it means that the highway runs in a diagonal way (northwest-southeast, for example)
- 400-499 - another exception, they are less important highways and its function is to connect a city to an arterial highway nearby Often Brazilian highways receives names (famous people, etc), but even though, they continue to have a YY/BR-XXX name (example: Rodovia Castelo Branco is also SP-280). See List of Brazilian Highways

Canada

- In Canada, there is no national standard for nomenclature, although highway appears more popular in all areas except
- Ontario: highways are called expressway or 400-Series; 401 in Toronto is a freeway. The DVP (Don Valley)is a parkway. All provincial managed highways are called King's Highways. Highway 407 is a toll route.
- Quebec where highways are called autoroutes (borrowing the term from French).
- Nova Scotia numbers its freeways by the routes they parallel, for example, Highway 101 parallels Trunk 1.
- The Trans Canada Highway, the highway (mostly four lane, sometimes less, sometime more) that crosses the entire country (and entering all ten provinces), holds the record as the longest national highway in the world. The only portions of this road not considered to be of freeway status are in the British Columbia Rocky Mountains, Northern Ontario, and in Newfoundland.

China

"Highways" in China, more often than not, refer to China National Highways. The multi-lane, central-separation routes are instead called expressways. In Mainland China, private companies reimbursed through tolls are the primary means of creating and financing the National Trunk Highway System. There is actually no separate classification for expressway (which is the term more often used in the PRC). Most likely, they are lumped with first-grade guodaos (meaning National roads). Beneath guodaos in rank level are shengdaos (provincial roads) and xiandaos (pronounced hsien-daos or shien-daos, which equate to county-level roads). Some expressways are numbered with a leading zero (e.g. G030). Freeway was used on a few expressways (such as the Jingshi Freeway) before expressway was chosen as a standarised term. The Chinese name for expressways (or freeways, as they used to be called) is uniform; in pinyin, it is gao su gong lu, which literally means "high speed public road". In the mainland of the PRC, highway does not refer to a freeway or expressway, but instead to a normal road equivalent to an "A"-level road in Britain, or a class-one non-expressway. This can cause some confusion, though. public road, New Territories, Hong Kong.]]

Hong Kong

In Hong Kong, the type of high speed roads is referred to as expressway, but some are named as highways or roads ('Yuen Long Highway', 'Tolo Highway', 'Tsuen Wan Road', 'Tuen Mun Road', etc.). Some others are named corridors and bypasses.

India

Main article Indian highways In India, 'Highway' refers to one of the many National Highways that run up to a total length of about 58000 kilometers. An expressway refers to any elevated road with grade-separated intersections.

Malaysia

The highest level of major roads in Malaysia, expressway (lebuhraya), has full access control, grade separated junctions, and mostly tolled. The expressways link the major state capitals in Peninsular Malaysia and major cities in Klang Valley. Highway is lower level with limited access control, some at-grade junctions or roundabouts, and generally with 2 lanes in each separated direction. These are generally untolled and funded by the federal government, hence the first one is called Federal Highway linking Klang and Kuala Lumpur. The trunk roads linking major cities and towns in the country are called federal trunk roads, and are generally 2 lanes single carriageway roads, in places with a third climbing lane for slow lorries.

South Africa

Colloquially, the terms "freeway," "highway," and "motorway" are used synonymously. There are very few references to the term "expressway" in South Africa. A freeway, highway or motorway refers to a divided dual carriageway with limited access/egress, with at least two lanes in either direction. A central island, usually either with drainage, foliage or high-impact barriers, provides a visible separation between carriageways in opposite directions. As with the UK and Australia, South Africans drive on the left-hand side of the road and all steering wheels are on the right-hand side of vehicles. Freeways are designated with one of three labels: N (in reference to national roads), R (short for "route," in reference to provincial roads), and M (in reference to metropolitan roads). This has more to do with the location of a road and its function than anything else. In addition, "N" roads usually run the length of the country over long distances, "R" roads usually inter-connect cities and towns within a province, and "M" roads carry heavy traffic in metropolitan areas. Route markings also determine who paid for the road: "N" was paid for by national government, "R" by provincial government and "M" by local government. In recent years, some "R" roads have been re-designated as "N" roads, so that control and funding comes from the South African National Roads Agency.

Switzerland

The term Autobahn is used for normal expressways where there is a central physical structure separating two different directional carriageways. This is often translated into English as motorway. In express routes where there is no central physical structure separating two different directional carriageways, but crossings are still motorway-like otherwise, and traffic lights are not present, the road is instead called an Autostrasse, translated into English as a motorroad. Autostrassen often have a lower speed limit than Autobahnen. See also: Lists of Autobahns

Great Britain and Ireland

In Great Britain and Ireland, unless a route is classified as a motorway, the term used may be main road, trunk road, 'N' road/'R' road (In Ireland), 'A' road/'B' road (In The UK), or, where appropriate, dual carriageway. In the law of England and Wales the term highway covers everything from a footpath (for foot passage only), to a bridleway (for foot, bicycle and equestrian use), to a byway open for all traffic (for all the aforementioned users, plus any motorised user), to unclassified county roads, classified roads, trunk roads, motorways and special roads. In British law, there is no definition of "road", and generally the most common usage refers to: bridleway
- "Carriageway",
- "Footpath",
- "Bridleway" or
- "Byway" In England and Wales the public are said to have a "right of way" over a Highway. This means that, subject to statutory restrictions, the route must be kept clear to allow travel by anyone who wishes to it. At common law, it is forbidden to obstruct a highway or interfere with passage. However, many statutory provisions provide powers to do so (for instance to carry out road works). Rights of way exist both over roads maintained at the public expense (the majority of roads) and over some roads on private property. In this case, the owner must allow passage over the highway. A right of way may be created by custom (i.e. the road has been used for a long period of time) or under the relevant positions of the Highways Act 1980. A right of way may by only be extinguished or diverted by or under an Act of Parliament. For instance, under the Channel Tunnel Rail Link Act 1996 authority is given for the builder of the rail link to stop up certain highways mentioned in Schedule 3 of the act. The contrast to a Highway is a private road over which no right of way exists. Travel on a private road is subject to the consent of the owner of the land.

United States

In the U.S., the terms expressway and freeway are legally defined by federal regulation and under the laws of most U.S. states according to civil engineering usage. However, the distinction between these two terms is not universal, and in several states which built freeways very early on (including Connecticut, Illinois, New Jersey, New York, and Pennsylvania), the terms expressway and freeway have the same meaning. In those states, expressway, the older usage, is often preferred. In New Jersey and Pennsylvania, newer roads are often officially styled freeways, where older roads retain the title "expressway". In New England and New York, the term freeway is rarely if ever used; highway is the generic term for high-speed limited-access roads, though Expressway and Freeway are both used as part of the proper name of some roads. In the rest of the country, freeway is the usual term; however, the distinction between freeways and highways is not always as clear or well-understood as it is in California, which has many of both kinds of highway. In California, freeways are divided, grade-separated, controlled-access highways where private driveways, pedestrians, and bicyclists are forbidden, where speed limits range from 55 to 70 miles per hour, and are usually elevated within major cities. Highways are divided, but may have at-grade or grade-separated intersections as demand requires, private driveways are minimized (but not completely forbidden), bicyclists and pedestrians are sometimes allowed, and the speed limits range from 45 to 55 miles per hour. Within a major city a highway can have commercial buildings along it. All interstate highway routes in California are freeways, most important intracity state routes are freeways, and most important intercity state routes are highways (with sections being upgraded to freeways as necessary). In the U.S., particularly in statutes, the term highway technically has the broader meaning than that given at the beginning of this article (encompassing all state government-maintained roads or canals for cross-city or inter-city traffic), but in colloquial usage is often used to refer only the subset of that category that includes roads less important than a freeway. That subset generally includes roads with 2, 4, or 6 lanes, with or without a center divider, that have at-grade intersections and driveways connecting to adjacent properties. However, even then, such highways are usually built to higher standards (wider lanes and more durable pavement) than the connecting arterial routes, streets, alleys, and driveways. The highest continuous road in the United States is the Trail Ridge Road that runs through the Rocky Mountain National Park in Colorado. The term highway is also often used in colloquial speech where the correct term would be "State Route," or "U.S. Route." For example, California residents frequently refer to Highway 101 rather than U.S. 101.

Further information

For information on the history and local styles of highways around the world refer to
- Auto-Estrada (Portugal)
- Autopista (Spain)
- Autoroute (France)
- Autoroute (Quebec)
- Autobahn (Germany)
- Autostrada (Italy)
- Highways (India)
- Expressway (Mainland China)
- Expressway (Lebuhraya) (Malaysia)
- Freeway, Expressway, and Parkway (United States)
- Freeway (Canada)
- Motorway (United Kingdom)
- Motorway (Ireland)
- National Trunk Highway System (Mainland China)
- Rodovia (Brazil)

External link

- [http://dictionary.law.com/default2.asp?typed=highway&type=1&submit1.x=63&submit1.y=16&submit1=Look+up Legal definition in the U.S.]
- [http://www.us-highways.com/ U.S. Highways: From US 1 to (US 830)]
- [http://www.milebymile.com/ Mile By Mile U.S. Highway Travel Information Guides]
- [http://www.elbruz.org/eroads/AGR_2.htm Full list of Euroroutes with distances] Category:Road infrastructure Category:Road transport ja:高速道路 ms:Lebuhraya

Vehicle

:This article is about the means of transport. For the political meaning, see electoral vehicle. For the economical meaning, see economic vehicle Vehicles are non-living means of transportation. They are most often man-made (e.g. cars, motorcycles, trains, ships, and aircraft), although some other means of transportation which are not made by man can also be called vehicles; examples include icebergs and floating tree trunks. Vehicles may be propelled by animals, e.g. a chariot or an ox-cart. However, animals on their own, though used as a means of transportation, are not called vehicles. This includes humans carrying another human, for example a child or a disabled person. Most land vehicles have wheels. Please see the wheel article for examples of vehicles with and without wheels. Movement without the help of a vehicle or an animal is called locomotion. The word vehicle itself comes from the Latin vehiculum. AVL stands for Automatic Vehicle Location.

Types of vehicles

- Aircraft
- Cars
- Auto rickshaws
- Boats
- Buses
- Coaches
- Motorcycles
- Trains
- Ships
- Vans
- Bicycles
- More...

External Links

- [http://www.epa.gov/greenvehicles/ Green Vehicle Guide]
- [http://www.nhtsa.dot.gov/cars Vehicle Information] Category:Transportation simple:Vehicle

Stop sign

A stop sign is a traffic sign, usually erected at road junctions, that instructs drivers to make a brief and temporary, but complete, stop upon reaching it, and then to proceed only if the way ahead is clear. Stop signs are not generally required at every intersection, but they are often used to control conflicting traffic movements at dangerous intersections which are not busy enough to justify the installation of either traffic lights or, especially in Europe, a roundabout. In the United States and Canada they are commonly used in residential areas, and near places where children play, as a general traffic calming measure. In these countries it is not uncommon for stop signs to be erected on all three or four intersecting roads. The intentional removal of stop signs from their posted locations is a crime in most U.S. states. Fatal accidents caused by someone removing a stop sign on purpose could also result in manslaughter charges against the offender. The purposeful removal of stop signs began in the 1980s as a college prank and, today, one may find illegally obtained stop signs hanging in the occasional college dorm rooms. Anyone who wishes to legitimately obtain a stop sign for home display can purchase one new from a traffic supply house for about US$75. US$ The following remarks concerning the right-of-way rules at intersections with multiple stop signs apply to the United States and Canada:
- Generally, the driver who stops first continues first.
- If two drivers stop simultaneously at stop signs at a single intersection, the rule is that the car that comes to a complete stop first has the right of way. Common sense applies.
- Stop signs may be augmented with additional information such as a plate bearing the legend "4-way stop". This is important, because a driver accustomed to negotiating four-way stops may falsely believe when encountering a two-way stop that cross traffic is required to stop. Since the first car to stop has the right of way at a four-way stop, this driver may believe that it is safe to turn in front of the oncoming traffic. Therefore, if there is only a plain stop sign, the assumption has to be that cross traffic will not stop. "4-way stop" plates are provided on the fail-safe principle that if they are missing (through disrepair, vandalism, etc.) the "more dangerous" message is given. Stop signs, usually based on the American design, are found all over the world, although in Europe they tend to be used far more sparingly than in North America, generally being restricted (on the principle that "familiarity breeds contempt") to situations where coming to a dead stop is absolutely essential because of poor visibility at the intersection concerned. In all countries, the driver must actually stop even if no vehicles or pedestrians are visible. However, some drivers practice the illegal manoeuvre known as a rolling or "California" stop: slowing down significantly but not stopping completely at the sign. Yield signs ("Give way" signs in the UK, Australia, and New Zealand), on the other hand, require the driver only to slow and prepare to stop, but do not require an actual stop if the way ahead is clear.

History

New Zealand Stop signs originated in Detroit, Michigan in 1915. The first had black letters on a white background and were somewhat smaller than the modern one. As they became more widespread, a committee supported by the American Association of State Highway and Transportation Officials (AASHO) met in 1922 to standardize them, and it selected the octagonal shape that has been used in the U.S. ever since. The unique eight-sided shape of the sign allows drivers facing the back of the sign to identify that oncoming drivers have a stop sign and prevent confusion with other traffic signs. In 1924, the sign changed to black on yellow, the predominant color until 1954. Another competing group, the NCSHS, simultaneously advocated an even smaller, red-on-yellow stop sign. All of these signs were typically mounted only two or three feet above the ground. These two organizations conflicted but eventually combined into the Joint Committee on Uniform Traffic Control Devices, which in 1935 published the famous Manual on Uniform Traffic Control Devices for Streets and Highways (MUTCD) detailing the stop sign's appearance. The MUTCD stop sign was altered eight times between 1935 and 1971, mostly dealing with its reflectorization and its mounting height; the most drastic change came in 1954, when the sign gained its white-on-red color. Red is also the color for stop on traffic signals, unifying red as stop signal for drivers worldwide. The mounting height reached its current level of 2.1 m (7 ft) in 1971. Although already widespread, use of the MUTCD stop sign passed into law in the United States in 1966. They were later adopted by the European Union as part of their effort to standardize road travel across member countries.

Different (Non-English) variants

Although English-speaking and European Union countries use the original word "STOP" on stop signs, most countries, and sometimes even smaller political districts, prefer to use a roughly equivalent word in their primary language instead; its appearance is otherwise the same of white text on a red octagon. The few known exceptions include Israel (which uses a solid white hand on a red octagon) and Japan (which uses the local word for Stop in white type on an inverted solid red triangle). Although the word used isn't universally standardized, some commonly seen examples are: European Union

External links

- [http://signalfan.freeservers.com/road%20signs/stopsign.htm History of the Stop Sign in America]
- [http://www.geog.okstate.edu/users/lightfoot/stop/page/main.htm Stop Signs from Around the World]
- [http://www.mycrazyhobby.com/stop/ A Collection of Stop and Yield Signs] Category:Traffic signs

Global city

] ] ] ] :For a city spanning an entire planet, see Ecumenopolis A global city (also known as a world city or world-class city) is a city that has a direct and tangible effect on global affairs through socioeconomic, cultural, and/or political means. In recent years, the term has become increasingly familiar, because of the rise of globalization (i.e., global finance, communications, and travel). The term "global city", as opposed to megacity, was first coined by Saskia Sassen in a seminal 1991 work. __TOC__ Though defining a global city must be partially subjective, these cities are generally seen as meeting most of the following criteria:
- International, first-name familiarity (one would say "Tokyo", not "Tokyo, Japan").
- Active influence and participation in international events and world affairs (for example, New York City is home to the United Nations headquarters, Brussels is home to the EU Parliament and NATO headquarters, Frankfurt is headquarters to the European Central Bank).
- A fairly large population (the center of a metropolitan area with a population of at least one million, typically several million). A good example would be Houston.
- A major international airport (for example, London Heathrow Airport) that serves as an established hub for several international airlines.
- An advanced transportation system that includes several freeways and/or a large mass transit network offering multiple modes of transportation (subway, light rail, regional rail, ferry, or bus). Toronto is an example.
- In the West, several international cultures and communities (such as a Chinatown, a Little Italy, or other immigrant communities). In other parts of the world, such as Asia, cities which attract large foreign businesses, for example Shanghai and Hong Kong.
- International financial institutions, law firms, corporate headquarters (especially conglomerates), and stock exchanges that have influence over the world economy.
- Advanced communications infrastructure that modern trans-national corporations rely on, such as fiberoptics, Wi-Fi networks, cellular phone services, and other high-speed lines of communications.
- World-renowned cultural institutions, such as museums and universities.
- A lively cultural scene, including film festivals, premieres, a thriving music or theatre scene; an Orchestra, an opera company, art galleries, and street performers. Several powerful and influential media outlets with an international reach are based in world cities, such as the BBC, The New York Times, Le Monde, The Chicago Tribune, and The Times. In the Western World, London, New York, Paris, and Tokyo have been traditionally considered the "big four" world cities – not incidentally, they also serve as symbols of global capitalism. However, many people have a personal list, and any two lists are likely to differ based on cultural background, values, and experience. In certain developed countries, especially the United States, the rise of suburbia and the ongoing migration of manufacturing jobs to developing countries has led to significant urban decay. Therefore, to boost urban regeneration, tourism, and revenue, the goal of building a "world-class" city has recently become an obsession with the governments of some mid-size cities and their constituents. The phenomenon of world-city building, albeit with slightly more success, has also been observed in Sydney, Buenos Aires, Frankfurt, and Toronto: each of these cities has emerged as large and influential. Toronto] Toronto] Toronto] Toronto] Toronto] Toronto]

GaWC Inventory of World Cities

An influential attempt to define and categorise world cities, was made by the Globalization and World Cities Study Group & Network (GaWC), based primarily at Loughborough University in England. The roster was outlined in the GaWC Research Bulletin 5 [http://www.lboro.ac.uk/gawc/rb/rb5.html] and ranked cities based on their provision of "advanced producer services" such as accountancy, advertising, finance and law. The Inventory identifies three levels of world cities and several sub-ranks. Note that this roster is weighted toward financial criteria and generally denotes cities in which there are offices of certain multinational companies providing financial and consulting services rather than other cultural, political and economic centres. Alpha World Cities
- 12 points: London, New York City, Paris, Tokyo
- 10 points: Chicago, Frankfurt, Hong Kong, Los Angeles, Milan, Singapore Beta World Cities
- 9 points: San Francisco, Sydney, Toronto, Zürich
- 8 points: Brussels, Madrid, Mexico City, São Paulo
- 7 points: Moscow, Seoul Gamma World Cities
- 6 points: Amsterdam, Boston, Caracas, Dallas, Düsseldorf, Geneva, Houston, Jakarta, Johannesburg, Melbourne, Osaka, Prague, Santiago, Taipei, Washington, DC
- 5 points: Bangkok, Beijing, Montréal, Rome, Stockholm, Warsaw
- 4 points: Atlanta, Barcelona, Berlin, Buenos Aires, Budapest, Copenhagen, Hamburg, Istanbul, Kuala Lumpur, Manila, Miami, Minneapolis, Munich, Shanghai Evidence of World City Formation
- 3 points: Athens, Auckland, Dublin, Helsinki, Luxembourg, Lyon, Mumbai, New Delhi, Philadelphia, Rio de Janeiro, Tel Aviv, Vienna
- 2 points: Abu Dhabi, Almaty, Birmingham (UK), Bogotá, Bratislava, Brisbane, Bucharest, Cairo, Cleveland, Cologne, Detroit, Dubai, Ho Chi Minh City, Kiev, Lima, Lisbon, Manchester, Montevideo, Oslo, Riyadh, Rotterdam, Seattle, Stuttgart, The Hague, Vancouver
- 1 point: Adelaide, Antwerp, Arhus, Baltimore, Bangalore, Bologna, Brasília, Calgary, Cape Town, Colombo, Columbus, Dresden, Edinburgh, Genoa, Glasgow, Gothenburg, Guangzhou, Hanoi, Kansas City, Leeds, Lille, Marseille, Richmond, St. Petersburg, Tashkent, Tehran, Tijuana, Turin, Utrecht, Wellington There is a schematic map of the GaWC cities at their website, [http://www.lboro.ac.uk/gawc/citymap.html].

Other global cities

The GaWC list is based on specific criteria and, thus, may not include other cities of global significance or elsewhere on the spectrum. For example, cities with the following:

- large populations, proper and agglomerated
- diverse [http://hdr.undp.org/reports/global/2004/pdf/hdr04_chapter_5.pdf demographic constituencies (p. 99)]
- based on [http://pdf.wri.org/wr98_ud.pdf various indicators]:
- [http://www.un.org/Pubs/CyberSchoolBus/special/habitat/profiles/ population, habitat (selected profiles)], [http://www.wbcsd.org/DocRoot/uu8taBpoTDXkvBiJHuaU/english_full_report.pdf mobility], and [http://www.un.org/esa/population/publications/wup2003/WUP2003Report.pdf urbanisation]
- significant financial capacity/output:
- [http://pdf.wri.org/wr98_ud2.pdf city/regional] GDP [http://www.unhabitat.org/programmes/guo/documents/1998.zip (data sets in ZIP)]
- stock market [http://www.bloomberg.com/markets/stocks/wei.html indices]/market capitalisation
- headquarters for multinational corporations
- [http://www.lboro.ac.uk/gawc/rb/rb179.html financial service provision]; e.g., banks, accountancy
- employment
- based on [http://www.mercerhr.com/pressrelease/details.jhtml?idContent=1173105 quality of life] or [http://www.unchs.org/Istanbul+5/116.pdf city development]
- based on [http://www.mercerhr.com/pressrelease/details.jhtml/dynamic/idContent/1142150 costs of living]
- based on personal wealth; e.g., [http://www.forbes.com/2005/03/09/bill05land.html number of billionaires]
- significant transport infrastructure:
- airports with significant passenger traffic ([http://www.lboro.ac.uk/gawc/rb/rb157.html analysis]) or cargo movements
- extensive and [http://people.hofstra.edu/geotrans/eng/ch6en/conc6en/largestpublictransit.html popular] mass transit systems
- [http://www.publicpurpose.com/ut-crintl.pdf prominent rail usage]
- [http://www.publicpurpose.com/hwy-intltr.htm road vehicle usage]
- [http://www.geohive.com/charts/seaport.php major seaports]

- significant technological capabilities/infrastructure:
- [http://homepages.ipact.nl/~egram/skylines.html prominent skylines/skyscrapers]
- significant institutions:
- educational institutions; e.g., [http://www.thes.co.uk/downloads/rankings/world-rankings-16pages.pdf universities (registration required)], [http://www.lboro.ac.uk/gawc/rb/rb161.html international student attendance]
- research facilities
- health facilities; e.g, hospitals, medical laboratories
- sites of pilgrimage for world religions
- hosting headquarters for international organizations
- cities containing UNESCO [http://whc.unesco.org/en/list/ sites of historical and cultural significance]
- high endowments of cultural facilities:
- notable museums and galleries
- notable opera
- notable orchestras
- notable film centres and film festivals
- notable theatre centres
- sites of major international sports events; e.g., Olympic Games sites [http://www.lboro.ac.uk/gawc/rb/rb154.html (Olympic/tourism analysis)]
- tourism throughput:
- visitors
- economy
- events

Table of the cities of the world

for selected criteria

Place	Population of city [http://www.mongabay.com/igapo/cities.htm]	Population of metropolitan area [http://www.mongabay.com/igapo/cities.htm]	Percentage foreign born [http://news.bbc.co.uk/2/hi/americas/3898795.stm]	Cost of living [http://www.mercerhr.com/summary.jhtml;jsessionid=F4S4OVM1LKMMSCTGOUGCHPQKMZ0QYI2C?idContent=1142150]	Metro system by passenger rides	Largest airports [http://www.airports.org/cda/aci/display/main/aci_content.jsp?zn=aci&cp=1-5-54_9_2__]	Number of skyscrapers [http://www.emporis.com/en/bu/sk/st/ma/ci/]	Number of billionaires [http://www.ifsl.org.uk/uploads/PB_Private_Wealth_2004.pdf]
1	Shanghai	Tokyo	Miami	Tokyo	Moscow	Atlanta	Hong Kong	London
2	Bombay	New York City	Toronto	Osaka	Tokyo	Chicago	New York City	New York City
3	Karachi	Mexico City	Los Angeles	London	Seoul	London	Singapore	Moscow
4	Buenos Aires	Mumbai	Vancouver	Moscow	Mexico City	Tokyo	São Paulo	Geneva
5	New Dehli	São Paulo	New York City	Seoul	New York City	Los Angeles	Seoul	Los Angeles
6	Manila	Los Angeles	Singapore	Geneva	Paris	Dallas	Tokyo	Hong Kong
7	Moscow	Shanghai	Sydney	Zürich	Osaka	Paris	Istanbul	San Francisco
8	Seoul	Lagos	Abidjan	Copenhagen	London	Frankfurt	Rio de Janeiro	Paris
9	São Paulo	Calcutta	London	Hong Kong	Hong Kong	Amsterdam	Toronto	Tokyo
10	Istanbul	Buenos Aires	Paris	Oslo	St. Petersburg	Denver	Buenos Aires

External Links

- "'U.S. Cities in the 'World City Network'" by Peter J. Taylor and Robert E. Lang of the Brookings Institution
- [http://www.brookings.edu/metro/pubs/20050222_worldcities.htm Key Findings]
- [http://www.brookings.edu/dybdocroot/metro/pubs/20050222_worldcities.pdf Full Report] in PDF Format
- [http://science.uniserve.edu.au/school/curric/geography/urban.html Repository of Links Relating to Urban Places]
- [http://hsc.csu.edu.au/geography/urban/cities/worldcities/World_Cities.html World Cities] article by Jennifer Curtis of Charles Sturt University
- [http://www.irows.ucr.edu/conferences/globgis/papers/Smith.htm The World-System’s City System: A Research Agenda] by Jeffrey Kentor and Michael Timberlake of the University of Utah and David Smith of University of California, Irvine
- [http://www.unchs.org/Istanbul+5/statereport.htm The State of the World's Cities, 2001], UN Human Settlements Programme Category:Cities Category:Metropolitan areas

Jersey barrier

A Jersey barrier or Jersey wall was originally developed to divide multiple lanes on a highway by the state of New Jersey in the United States. A Jersey barrier stands 3–5 feet tall and is made of poured concrete. Their widespread use on the highway has led to many other uses as a general barrier. They are also known as K-rails (especially in Western states or when used temporarily during roadway construction) or traffic dividers. concrete The design of the Jersey barrier was specifically intended to minimize damage and reduce the likelihood of a car crossing into oncoming lanes in the event of a collision. For the more common shallow-angle hits, the Jersey barrier is intended to minimize sheet metal damage by allowing the vehicle tires to ride up on the lower sloped face. For higher impact angles, the Jersey barrier is actually a multistage barrier. The front bumper impacts the upper sloped face and slides upwards. This interaction initiates lifting of the vehicle. If the bumper is relatively weak, the front end starts to crush before any uplift occurs. Then, as the vehicle becomes more nearly parallel with the barrier, the wheel contacts the lower sloped face. Most of the additional lift of the vehicle is caused by the lower sloped face compressing the front suspension. However, wheel side-scrubbing forces provide some additional lift, particularly if the barrier face is rough. Therefore, exposed aggregate a