US 131, M-6 and 68th Street in Wyoming, Michigan shows many of the features of controlled access highways - opposing traffic on separate carriageways, no at-grade intersections and no direct access to properties.

A controlled-access highway is a highway designed exclusively for high-speed vehicular traffic, with all traffic flow and ingress/egress regulated. They are known by various terms worldwide, including Autobahn, autopista, autoroute, autostrada, snelweg, freeway, motorway, and sometimes less precise terms such as highway, expressway, parkway, or turnpike.

A controlled-access highway provides an unhindered flow of traffic, with no traffic signals, intersections or property access. They are free of any at-grade crossings with other roads, railways, or pedestrian paths, which are instead carried by overpasses and underpasses across the highway. Entrance and exit to the highway are provided at interchanges by slip roads (ramps), which allow for speed changes between the highway and arterial thoroughfares and collector roads. On the highway, opposing directions of travel are physically separated by a central reservation (median), such as a strip of grass or boulders, or by a traffic barrier.

Controlled-access highways, as they exist today, evolved during the first half of the twentieth century. The Long Island Motor Parkway, opened in 1908 as a private venture, was the world's first limited-access roadway. Germany began to build its famous Reichsautobahn controlled-access highway network (then referred to as a Dual Highway) following the First World War. It rapidly assembled a nationwide system of such roads in anticipation of their use in World War II. Italy followed shortly thereafter, opening its first Autostrada in 1925. The first North American freeways (known as parkways) opened in the New York City area in the 1920s. Britain, heavily influenced by the railway,^{[citation needed]} did not build its first motorway until the mid-1950s.

Most technologically advanced nations feature an extensive network of freeways or motorways. Many have a national-level system of route numbering. The highway has brought with it the ability to access almost any part of the world with comfort and speed, improved fuel efficiency, and improved economic and cultural access among communities.

Definition[link]

There is no formal definition of the English-language words "motorway", "freeway" and "expressway" or of the equivalent foreign-language words autoroute, autobahn autostrade that are accepted world-wide - in most cases these words are defined by local statute or design standards. Descriptions that are widely used include:

History[link]

Historical map of the original A8-A9 motorway, Italy. The first motorway ever built in the world, 21 September 1924.

Controlled-access highways, as they exist today, evolved during the first half of the twentieth century. The Long Island Motor Parkway, opened in 1908 as a private venture, was the world's first limited-access roadway. It included many modern features, including banked turns, guard rails and reinforced concrete tarmac.^[2] Modern controlled-access highways originated in the early 1920s in response to the rapidly increasing use of the automobile, the demand for faster movement between cities and as a consequence of improvements in paving processes, techniques and materials. These original high-speed roads were referred to as "dual highways" and, while divided, bore little resemblance to the highways of today. The first dual highway in the world opened in 1924 between Milan and Varese and now forms parts of the A8 and A9 motorways. This highway, while divided, featured only one lane in each direction and no interchanges. Shortly thereafter, in 1924, the Bronx River Parkway was opened to traffic. The Bronx River Parkway was the first road in North America to utilize a median strip to separate the opposing lanes, to be constructed through a park and where intersecting streets crossed over bridges.^[3][4] Construction of the Bonn-Cologne autobahn began in 1929 and was opened in 1932 by the mayor of Cologne.^[5]

Design[link]

Highway 401, an 18 through lane, quad roadway highway in southern Ontario, an extreme example of multilane collector-express freeway design. Seen here is the highway passing through Toronto.

Freeways, by definition, have no at-grade intersections with other roads, railroads or multi-use trails. Movable bridges, such as the Interstate Bridge on Interstate 5 between Oregon and Washington, do require drivers to stop for ship traffic.

The crossing of freeways by other routes is typically achieved with grade separation either in the form of underpasses or overpasses. In addition to sidewalks (footpaths) attached to roads that cross a freeway, specialized pedestrian footbridges or tunnels may also be provided. These structures enable pedestrians and cyclists to cross the freeway at that point without a detour to the nearest road crossing.

Access to freeways is typically provided only at grade-separated interchanges, though lower-standard right-in/right-out access can be used for direct connections to side roads. In many cases, sophisticated interchanges allow for smooth, uninterrupted transitions between intersecting freeways and busy arterial roads. However, sometimes it is necessary to exit onto a surface road to transfer from one freeway to another. One example in the United States (notorious for the resulting congestion) is the connection from Interstate 70 to the Pennsylvania Turnpike (Interstate 70 and Interstate 76) through the town of Breezewood, Pennsylvania.^[6]

Speed limits are generally higher on freeways and are occasionally nonexistent (as on much of Germany's Autobahn network). Because higher speeds reduce decision time, freeways are usually equipped with a larger number of guide signs than other roads, and the signs themselves are physically larger. Guide signs are often mounted on overpasses or overhead gantries so that drivers can see where each lane goes. Exit numbers are commonly derived from the exit's distance in miles or kilometers from the start of the freeway. In some areas, there are public rest areas or service areas on freeways, as well as emergency phones on the shoulder at regular intervals.

In the United States, mileposts start at the southern or westernmost point on the freeway (either its terminus or the state line). California, Ohio, and Nevada use milepost systems in which the markers indicate mileage through the state's individual counties. However, in Nevada and Ohio, and freeways that pass through Kern County, California, also use the standard milepost system concurrently with their respective postmile systems.

Cross sections[link]

Two-lane freeways, often undivided, are sometimes built when traffic volumes are low or right-of-way is limited; they may be designed for easy conversion to one side of a four-lane freeway. Otherwise, freeways typically have at least two lanes in each direction; some busy ones can have as many as 16 or more lanes^[7] in total.

In San Diego, California, Interstate 5 has a similar system of express and local lanes for a maximum width of 21 lanes on a two-mile segment between Interstate 805 and California State Route 56. In Mississauga, Ontario, Highway 401 uses collector-express lanes for a total of 18 lanes through its intersection with 403/410 and 427.

Diagram showing lanes and road layout (Irish road markings)

These wide freeways may use separate collector and express lanes to separate through traffic from local traffic, or special high-occupancy vehicle lanes, either as a special restriction on the innermost lane or a separate roadway, to encourage carpooling. These HOV lanes, or roadways open to all traffic, can be reversible lanes, providing more capacity in the direction of heavy traffic, and reversing direction before traffic switches. Sometimes a collector/distributor road, a shorter version of a local lane, shifts weaving between closely spaced interchanges to a separate roadway or altogether eliminates it.

In some parts of the world, notably parts of the U.S., frontage roads form an integral part of the freeway system. These parallel surface roads provide a transition between high-speed "through" traffic and local traffic. Frequent slip-ramps provide access between the freeway and the frontage road, which in turn provides direct access to local roads and businesses.^[8]

French A10 near Orléans showing hard shoulder and emergency telephone. The broken demarcation line for the hard shoulder is specific to France

Except on some two-lane freeways (and very rarely on wider freeways), a median separates the opposite directions of traffic. This strip may be as simple as a grassy area, or may include a crash barrier such as a "Jersey barrier" or an "Ontario Tall Wall" to prevent head-on collisions.^[9] On some freeways, the two carriageways are built on different alignments; this may be done to make use of available corridors in a mountainous area or to provide narrower corridors through dense urban areas.^{[citation needed]}

Some roads in Ohio that conform to freeway criteria use at-grade intersections in lieu of over/under-passes, with occasional interchanges to avoid signalized traffic interruption (i.e., traffic lights are omitted). Examples include US 23 between OH-15's eastern terminus and Delaware, Ohio, along with Highway 15 between its eastern terminus and I-75, US-30, OH-29/US-33, and US-35 in western and central Ohio. These highways are fundamentally expressways, but expressways tend to have lower design speeds, and signalized at-grade intersections.

Control of access[link]

Control of access is a legal status which prohibits the types of vehicles which use a highway and the points at which they can access it.

Freeways are usually limited to motor vehicles of a minimum power or weight; signs may prohibit bicyclists, pedestrians and equestrians and impose a minimum speed. It is possible for non-motorized traffic to use facilities within the same right-of-way, such as sidewalks constructed along freeway-standard bridges and multi-use paths next to freeways such as the Suncoast Trail along the Suncoast Parkway in Florida.

In some US jurisdictions, especially where freeways replace existing roads, non-motorized access on freeways is permitted. Different states of the United States have different laws. Cycling on freeways in Arizona may be prohibited only where there is an alternative route judged equal or better for cycling.^[10] Wyoming, the least populated state, allows cycling on all freeways. Oregon allows bicycles except on specific urban freeways in Portland and Medford.^[11]

In countries such as the United Kingdom and Germany, the difference between a normal road and a freeway-class road (motorway/autobahn) is the restriction of low-speed traffic. Many roads are built to freeway standards but are not legally a freeway-class road for this reason. Indeed, some freeway-class roads are downgraded for short stretches where no alternative exists, to allow low-speed traffic; examples in the UK include the Dartford Crossing (the furthest downstream public crossing of the Thames), and the former Cumberland Gap, as well as sections of the A1 not yet designated A1(M), various lengths of the A5, and the entirety of other important and near-motorway-standard links such as the A14, A34, A38, A42, A50, A55... long stretches of which carry 70 mph (110 km/h) speed limits. The reasons for such designation vary – physical lack of space (A55), restricted budget (e.g. A42 – a full-standard motorway would have been more expensive than an A-road; a motorway with additional service roads further still), to permit local access in remote areas or because of legislative or political wrangling (easier to have A-road construction or upgrade authorised and accepted than a more emotionally charged "motorway scheme", and does not require issuing of Special Road orders). Continental European non-motorway dual carriageways can have limits as high as 110–120 kilometres per hour (68–75 mph). U.S. Route 23 in Ohio has a speed limit as high as 65 mph (105 km/h) but isn't legally a freeway-class road since it has no disclaimers saying that low-speed vehicles are prohibited; it also has at-grade intersections like expressway-class roadways.

Research shows 85 percent of motor vehicle-bicycle crashes follow turning or crossing at intersections.^[12] Freeway travel eliminates almost all those conflicts save at entrance and exit ramps – which, at least on those freeways where cycling has not been banned, have sufficient room and sight for cyclists and motorists. An analysis of crashes in Arizona showed no safety problems with cycling on freeways. Fewer than one motor vehicle-bicycle crash a year was recorded on nearly 2000 shoulder-miles open to cyclists in Arizona.^[13]

Construction techniques[link]

The most frequent way freeways are laid out is usually by building them from the ground up after things such as forestry or buildings are cleared away. Sometimes they deplete farmland, but other methods have been developed for economic, social, and even environmental reasons.

Full freeways are sometimes made by converting at-grade expressways or by replacing at-grade intersections with overpasses; however, any at-grade intersection that ends a freeway remains.^{[citation needed]} Often, when there is a two-lane undivided freeway or expressway, it is converted by constructing a twin corridor on the side by leaving a median between the two travel directions. The opposing side for the old two-way corridor becomes a passing lane.

Other techniques involve building a new carriageway on the side of a divided highway that has a lot of private access on one side and sometimes has long driveways on the other side since an easement for widening comes into place, especially in rural areas.

When a "third" carriageway is added, sometimes it can shift a directional carriageway by 50–200 feet (15–61 m) (or maybe more depending on land availability) as a way to retain private access on one side that favors over the other. Other methods involve constructing a service drive that shortens the long driveways (typically by less than 100 metres (330 ft)).

Environmental effects[link]

Traffic congestion, such as this on Interstate 75 in Atlanta, is tied to photochemical smog.

Controlled-access highways have been constructed both between urban centres and within them, leading to the sprawling suburban development found near most modern cities. They ideally serve to reduce travel times and accident rates, though the higher speeds have increased the severity and death rates of the collisions that do occur.

Highways have been heavily criticized by environmentalists, urbanists, and preservationists for the noise,^[14] pollution, and economic shifts they bring.^[15] Additionally, they have been criticized by the driving public for the inefficiency with which they handle peak hour traffic.^[16][17][18]

Often, rural highways open up vast areas to economic development and municipal services, generally raising property values. In contrast to this, above-grade highways in urban areas are often a source of lowered property values, contributing to urban decay. Even with overpasses and underpasses, neighbourhoods are divided — especially impoverished ones where residents are less likely to own a car, or to have the political and economic influence to resist construction efforts.^[19] Beginning in the early 1970s, the U.S. Congress identified freeways and other urban highways as responsible for most of the noise exposure of the U.S. population.^[20] Subsequently, computer models were developed to analyze freeway noise and aid in their design to help minimize noise exposure.^[21]

Some cities have implemented freeway removal policies in which freeways have even been demolished and reclaimed as boulevards or parks, notably in Portland (Harbor Drive), New York City (West Side Highway), Boston (Central Artery), San Francisco (Embarcadero Freeway) and Milwaukee (Park East Freeway).

An alternative to surface or above ground freeway construction has been the construction of underground urban freeways using tunnelling technologies. This has been extremely successful in the Australian cities of Sydney (which has five such freeways) and Melbourne (which has two such freeways). This has had the benefit of removing traffic from surface roads and in the case of Melbourne's Eastlink Motorway, has helped preserve an ecologically sensitive area from destruction.

Highway lighting can have a negative influence on those living close to the freeway. High-mast lighting is an alternative as it concentrates the light on the road, but the tall structures can also have a NIMBY effect.

Other Australian cities face similar problems (lack of available land, cost of home acquisition, aesthetic problems, and community opposition). Brisbane, which also has to contend with physical boundaries (the river) and heavy population increases, has embraced underground tunnel freeways. There are currently three under active development, one of which (the North-South Bypass Tunnel) is currently under construction. All of the planned tunnels include provisions for public transport, whether underground or in reclaimed space on the surface.^[22]

Freeway opponents have found that freeway expansion is often self-defeating: expansion simply generates 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 commute to more remote locations. Over time, the freeway and its environs become congested again as both the average number and distance of trips increases. This idea is known as induced demand.^[23][24]

Urban planning experts such as Drusilla Van Hengel, Joseph DiMento, and Sherry Ryan argue that although properly designed and maintained freeways may be convenient and safe, at least in comparison to uncontrolled roads, they may not expand recreation, employment and education opportunities equally for different ethnic groups, or for people located in certain neighborhoods of a given city.^[25] Still, they may open new markets to some small businesses.^[26]

Construction of urban freeways for the U.S. Interstate Highway System, which began in the late 1950s, led to the demolition of thousands of city blocks, and the dislocation of many more thousands of people. The citizens of many inner city areas responded with the freeway and expressway revolts. Through the study of Washington's response, it can be shown that the most effective changes came not from executive or legislative action, but instead from policy implementation. One of the foremost rationales for the creation of the U.S. Department of Transportation (DOT) was that an agency was needed to mediate between the conflicting interests of interstates and cities. Initially, these policies came as regulation of the state highway departments. Over time, DOT officials re-focused highway building from a national level to the local scale. With this shift of perspective came an encouragement for alternative transportation, and locally based planning agencies.^[27]

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 federally funded 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), the tax revolt movement,^[28] and growing popular support for high-speed mass transit in lieu of new freeways.

Route numbering[link]

Great Britain[link]

In England and Wales, the numbers of major motorways followed a numbering system separate to that of the A-road network, though based on the same principle of zones.^[29] Running clockwise from the M1 the zones were defined for Zones 1 to 4 based on the proposed M2, M3 and M4 motorways. The M5 and M6 numbers were reserved for the other two planned long distance motorways.^[30] The Preston Bypass, the UK's first motorway, should have been numbered A6(M) under the scheme decided upon, but it was decided to keep the number M6 as had already been applied.^[30] Certain portions or bypasses of A-roads may be designated as motorways, the name of these portions being given the suffix "(M)". An example is the A1(M).^[31]

In Scotland, where the Scottish Office (superseded by the Scottish Government in 1999) rather than the Ministry of Transport and Civil Aviation had the decision, there is no zonal pattern, but rather the A-road rule is strictly enforced. It was decided to reserve the numbers 7, 8 and 9 for Scotland.^[32] The M8 follows the route of the A8, and the M85 became part of the M90 when the A90 was re-routed along the path of the A85.^[specify]

Northern Ireland[link]

Signage on the M6 near Kinnegad in Ireland. This is a standard sign in many European countries to indicate the start of motorway regulations. In this case the appropriate motorway number is shown and in accordance with Irish practice a continuous yellow lines indicate a motorway rather than HQDC.

In Northern Ireland a distinct numbering system is used, which is separate from the rest of Ireland and from Britain, though the classification of roads along the lines of A, B, and C is universal throughout the UK and the Isle of Man. According to a written answer to a parliamentary question to the Northern Ireland Minister for Regional Development, there is no known reason as to how Northern Ireland's road numbering system was devised.^[33] However motorways, as in the rest of the UK and Ireland, are numbered M, with the two major motorways coming from Belfast being numbered M1 and M2. The M12 is a short spur of the M1 with the M22 being a short continuation (originally intended to be a spur) of the M2. There are two other motorways, the short M3 and a motorway section of the A8 road, known as the A8(M) (similar to how motorway sections of A-roads in Great Britain are numbered).

Republic of Ireland[link]

In the Republic of Ireland, motorway and national road numbering is quite different to the UK convention. Since the passage of the Roads Act 1993, all motorways are part of, or form, national primary roads. These routes are numbered in series, (usually, radiating anti-clockwise from Dublin, starting with the N1/M1) using numbers from 1 to 33 (and, separately from the series, 50). Motorways use the number of the route of which they form part, with an M prefix rather than N for national road (or in theory, rather than R for regional road).^[34] In most cases, the motorway has been built as a bypass of a road previously forming the national road (e.g. the 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).

Under the previous legislation, the Local Government (Roads and Motorways) Act 1974, motorways theoretically existed independently to national roads, however the short sections of motorway opened during this act, except for the M50, always took their number from the national road that they were bypassing. The older road was not downgraded at this point (indeed, regional roads were not legislated for at this stage). Older signage at certain junctions on the M7 and M11 can be seen reflecting this earlier scheme, where for example N11 and M11 can be seen coexisting.

The M50, an entirely new national road, 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 in 1994 as the N50 route (it had only a short section of non-motorway section form the Junction 11 Tallaght to Junction 12 Firhouse until its extension as the Southern Cross Motorway). The M50's designation was chosen as a recognisable number. As of 2010, the N34 is the next unused national primary road designation. In theory, a motorway in Ireland could form part off ]a regional road.^[34]

Elsewhere[link]

An example of sign on Swiss route 2/EuroRoute 35 near Lugano, Switzerland.

In Hungary, similar to Ireland, motorway numbers can be derived from the original national highway numbers (1–7), with an M prefix attached, e.g. M7 is on the route of the old Highway 7 from Budapest towards Lake Balaton and Croatia. New motorways not following the original Budapest-centered radial highway system get numbers M8, M9, etc., or M0 in the case of the ring road around Budapest.

Also in the Netherlands, motorway numbers can be derived from the original national highway numbers, but with an A (Autosnelweg) prefix attached, like A9 .

In Germany motorways have the prefix A (Autobahn). If the following number is an odd number the motorway generally follows a North-South direction, even-numbered motorways generally follow an East-West direction

In New Zealand, as well as in the Scandinavian countries, in Finland, Brazil and Russia, motorway numbers are also derived from the state highway route that they form a part of, but unlike Hungary and Ireland, they are not distinguished from non motorway sections of the same state highway route. In the cases where a new motorway acts as a bypass of a state highway route, the original state highway is either stripped of that status or renumbered. A low road number means a road suitable for long distance driving. In Switzerland, as of April 2011, there are 1,763.6 kilometres (1,095.9 mi) of a planned 1,893.5 kilometres (1,176.6 mi) of motorway completed. The country is mountainous with a high proportion of tunnels, there are 220 totaling 200 kilometres (120 mi), which is over 12% of the total motorway length.^[35]

In Australia, motorway numbering varies from state to state. Currently most states are adopting numbering systems with the prefix M for motorways.

In Pakistan, motorways are denoted with the prefix M.

Regional variation[link]

While the design characteristics listed above are generally applicable around the globe, every jurisdiction provides its own specifications and design criteria for controlled-access highways.

Australia[link]

Most of Australia's capital cities feature a motorway network within their urban areas. Sydney, Melbourne, Brisbane and Perth each feature freeway and motorway systems, while Canberra, Adelaide, Hobart and the regional centres of Newcastle, Geelong, Gold Coast, and Wollongong feature a selection of limited-access routes. Outside these areas traffic volumes do not generally demand motorway-standard access, although heavily trafficked regional corridors such as Sydney–Newcastle (M1 Sydney–Newcastle Freeway), Brisbane–Gold Coast (M1 Pacific Motorway), Melbourne–Geelong (M1 Princes Freeway) and that form part of major long-distance routes feature high-standard motorway links.

While Sydney and Canberra (NH23 Federal Highway (Australia)) are the only two Australian capitals connected by a continuous dual-highway, upgrades to full dual-highway of the heavy-use Sydney–Melbourne (A31/M31 Hume Highway/Freeway) and Sydney–Brisbane (M1 Pacific Highway) interstate routes, a total length of more than 2,000 km (1,200 mi), are underway. As of mid-2011 the NH23 was not a true controlled-access highway as many country settlements had at-level access to the highway with a large (20 m) central reservation providing a refuge for traffic that had to cross one carriageway to get to the other.^[36]

Unlike many other countries, Australia's motorways are being opened to cyclists. As the respective state governments upgrade their state's motorways bicycle lanes are being added and/or shoulders widened alongside the motorways.

Belgium[link]

Before the 1970s, lorry drivers took long detours just to avoid Belgium. The country was at the time well known for its poor road standards.^{[citation needed]} Since from the early 1970s, Belgium has built a very good motorway system. This concerns through passing motorways to and from the Netherlands, Germany, Luxembourg, France and the UK by ferries. They connect to the main cargo and ferry harbours, city ring roads, local motorways. Belgium today has the longest total motorway length per area unit of any country in the world.^{[citation needed]} Most of the motorway system has at least three lanes in each direction, and all motorways have overhead lighting, even far from towns and cities.

Brazil[link]

The Rodovia dos Imigrantes (SP-160) crossing the Serra do Mar in São Paulo State, Brazil. The original highway was built as a single carriageway in 1986, and a second carriageway was added in 2002. Advanced technology allowed for a more modern design and a dramatic reduction in deforestation during construction. The complex terrain the motorway overcomes turned it into a worldwide reference.

Although some 10,000 kilometres (6,200 mi) of Brazilian highway is built to motorway-standard, there is no distinct designation for controlled-access highways in the Brazilian federal and state highway systems. The term autoestrada (Portuguese for "motorway") is not commonly used in Brazil; the terms estrada ("road") and especially rodovia ("highway") are instead preferred. Nevertheless, the most technically advanced motorways in Brazil are defined Class 0 motorways by the National Department of Transport Infrastructure (DNIT). These motorways are built to safely allow for vehicular speeds of up to 130 km/h (81 mph). In mountainous terrain, the maximum allowable grade is 5% and maximum allowable radius is 665 m (with 12% super-elevation).

São Paulo state, with 4,700 kilometres (2,900 mi) of motorway, has the most in the country. It is also the state with more highways conceded to the private sector, resulting in the highest value of toll fares per kilometer of highway.

Brazil's first motorway, the Rodovia Anhanguera, was completed in 1953 as an upgrade of the earlier single-carriageway highway. That same year, construction of the second carriageway of Rodovia Anchieta began. Motorway construction, most projects in the form of upgrades of older single-carriageway highways, quickened in the following decades. The current Class 0 motorways include: Rodovia dos Bandeirantes, Rodovia dos Imigrantes, Rodovia Castelo Branco, Rodovia Ayrton Senna/Carvalho Pinto, Rodovia Osvaldo Aranha (also known as "Free-way") and São Paulo's Metropolitan Beltway Rodoanel Mario Covas, all modern, post-70's highways meeting modern European standards. Other stretches of highway such as the under-construction south BR-101 and Rodovia Régis Bittencourt are of older design standards.

China[link]

Chinese expressway, complete with signage. Shown here is the G106 (Jingkai Expressway section) in southern Beijing. The Chinese expressway network has increased ten-fold since 1999 and as of 2012 was the second largest in the world. (Summer 2004 image)

The National Trunk Highway System (NTHS) expressway network of the People's Republic of China is the second longest in the world, just 1,000 miles (1,600 km) short of the U.S. interstate system as of 2010.^[37] The total length of China's expressways was 85,000 kilometres (53,000 mi) by the end of 2011,^[38] the world's second longest only after the United States and roughly equal to Canada, Germany, France and Japan combined. In 2009, 4,719 kilometres (2,932 mi) of expressways were added to this network.^[39]

Expressways in China are a fairly recent addition to a complicated network of roads. According to Chinese government sources, China did not have any expressways before 1988.^[40] One of the earliest expressways nationwide was the Jingshi Expressway between Beijing and Shijiazhuang in Hebei province. This expressway now forms part of the Jingzhu Expressway, currently one of the longest expressways nationwide at over 2,000 kilometres (1,200 mi).

Denmark[link]

Denmark has a well covered motorway system today, which due to the county's geography with many islands have been difficult to build. The longest bridges are the Great Belt and the Øresund bridges to Skåne (Scania) in southern Sweden. Both are motorways with dual electrical train tracks added. A motorway bridge across the Fehmarn Belt to Germany is planned. Around Copenhagen, two ring motorways have been built. Even roads with less than 10.000 vehicles per day have been built in the most northern part of Jutland. This was made to assure that all ferry traffic will be directed to the motorway system as soon as possible.^{[citation needed]}

Germany[link]

German Motorway (Reichsautobahn) 1943 - one of the world's earliest motorways.

Germany's autobahn network has a total length of about 12,800 km, or 7,950 miles (in 2010), which ranks as the fifth-longest in the world behind the Interstate Highway System of the United States, the National Trunk Highway System (NTHS) of the People's Republic of China, the expressways of the National Highway System of Canada and the Autopistas of Spain. German autobahns have no general speed limit (though about 47% of the total length is subject to local and/or conditional limits), but the advisory speed limit Richtgeschwindigkeit) is 130 km/h (81 mph).

Great Britain[link]

A map Shewing Future Pattern of Principal National Routes was issued by the Ministry of War Transport in 1946^[41] shortly before the law that allowed roads to be restricted to specified classes of vehicle (the Special Roads Act 1949) was passed.^[42] The first section of motorway, the M6 Preston Bypass, opened in 1958^[43] followed by the first major section of motorway (the M1 between Crick and Berrygrove), which opened in 1959.^[43] From then onwards, motorways opened on a regular basis right into the 1980s;^[44] by 1972 the first 1,000 miles (1,609 km) of motorway had been built.^[45]

Whilst roads outside of urban areas continued to be built throughout the 1970s, opposition to urban routes became more pronounced. Most notably, plans by the Greater London Council for a series of ringways were cancelled following extensive road protests and a rise in costs.^[46] In 1986 the compromised, single-ring, M25 motorway was completed.^[47] In 1996 the total length of motorways reached 2,000 miles (3,219 km).^[48]

India[link]

Expressways in India make up more than 600 km (370 mi) of the Indian National Highway System^[49] on which they are the highest class of road. The National Highways Development Project is underway to add an additional 18,637 km (11,580 mi) of expressways to the network by the year 2022.^[50][51]

Ireland[link]

Northern Ireland[link]

Legal authority existed in the Special Roads Act (Northern Ireland) 1963 similar to that in the 1949 Act.^[52] The first motorway to open was the M1 motorway, though it did so under temporary powers until the Special Roads Act had been passed.^[53] Work on the motorways continued until the 1970s when the oil crisis and The Troubles both intervened causing the abandonment of many schemes.^[54]

Republic of Ireland[link]

In the Republic of Ireland the Local Government (Roads and Motorways) Act 1974 made motorways possible, although the first section, the M7 Naas Bypass, did not open until 1983. The first section of the M50 opened in 1990, a part of which was Ireland's first toll motorway, the West-Link. However it would be the 1990s before substantial sections of motorway were opened in Ireland, with the first completed motorway – the 83 km (52 mi) M1 motorway – being finished in 2005.

Under the Transport 21 infrastructural plan,^[55] motorways or high quality dual carriageways were built between Dublin and the major cities of Cork, Galway, Limerick and Waterford by the end of 2010. Other shorter sections of motorway either have been or will be built on some other main routes. In 2007 legislation (the Roads Bill 2007) was created to allow existing roads be designated motorways by order because previously legislation allowed only for newly built roads to be designated motorways.

As a result, most HQDCs nationwide (other than some sections near Dublin on the N4 and N7, which did not fully meet motorway standards) were reclassified as motorways. The first stage in this process occurred when all the HQDC schemes open or under construction on the N7 and N8, and between Kinnegad and Athlone on the N6 and Kilcullen and south of Carlow on the N9, were reclassified motorway on 24 September 2008. Further sections of dual carriageway were reclassified in 2009.

As of December 2011, the Republic of Ireland has around 1,017 kilometres (632 mi) of motorways.

Italy[link]

The first motorway ever built in the world was the Autostrada dei laghi, inaugurated on 21 September 1924 in Milan. It linked Milan to Varese; it was then extended to Como, near the border with Switzerland, inaugurated on 28 June 1925. Piero Puricelli, the engineer who designed this new type of road, decided to cover the expenses by introducing a toll.^[56][57]

Other motorways built before World War II in Italy were Naples-Pompeii, Florence-Pisa, Padua-Venice, Milan-Turin, Milan-Bergamo-Brescia and Rome-Ostia.

Type B highway (or strada extraurbana principale), commonly but unofficially known as superstrada, is a divided highway with at least two lanes for each direction, paved shoulder on the right, no cross-traffic and no at-grade intersections. Access restrictions on such highways are exactly the same of autostrade, as well as signage at the beginning and the end of the highway (with the only difference being the background color, blue instead of green).

Japan[link]

National expressways (高速自動車国道, Kōsoku Jidōsha Kokudō^?) make up the majority of controlled-access highways in Japan. The network boasts an uninterrupted link between Aomori Prefecture at the northern part of Honshū and Kagoshima Prefecture at the southern part of Kyūshū, linking Shikoku as well. Additional expressways serve travellers in Hokkaidō and on Okinawa Island, although those are not connected to the Honshū-Kyūshū-Shikoku grid. Expressways have a combined length of 8,730 km as of March 2005.^[58]

Korea[link]

Expressways in South Korea were originally numbered in order of construction. Since August 24, 2001, they have been numbered in a scheme somewhat similar to that of the Interstate Highway System in the United States; the icons of the South Korean highways are similar to the US red, white and blue.That's because the people who lead Korea mostly studied at USA.

• Arterial routes are designated by two-digit numbers, with north-south routes having odd numbers, and east-west routes having even numbers. Primary routes (i.e. major thoroughfares) have 5 or 0 as their last digit, while secondary routes end in other digits.

• Branch routes have three-digit route numbers, where the first two digits match the route number of an arterial route. This differs from the American system, whose last two digits match the primary route.

• Belt lines have three-digit route numbers where the first digit matches the respective city's postal code. This also differs from American numbering.

• Route numbers in the range 70–99 are not used in South Korea; they are reserved for designations in the event of Korean reunification.

• The Gyeongbu Expressway kept its Route 1 designation, as it is South Korea's first and most important expressway.

New Zealand[link]

De Lucht Rest Area on the Dutch A2 - A typical rest area with services (fuel, refreshments and toilets). The only access is via the highway that it serves.

The term Motorway in New Zealand encompasses multilane divided freeways as well as narrower 2-4-lane undivided expressways with varying degrees of grade separation; the term Motorway describes the legal traffic restrictions rather than the type of road.^[59]

New Zealand's motorway network is small due to the nation's low population density and low traffic volumes making it uneconomical to build controlled-access highways outside the major urban centres.

New Zealand's first motorway opened in December 1950 near Wellington, running from Johnsonville to Tawa. This 5 km (3.1 mi) motorway now forms the southern part of the Johnsonville-Porirua Motorway and part of State Highway 1.^[60] Auckland's first stretch of motorway was opened in 1953 between Ellerslie and Mount Wellington (between present-day Exit 435 and Exit 438), and now forms part of the Southern Motorway.^[61]

Most major urban areas in New Zealand feature limited-access highways. Auckland, Wellington, Christchurch and Dunedin contain motorways, with only Auckland having a substantial motorway network.

Pakistan[link]

Pakistan has a network of high-quality, international-standard limited access (or access-controlled) Motorways and Expressways, which are maintained and operated by the National Highway Authority. Pakistan has also the largest network of Motorways in South Asia, in August 2009, operational Motorways and Expressways in Pakistan had a combined length of 632 km (393 mi) with another 233 km (145 mi) under construction and further planned.

Pakistan's motorways are part of Pakistan's National Trade Corridor project that aims to link Pakistan's three Arabian Sea ports of Karachi, Port Qasim and Gwadar to the rest of the country and further on with Afghanistan, Central Asia and China.

Pakistan's first motorway, the M2, was inaugurated in November 1997. The M2 is a 367 km (228 mi) long, six-lane motorway that links Pakistan's federal capital, Islamabad, with Punjab's provincial capital, Lahore. Since the completion of the M2, two additional motorways have become operational. These are the 54 km (34 mi) four-lane (with capacity to increase to six lanes) M3 (Pindi Bhattian-Faisalabad), which links the M2 to Faisalabad and the 154 km (96 mi) six-lane M1 (Peshawar-Islamabad). One additional motorway is currently under-construction, the 233 km (145 mi) four-lane (with capacity to increase to six lanes) M4 (Faisalabad-Multan).

Philippines[link]

In the Philippines, there are six controlled-access highways, locally called tollway or expressway, all located on the island of Luzon.

Poland[link]

The highways in Poland are divided into motorways and expressways. As of November 2011, there are 926 kilometres (580 mi) of motorways^[62] (autostrady, singular – autostrada) and 718 km (450 mi) of expressways^[62] (drogi ekspresowe, singular – droga ekspresowa).

Expressways in Poland are limited-access roads which can be dual or single carriageways. As of January 20, 2011 there are 718 km (450 mi) of expressways in Poland. There are about 570 km (350 mi) of expressways in various stages of construction.^[62] The start of an expressway in Poland is marked with sign of white car on blue background, while number sign for an expressway is of red background and white letters, with the letter S preceding a number.

On May 15, 2004 the Regulation of the Council of Ministers (on the network of motorways and express roads) referred to a network of motorways and expressways in Poland totalling about 7,200 km (4,470 mi) (including about 2,000 km (1,240 mi) of motorways).^[63] Regulation from February 2007 added roads S2 and S79 to the list.^[64] Regulation from October 2009 supplemented plans with road S61.^[65] The following table summarizes the planned expressways in accordance with government regulations. Please note the lengths are approximate and are only indicative. As of end of January 2011 there are over 700 km (430 mi) of both single and dual-carriageway expressways in Poland.^[62] There are about 570 km (350 mi) of expressways in various stages of construction.^[62]

South Africa[link]

In South Africa, the term freeway differs from most other parts of the world. A freeway is a road where certain restrictions apply.^[66] The following are forbidden from using a freeway:

• a vehicle drawn by an animal;
• a pedal cycle (such as a bicycle);
• a motor cycle having an engine with a cylinder capacity not exceeding 50 cm³ or that is propelled by electrical power;
• a motor tricycle or motor quadrucycle;
• pedestrians

Drivers may not use hand signals on a freeway (except in emergencies) and the minimum speed on a freeway is 60 km/h (37 mph). Drivers in the rightmost lane of multi-carriageway freeways must move to the left if a faster vehicle approaches from behind to overtake.

Despite popular opinion that "freeway" means a road with at least two carriageways, single carriageway freeways exist, as is evidenced by the statement that "the roads include 1400 km of dual carriageway freeway, 440 km of single carriageway freeway and 5300 km of single carriage main road with unlimited access."^[67] The Afrikaans translation of freeway is snelweg (literally fast road or expressway).

Spain[link]

With 15,152 km (9,415 mi), the Spanish motorway network is the fourth largest in the world by length, after the United States, China and Canada. Autopistas are specifically reserved for automobile travel, so all vehicles not able to sustain at least 60 km/h (37 mph) are banned from them. General speed limits are mandated by the Spanish Traffic Law as 60–120 km/h (37–75 mph). Specific limits may be imposed based on road, meteorologic or traffic conditions. Spanish legislation requires an alternate route to be provided for slower vehicles. Many, but not all, autopistas are toll roads, which also mandates an alternate toll-free route under the Spanish laws.

Thailand[link]

The Thai motorway network is an intercity motorway network that spans 145 kilometres (90 mi). It is to be extended to over 4,000 kilometres (2,500 mi) according to the master plan.

Thailand's motorway network is considered to be separate from Thailand's expressway network, which is the system of usually elevated expressways within Greater Bangkok. Thailand also has a provincial highway network.

The Thai highway network spans over 70,000 kilometres (43,000 mi) across all regions of Thailand. These highways, however, are often dual carriageways with frequent u-turn lanes and intersections slowing down traffic. Coupled with the increase in the number of vehicles and the demand for a limited-access motorway, the Thai Government issued a Cabinet resolution in 1997 detailing the motorway construction master plan. Some upgraded sections of highway are being turned into a "motorway", while other motorways are being purpose-built.

United States[link]

In the United States, a freeway is defined by the federal government's Manual on Uniform Traffic Control Devices as a divided highway with full control of access.^[68] This means two things. First, adjoining property owners do not have a legal right of access,^[69] meaning that they cannot connect their lands to the highway by constructing driveways, although frontage roads provide access to properties adjacent to a freeway in many places. When an existing road is converted into a freeway, all existing driveways must be removed and access to adjacent private lands must be blocked with fences or walls.

Second, traffic on a freeway is "free-flowing". All cross-traffic (and left-turning traffic) is relegated to overpasses or underpasses, so that there are no traffic conflicts on the main line of the highway which must be regulated by traffic lights, stop signs, or other traffic control devices. Achieving such free flow requires the construction of many overpasses, underpasses, and ramp systems. The advantage of grade-separated interchanges is that freeway drivers can almost always maintain their speed at junctions since they do not need to yield to vehicles crossing perpendicular to mainline traffic.

In contrast, an expressway is defined as a divided highway with partial control of access.^[70] Expressways may have driveways and at-grade intersections, though these are usually less numerous than on ordinary arterial roads.

This distinction was apparently^{[citation needed]} first developed in 1949 by the Special Committee on Nomenclature of what is now the American Association of State Highway and Transportation Officials.^[71] In turn, the definitions were incorporated into AASHTO's official standards book, the Manual on Uniform Traffic Control Devices, which would become the national standards book of the U.S. Department of Transportation under a 1966 federal statute. The same distinction has also been codified into the statutory law of eight states: California,^[72] Minnesota,^[73] Mississippi,^[74] Missouri,^[75] Nebraska,^[76] North Dakota,^[77] Ohio,^[78] and Wisconsin.^[79]

However, each state codified the federal distinction slightly differently. California expressways do not necessarily have to be divided, though they must have at least partial access control. For both terms to apply, in Wisconsin, a divided highway must be at least four lanes wide; and in Missouri, both terms apply only to divided highways at least 10 miles (16 km) long that are not part of the Interstate Highway System. In North Dakota and Mississippi, expressways may have "full or partial" access control and "generally" have grade separations at intersections; a freeway is then defined as an expressway with full access control. Ohio's statute is similar, but instead of the vague word generally, it imposes a requirement that 50% of an expressway's intersections must be grade-separated for the term to apply.^[80] Only Minnesota enacted the exact MUTCD definitions, in May 2008.

The term expressway is also used for what the federal government calls "freeways";^[81] Where the terms are distinguished, freeways can be characterized as expressways upgraded to full access control, while not all expressways are freeways.

Examples in the United States of roads which are technically expressways (under the federal definition), but contain the word "freeway" in their names: State Fair Freeway in Kansas, Chino Valley Freeway, Rockaway Freeway in New York, and Shenango Valley Freeway (a portion of U.S. Route 62) in Pennsylvania.

Unlike some countries, not all freeways in the U.S. are part of a single national freeway network (although together with non-freeways, they form the National Highway System). For example, many state highways such as California State Route 99 have significant freeway sections. Many sections of the older United States Numbered Highways network have been upgraded to freeways but have kept their existing U.S. Highway numbers.

See also[link]

	Roads portal
	Canada Roads portal
	U.S. Roads portal

• List of controlled access highway systems
• List of OECD countries by road network size

References[link]