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A highway is any public or private [[road]] or other public way on land. It is used for major roads, but also includes other public roads and public tracks. In some areas of the United States, it is used as an equivalent term to [[controlled-access highway]], or a translation for ''
autobahn'', ''
autoroute'', etc.
According to
Merriam Webster, the use of the term predates the 12th century. According to
Etymonline, "high" is in the sense of "main".
In
North American and
Australian English, major roads such as controlled-access highways or
arterial roads are often
state highways (Canada:
provincial highways). Other roads may be designated "
county highways" in the US and
Ontario. These classifications refer to the level of government (state, provincial, county) that maintains the roadway.
In
British English, "highway" is primarily a legal term. Everyday use normally implies roads, while the legal use covers any route or path with a public right of access, including
footpaths etc.
The term has led to several related derived terms, including
highway system,
highway code,
highway patrol and
highwayman.
Overview
Major highways are often named and numbered by the governments that typically develop and maintain them. Australia's
Highway 1 is the longest national highway in the world at over and runs almost the entire way around the continent. China has the world's largest network of highways followed closely by the United States of America. Some highways, like the
Pan-American Highway or the
European routes, span multiple countries. Some major highway routes include
ferry services, such as
US Route 10, which crosses
Lake Michigan.
Traditionally highways were used by
people on foot or on
horses. Later they also accommodated
carriages,
bicycles and eventually
motor cars, facilitated by advancements in
road construction. In the 1920s and 1930s, many nations began investing heavily in progressively more modern highway systems to spur
commerce and bolster national defence.
Major modern highways that connect cities in populous
developed and
developing countries usually incorporate features intended to enhance the road's capacity, efficiency, and safety to various degrees. Such features include a
reduction in the number of locations for user access, the use of
dual carriageways with two or more lanes on each carriageway, and
grade-separated junctions with other roads and modes of transport. These features are typically present on highways built as ''
motorways'' (''
freeways'').
Terminology
England and Wales
The general legal definition deals with right of use not the form of construction; this is distinct from e.g. the popular use of the word in the US. A highway is defined in English
common law by a number of similarly-worded definitions such as "a way over which all members of the public have the right to pass and repass without hindrance" usually accompanied by "at all times"; ownership of the ground is for most purposes irrelevant thus the term encompasses all such ways from the widest trunk roads in public ownership to the narrowest footpath providing unlimited pedestrian access over private land.
A highway might be open to all forms of lawful land traffic (i.e. vehicular, horse, pedestrian) or limited to specific types of traffic or combinations of types of traffic; usually a highway available to vehicles is available to foot or horse traffic, a highway available to horse traffic is available to pedestrians but exceptions can apply usually in the form of a highway only being available to vehicles or subdivided into dedicated parallel sections for different users.
A highway can share ground with a private right of way for which full use is not available to the general public as often will be the case with farm roads which the owner may use for any purpose but for which the general public only has a right of use on foot or horseback. The status of ''highway'' on most older roads has been gained by established public use while newer roads are typically ''dedicated'' as highways from the time they are adopted (taken into the care and control of a council or other public authority). In England and Wales, a public highway is also known as "''The Queen's Highway''".
The core definition of a highway is modified in various legislation for a number of purposes but only for the specific matters dealt with in each such piece of legislation. This is typically in the case of bridges, tunnels and other structures whose ownership, mode of use or availability would otherwise exclude them from the general definition of a highway, examples in recent years are commonly toll bridges and tunnels which have the definition of ''highway'' imposed upon them (in a legal order applying only to the individual structure) to allow application of most traffic laws to those using them but without causing all of the general obligations or rights of use otherwise applicable to a highway.
What is called 'highway' in the context of motor vehicles, is called 'motorway' in the UK context.
Scotland
Scots law is similar to English law with regard to highways but with differing terminology and legislation. What is defined in England as a ''highway'' will often in Scotland be what is defined by s.151
Roads (Scotland) Act 1984 (but only "in this act" although other legislation could imitate) simply as a road, that is :-
*"any way (other than a waterway) over which there is a public right of passage (by whatever means
nd whether subject to a toll or not and includes the road’s verge, and any bridge (whether permanent or temporary) over which, or tunnel through which, the road passes; and any reference to a road includes a part thereof; "
The word ''highway'' is itself no longer a statutory expression in Scots law but remains in common law.
United States
In American law, the word "highway" is sometimes used to denote any public way used for travel, whether a "road, street, and parkway";
however, in practical and useful meaning, a "highway" is a major and significant, well-constructed road that is capable of carrying reasonably heavy to extremely heavy traffic. Highways generally have a route number designated by the state and federal departments of transportation.
California Vehicle Code, Sections 360, 590, define a "highway" as only a way open for use of motor vehicles, but the California Supreme Court has held that "the definition of 'highway' in the Vehicle Code is used for special purposes of that act," and that canals of the Los Angeles neighborhood of
Venice, California, are "highways" that are entitled to be maintained with state highway funds.
Smaller roads may be termed
byways.
History
Modern highway systems developed in the 20th century as the
automobile gained popularity. The world's first
limited access road was constructed on Long Island New York in the United States known as the
Long Island Motor Parkway or the Vanderbilt Motor Parkway. It was completed in 1911.
In Italy the Milano-Varese autostrada was opened in 1924.
Construction of the Bonn–Cologne
autobahn began in 1929 and it was opened in 1932 by the mayor of
Cologne,
Konrad Adenauer.
In the US, the
Federal Aid Highway Act of 1921 (Phipps Act) enacted a fund to create an extensive highway system. In 1922, the first blueprint for a national highway system (the
Pershing Map) was published. The
Federal Aid Highway Act of 1956 allocated $25 billion for the construction of the
Interstate Highway System over a 20-year period.
In
Great Britain, the
Special Roads Act 1949 provided the legislative basis for roads for restricted classes of vehicles and non-standard or no speed limits applied (later mostly termed
motorways but now with speed limits not exceeding 70 mph); in terms of general road law this legislation overturned the usual principle that a road available to vehicular traffic was also available to horse or pedestrian traffic as is usually the only practical change when non-motorways are reclassified as ''special roads''. The first section of motorway in the UK opened in 1958 (part of the M6 motorway) and then in 1959 the first section of the
M1 motorway.
Social effects

Reducing travel times relative to city or town streets, modern highways with limited access and grade separation create increased opportunities for people to travel for business, trade or pleasure and also provide trade routes for goods. Modern highways reduce commute and other travel time but additional road capacity can also release
latent traffic demand. If not accurately predicted at the planning stage, this extra traffic may lead to the new road becoming congested sooner than would otherwise be anticipated by considering increases in vehicle ownership. More roads allow drivers to use their cars when otherwise alternatives may have been sought, or the journey may not have been made, which can mean that a new road brings only short-term mitigation of traffic congestion.
Where highways are created through existing communities, there can be reduced
community cohesion and more difficult local access. Consequently, property values have decreased in many cutoff neighborhoods, leading to decreased housing quality over time.
Economic effects
In transport,
demand can be measured in numbers of journeys made or in total distance travelled across all journeys (e.g.
passenger-kilometres for
public transport or vehicle-kilometres of travel (VKT) for
private transport).
Supply is considered to be a measure of capacity. The
price of the good (travel) is measured using the
generalised cost of travel, which includes both
money and
time expenditure.

The effect of increases in supply (capacity) are of particular interest in transport economics (see
induced demand), as the potential environmental consequences are significant (see ''externalities'' below).
In addition to providing benefits to their users, transport networks impose both
positive and
negative externalities on non-users. The consideration of these externalities—particularly the negative ones—is a part of transport economics. Positive externalities of transport networks may include the ability to provide
emergency services, increases in
land value and
agglomeration benefits. Negative externalities are wide-ranging and may include local
air pollution,
noise pollution,
light pollution,
safety hazards,
community severance and
congestion. The contribution of transport systems to potentially hazardous
climate change is a significant negative externality which is difficult to evaluate quantitatively, making it difficult (but not impossible) to include in transport economics-based research and analysis. Congestion is considered a negative
externality by economists.
A 2016 study finds that for the United States "a 10% increase in a region's stock of highways causes a 1.7% increase in regional patenting over a five-year period."
Environmental effects

Highways are extended
linear sources of
pollution.
Roadway noise increases with operating speed so major highways generate more noise than
arterial streets. Therefore, considerable
noise health effects are expected from highway systems.
Noise mitigation strategies exist to reduce sound levels at nearby
sensitive receptors. The idea that highway design could be influenced by
acoustical engineering considerations first arose about 1973.
Air quality issues: Highways may contribute fewer
emissions than arterials carrying the same vehicle volumes. This is because high, constant-speed operation creates an emissions reduction compared to vehicular flows with stops and starts. However, concentrations of air pollutants near highways may be higher due to increased traffic volumes. Therefore, the risk of exposure to elevated levels of air pollutants from a highway may be considerable, and further magnified when highways have
traffic congestion.
New highways can also cause
habitat fragmentation, encourage
urban sprawl and allow human intrusion into previously untouched areas, as well as (counterintuitively) increasing congestion, by increasing the number of intersections.
They can also reduce the use of
public transport, indirectly leading to greater pollution.
High-occupancy vehicle lanes are being added to some newer/reconstructed highways in the United States and other countries around the world to encourage
carpooling and mass-transit. These lanes help reduce the number of cars on the highway and thus reduces pollution and traffic congestion by promoting the use of carpooling in order to be able to use these lanes. However, they tend to require dedicated lanes on a highway, which makes them difficult to construct in dense urban areas where they are the most effective.
To address habitat fragmentation,
wildlife crossings have become increasingly popular in many countries. Wildlife crossings allow animals to safely cross human-made barriers like highways.
Road traffic safety
Road traffic safety describes the safety performance of roads and streets, and methods used to reduce the harm (deaths, injuries, and property damage) on the highway system from
traffic collisions. It includes the design, construction and regulation of the
roads, the
vehicles used on them and the training of drivers and other road-users.
A report published by the
World Health Organization in 2004 estimated that some 1.2m people were killed and 50m injured on the roads around the world each year and was the leading cause of death among children 10–19 years of age.
The report also noted that the problem was most severe in developing countries and that simple prevention measures could halve the number of deaths.
For reasons of clear data collection, only harm involving a road vehicle is included.
A person tripping with fatal consequences or dying for some unrelated reason on a public road is not included in the relevant statistics.
Statistics

The United States has the world's largest network of highways, including both the
Interstate Highway System and the
United States Numbered Highway System. At least one of these networks is present in every state and they interconnect most major cities.
China's highway network is the second most extensive in the world, with a total length of about .
China's
expressway network is the longest Expressway system in the world, and it is quickly expanding, stretching some at the end of 2011. In 2008 alone, expressways were added to the network.
;Longest international highway: The
Pan-American Highway, which connects many countries in the
Americas, is nearly long . The Pan-American Highway is discontinuous because there is a
significant gap in it in southeastern
Panama, where the rainfall is immense and the terrain is entirely unsuitable for highway construction.
;Longest national highway (point to point): The
Trans-Canada Highway has one main route, a northern route through the
western provinces, and several branches in the
central and
eastern provinces. The main route is long alone, and the entire system is over long. The TCH runs east-west across southern Canada, the populated portion of the country, and it connects many of the major urban centres along its route crossing all provinces, and reaching nearly all of their capital cities.
The TCH begins on the east coast in
Newfoundland, traverses that island, and crosses to the mainland by ferry. It crosses the
Maritime Provinces of eastern Canada with a branch route serving the province of
Prince Edward Island via a ferry and bridge. After crossing the remainder of the country's mainland, the highway reaches
Vancouver,
British Columbia on the
Pacific coast, where a ferry continues it to
Vancouver Island and the provincial capital of
Victoria. Numeric designation is the responsibility of the provinces, and there is no single route number across the country.
;Longest national highway (circuit): Australia's
Highway 1 at over . It runs almost the entire way around the country's coastline. With the exception of the Federal Capital of
Canberra, which is far inland, Highway 1 links all of Australia's capital cities, although Brisbane and Darwin are not directly connected, but rather are bypassed short distances away. Also, there is a ferry connection to the island state of
Tasmania, and then a stretch of Highway 1 that links the major towns and cities of Tasmania, including
Launceston and
Hobart (this state's capital city).
;Largest national highway system: The United States of America has approximately of highway within its borders .
;Busiest highway:
Highway 401 in
Ontario, Canada, has volumes surpassing an average of 500,000 vehicles per day in some sections of Toronto .
;Widest highway (maximum number of lanes): The
Katy Freeway (part of
Interstate 10) in
Houston,
Texas, has a total of 26 lanes in some sections . However, they are divided up into general use/
frontage roads/
HOV lanes, restricting the traverse traffic flow.
;Widest highway (maximum number of through lanes):
Interstate 5 along a section between
Interstate 805 and
California State Route 56 in
San Diego, California, which was completed in April 2007, is 22 lanes wide.
;Highest international highway: The
Karakoram Highway, between Pakistan and China, is at an altitude of .;
;Highest national highway:
National Highway 5, in India, connecting
Amritsar in
Punjab with
Manali in
Himachal Pradesh &
Leh in
Ladakh, reaches an approximate altitude of .. The highest motorable road passes through Umling La at an altitude of falls under the branch highway connecting National Highway 5 in India.
Bus lane

Some countries incorporate
bus lanes onto highways.
South Korea
In
South Korea, in February 1995 a
bus lane (essentially an
HOV-9) was established between the northern terminus and Sintanjin for important holidays and on 1 July 2008 bus lane enforcement between Seoul and Osan (Sintanjin on weekends) became daily between 6 a.m. and 10 p.m. On 1 October this was adjusted to 7 a.m. to 9 p.m. weekdays, and 9 a.m. to 9 p.m. weekends.
Hong Kong
In
Hong Kong, some highways are set up with bus lanes to solve the traffic congestion.
Philippines
Traffic congestion was a principal problem in major
roads and
highways in the
Philippines, especially in
Metro Manila and other major cities. The government decided to set up some bus lanes in Metro Manila like in the
Epifanio delos Santos Avenue.
Gallery
File:Spaghetti-Junction-Crop.jpg|Gravelly Hill Interchange in Birmingham, England
File:Autogrill-greece-A1 2009.jpg|A1 Motorway near Athens, Greece with rest area above
File:A1 (A14 Bologna B.go Panigale).JPG|The ten-lane Highway A1 near Bologna, Italy
File:S1 1.JPG|A Polish expressway in Bielsko-Biała
File:5, 70870 Kuopio, Finland - panoramio.jpg|National road 5 in Kuopio, Finland
File:E4 Nyköpingsbro.jpg|E4 motorway with rest area outside Nyköping, Sweden
File:401 widest point.jpg|Highway 401 with collector and express lanes in Mississauga, Ontario, Canada
File:Garching_Bundesautobahn_9.jpg|Multi-lane Autobahn 9 in Munich, Germany
File:Pan-American Highway-Mancora, Peru.jpg|The Pan-American Highway where it serves as the main street in Máncora, Peru
File:PRC Expressway.jpg|A typical expressway in China
File:S85(Guizhou) Duyun Direction Exit 332 close to G75.jpg|An expressway exit in Guizhou, China
File:North Lantau Highway near Citygate (Hong Kong).jpg|North Lantau Highway in Hong Kong
File: Delhi Noida Direct flyway (Uttar Pradesh - 2011-06-18).jpg|A typical expressway in India
File:Delhi Gurgaon Toll Gate.jpg|32-lane toll plaza at Delhi-Gurgaon Expressway in Gurgaon, India
File:HIghway Chennai Bangalore.jpg|Chennai-Bangalore Highway
File:Express highway.jpg|Mumbai Pune Expressway, India
File:Kordestan-Resalat-Hakim.jpg|A highway interchange in Tehran, Iran
File:Tokyo EXP way.JPG|The Metropolitan Expressway in Tokyo, Japan
File:Kuwait highway.jpg|A highway in Kuwait City
File:2007 08 21 China Pakistan Karakoram Highway Khunjerab Pass IMG 7295.jpg|Karakoram Highway, Pakistan
File:FvfValenzuela1372 37.JPG|North Luzon Expressway, the Philippines
File:Jisu IC in Namhae Expressway.JPG|Namhae Expressway in Jinju, South Korea
File:The-Expressway_at_Ja-ela.jpg|Ja-Ela Interchange in the Airport Expressway(E03) in Ja-Ela, Sri Lanka
File:Dubai Roads on 1 May 2007.jpg|3/4 highway interchange in Dubai, United Arab Emirates
File:Quoclo1Amoi.JPG|National Route 1A near Từ Sơn, Vietnam
See also
General
*
Bypass route
*
Controlled-access highway
*
Divided highway (dual carriageway)
*
Freeway
*
Highway systems by country
*
Highwayman
*
Infrastructure
*
Limited-access road
*
List of roads and highways
*
Motorway
*
Parkway
*
Passing lane
*
Ring road
*
Road
*
Road junction
*
Road safety
*
Road transport
*
Roadway air dispersion modeling
*
Roadway noise
*
Toll road
*
Undivided highway (single carriageway)
By country
*
Algeria East–West Highway
*
Autobahns of Austria
* ''
Autoput'' and ''
Autocesta''
* ''
Rodovia''
* ''
Avtomagistrala''
*
Highways in Canada
*
Expressway
* ''
Autocesta''
* ''
Dálnice''
* ''Autostrada''
* ''
Autoroute''
*
Autobahns of Germany
* ''
Aftokinitodromos''
* ''
Autópálya''
*
National Highways and
Expressways
*
Motorway
*
List of highways in Israel
*
Autostrade of Italy
* ''
Kōsokudōro''
* ''
Lebuhraya''
* ''
Autopista de Carretera Federal''
* ''
Autoroute''
* ''
Avtopat''
* ''
Motorvei''
*
Motorways and
National Highways of Pakistan
* ''
Autoestrada''
[Notable for the introduction of the world's first electronic toll collection system, the ''Via Verde''.]
*
Russian federal highways
* ''
Autoput''
* ''
Avtocesta''
* ''
Autopista''
* ''
Motorväg''
*
Autobahns of Switzerland
*
Freeways in Taiwan
*
State Highways (Ukraine)
*
Highways in the United Kingdom
* ''
Autofamba''
References
External links
Full list of Euroroutes with distancesThe Greenroads Rating SystemProposed Trans-Global HighwayEuroroutes with distancesOntario Super Highway Program (June 19, 2011)Video of Highway 401 through Greater Toronto
{{Road types
Category:Road infrastructure
Category:Types of roads