Highway

A highway is a public road meant for cars, trucks, and other vehicles to travel quickly and safely. Highways can be major roads with special rules to keep traffic moving smoothly, like controlled-access highways. In many places, these roads are called by different names such as motorway, Autobahn, autostrada, or autoroute.

A street in Oğuz, Azerbijan

The word “highway” has been used since before the 12th century. The word “high” means “main” — so a highway is often the main road for travel. In places like North America and Australia, big roads may be called state highways or provincial highways, depending on which government takes care of them.

Highways are important because they help people and goods move across long distances. They connect cities, towns, and countries, making travel and trade easier. Because highways are used by many people every day, there are special rules, like the highway code, to keep everyone safe.

Overview

Raccordo autostradale RA3 In Italy, which connects the Tuscan cities of Florence and Siena

Major highways are often named and numbered by the governments that build and maintain them. Australia’s Highway 1 is the longest national highway in the world, stretching over 14,500 kilometers (9,000 miles) and going almost all the way around the continent. China has the largest network of highways, followed closely by the United States. Some highways, like the Pan-American Highway or the European routes, pass through many countries. Certain major highways also include ferry services, such as US Route 10, which crosses Lake Michigan.

In the past, highways were used by people on foot or on horses. Later they were used by carriages, bicycles, and eventually motor cars, thanks to improvements in road construction. In the 1920s and 1930s, many countries invested a lot in building highway systems to help commerce and support national defense.

Big highways that connect cities in busy developed and developing countries often have special features to make them safer and more efficient. These features include fewer places to enter or exit the road, using dual carriageways with multiple lanes, and having grade-separated junctions with other roads and transport ways. These features are commonly found on highways built as motorways (freeways).

Terminology

England and Wales

In England and Wales, a highway is any path that everyone can use without stopping. This can include big roads, small paths, or even private land where people can walk. It doesn’t matter who owns the land — if people can use it, it’s a highway.

Sometimes highways are for cars, and sometimes they are for walking or riding horses. Usually, if a highway is for cars, it’s also for people on foot or horses, but there are exceptions. Some roads are only for certain types of traffic.

Scotland

The I-75/I-85 Downtown Connector in Atlanta, Georgia, in the United States

In Scotland, the rules about highways are similar to England and Wales but use different words. There, a highway is often called a “road.” This means any path people can use, whether it has a toll or not. It includes the sides of the road and any bridges or tunnels on it.

United States

In the United States, a highway is a big, important road meant for cars and other vehicles. These roads usually have numbers given by state or federal transportation departments.

In California, laws say a highway is only for motor vehicles, but courts have decided that some places, like canals in Venice, can also be considered highways and get state money for upkeep.

History

See also: Road and History of road transport

The Italian Autostrada dei Laghi ("Lakes Highway" in the 1950s; now parts of the Autostrada A8 and the Autostrada A9), the first controlled-access highway ever built in the world

Large highway systems began in the 1900s when more people started using cars. The first major road built just for cars was in New York, called the Long Island Motor Parkway. It opened in 1911 and had special features like curved turns and safety barriers.

Italy built the world's first highway just for fast traffic and cars in 1924, linking Milan to nearby lakes. Germany started building its famous Autobahn network in the 1930s, creating the first high-speed road system. In the United States, big plans for national highways started in the 1920s, with a major building program beginning in 1956 to create many miles of interconnected roads for cars. The United Kingdom also began building its own special roads for cars in the late 1950s.

Design

Classification

In the United States, the Federal Highway Administration groups highways into different types based on how they are used. These types include major roads for fast travel, smaller roads for local areas, and roads that connect these two types.

Other countries, like those in Europe, also have their own ways of grouping roads. The European Commission uses categories such as roads for long-distance travel and roads that help connect nearby areas.

Metrics

There are ways to measure how well highways work for drivers. One way is to look at the speed drivers choose when they are alone on the road with no traffic lights, but still facing some limits like pedestrians. Another way is to look at the average speed cars move at, which is usually a bit slower. There is also a way to measure the actual speed people travel at, which helps decide how well the road works for traffic.

Preservation of highway functions

As towns and cities grow, highways can sometimes lose their purpose. To keep them working well, special designs are used. These designs help balance how easy it is to get to places and how fast people can travel. Some highways also have special roads nearby to keep traffic moving smoothly.

Social effects

The construction of Harbor Freeway, and its subsequent displacement of homes in Los Angeles, California.[citation needed]

Highways can make travel faster for people going to work, shopping, or fun places. They help move goods more easily. But building new roads can sometimes cause traffic to get worse later if not planned well. This happens because more people start using their cars when they see there is more space to drive.

When highways are built through towns, it can make it harder for neighbors to stay close and for people to get around easily. In some places, this has led to lower home values and poorer housing. Sadly, in the past, some highway plans unfairly affected certain groups of people more than others. Today, many cities are taking down old highways to create parks and spaces where people can live and work instead.

Economic effects

Main article: Transport economics

A taxiway crossing the Autobahn, near Leipzig

When we think about roads and highways, we look at how many trips people make and how far they travel. We also consider how much it costs, including both money and time spent traveling.

More roads can bring both good and bad effects. Good effects include better emergency services and higher land values. However, there are also bad effects such as air and noise pollution, safety risks, and traffic jams. Highways can also affect the environment and make it hard to plan for the future.

Studies show that more highways can lead to more new inventions and changes in where people live and work.

Environmental effects

Main article: Environmental impacts of roads

Noise, light and air pollution are negative environmental effects highways can have on their surroundings.

Highways can affect the environment in several ways. They are major sources of noise and air pollution, especially in areas close to the highway. Noise increases with speed, and strategies exist to reduce sound levels near homes and other sensitive places. While highways might produce fewer emissions than smaller roads with many stops, the high amount of traffic can lead to higher concentrations of air pollutants nearby.

Highways can also split natural habitats, encourage cities to spread out, and sometimes even increase traffic congestion. They may reduce the use of public transport, which can lead to more pollution. Some newer highways include special lanes for cars carrying several people to reduce the number of vehicles on the road. Wildlife crossings are also being built to help animals safely cross highways.

In the long term, highways might help prevent forest fires and support the growth of larger cities, which can lead to changes in how people live and affect the environment.

Road traffic safety

Main article: Road traffic safety

Road traffic safety looks at how to keep roads and streets safe and reduce harm from accidents. This includes designing and building better roads, making sure vehicles are safe, and teaching drivers and everyone else how to use the roads properly.

A report from the World Health Organization in 2004 found that many people, including a lot of young people aged 10 to 19, were hurt or killed in road accidents each year, especially in places where roads and cars are not as well managed. Simple safety steps could help save many lives.

Statistics

The United States has the largest network of highways in the world. This includes the Interstate Highway System and the United States Numbered Highway System. These highways connect most major cities across every state.

China has the second-largest highway network, with over 3,500,000 kilometres of roads. Its expressway system is the longest in the world and keeps growing.

The Pan-American Highway is the longest international highway, stretching nearly 25,000 kilometres across many countries in the Americas. However, there is a break in the road in Panama where the land is too difficult for building.

Canada’s Trans-Canada Highway is the longest highway within one country from one point to another. It runs across Canada, connecting many big cities from coast to coast.

Australia’s Highway 1 is the longest highway that loops around a country. It goes almost all the way around Australia’s coastline, linking most of the capital cities.

The Cross Bronx Expressway in New York, United States uses asphalt and concrete pavement, both of which are popular road surfaces on highways.

The busiest highway is Highway 401 in Ontario, Canada, where over 500,000 vehicles pass each day in some parts of Toronto.

In Houston, Texas, the Katy Freeway (part of Interstate 10) has up to 26 lanes in some sections.

In San Diego, California, a part of Interstate 5 has 22 lanes for regular traffic.

The Karakoram Highway between Pakistan and China is the highest international highway, reaching about 4,700 metres above sea level.

In India, National Highway 5 reaches about 4,900 metres, with an even higher road branching off of it.

Bus lane

South Korea

In South Korea, a special road just for buses started in February 1995 between the northern end and Sintanjin for big holidays. Then, on July 1, 2008, the rule for buses between Seoul and Osan changed to every day from 6 a.m. to 10 p.m. Later, on October 1, the times changed to 7 a.m. to 9 p.m. on weekdays and 9 a.m. to 9 p.m. on weekends.

Highway bus lane on Gyeongbu Expressway in South Korea

There are different types of lines:

On dotted lines, cars that aren’t buses can turn right and pass temporarily to join the road. But when the bus lane is closed, it’s like normal dotted lines.
On double-dotted lines, only buses can use the road even outside busy times. Other cars can pass for right turns, but when there are no buses, it’s like normal dotted lines.
On solid lines, only buses can drive, but the rule changes depending on the time and day. When there are no buses, it’s like a normal solid line.
On double lines, buses can drive even outside busy times. If there are no cars, it’s like solid white lines.

Hong Kong

In Hong Kong, some big roads have special lanes for buses to help with traffic jams.

Philippines

Big cities like Metro Manila in the Philippines have many traffic problems. The government made special bus lanes on roads, like on the Epifanio delos Santos Avenue, to help with congestion.

Examples of highways with bus lanes
Country	Highway	Bus lanes (km)	Section
Australia	M2 Hills Motorway	21.4	Abbott Road–Beecroft Road (Sydney)
Australia	Eastern Freeway	11	Hoddle Street–Doncaster Park & Ride (Melbourne)
Canada	Don Valley Parkway	0.458	Shoulder converted as bypass lane from Lawrence Avenue East to York Mills Road
Canada	Ontario Highway 417	7	Eagleson Road–Ontario Highway 417 (Ottawa)
Canada	Ontario Highway 403	6	Mavis Road–Winston Churchill Boulevard (Mississauga)
Hong Kong	Tuen Mun Road	19.4
India	National Highway (India)	19	30 lanes Road, (Mumbai)
Netherlands	A1 motorway (Netherlands)	119	End of A6-Vechtbrug (Muiden)
South Korea	Gyeongbu Expressway	137.4	Hannam IC (Seoul) ~ Sintanjin IC (Daejeon)
United States	El Monte Busway	19	Shared use Busway between Interstate 10 between Los Angeles Union Station and El Monte station (Los Angeles)