Nomenclature
The terms used for various types of highways (such as autobahn, autoroute, expressway, freeway, and motorway) 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.
Social and Environmental Effects
By reducing travel times relative to arterial streets, highways have a positive effect upon balance of leisure or productive time through reduced commute and other travel time. However, highways have criticisms, partially due to being an extended linear source of pollution:
Community cohesion: Where highways are created through existing communities, there can be reduced community cohesion and more difficult local access.
Roadway noise: Highways generate more roadway noise than arterial streets due to the higher operating speeds. 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 emission 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 cause habitat fragmentation and allow human intrusion into previously untouched areas.
Unit 10 Motorway
Motorway symbol in the UK, France and Ireland.
A motorway (in the United Kingdom, New Zealand, Pakistan, some other Commonwealth nations and Ireland) is both a type of road and a classification or designation. 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. In North America, the English terms freeway and expressway (including autoroutes) are used as a type of road, not necessarily as a classification type. Many highways are maintained throughout the United States as part of the Interstate Highway System. These highways are generally similar to motorways in purpose and quality.
Regulations and Features
A Sunday in April 2004 at 5 p.m. on Britain's busy M25
In Ireland and the UK, motorways are denoted by blue signage and an M-prefixed or suffixed road number.
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. The road surface is generally tarmac (“black top”) or concrete (“white top”). Other features are crash barriers, cat’s eyes and, increasingly, textured road markings (a similar concept to rumble-strips).