Motorway

A motorway (United Kingdom, Republic of Ireland, and some Commonwealth nations) is both a type of road and a classification. Motorways may also be regarded as 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, usually with two lanes in each direction and grade-separated access.

Equivalent terms in other countries include autoroute, Autobahn, freeway.

Regulations

For a road to be classified as motorway a number of conditions must be fulfilled. The following conditions apply in the UK and the Republic of Ireland:

• Motorways must be accessed at junctions by slip-roads off the sides of the main thorough-fare;
• 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 central reservation must remain unbroken (a noted exception being the Aston Expressway in Birmingham, which has none);
• Emergency phones must be provided at a regular distance;
• The start and end of a motorway must have signposted entry and exit points.

Most of these rules are occasionally broken!

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 in the UK and the Republic of Ireland are of near-motorway quality, but are not classified as such (generally for breaking the above rules). These are referred to as dual-carriageways, which may be subject to a lower speed limit.

In both countries, motorways are denoted by blue signage (and an M-prefixed road number). Speed limits are generally higher than on ordinary roads, with an overall limit of 70 mph (113 km/h) for cars in both the UK and the Republic. 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 (inside lanes) are intended for general driving, while the outer lanes are intended for overtaking (passing) slower moving vehicles.

Roads in the Republic of Ireland will however, have metric speed limits imposed from 20 January 2005 to conform to both European convention and existing directional signage (metric since 1970s). It is likely that the speed limit for motorways in Ireland will then be slightly increased to 120 km/h (75 mph).

The Conservative Party have proposed increasing the UK motorway speed limit to 80 mph, should they get into power at the next 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.

Unlike in some other countries, drivers are not permitted to pass on the inside unless traffic in the 'faster' lanes is stationary. With a touch of black humour, the practice is popularly known as undertaking. Learner drivers, pedestrians, cyclists and underpowered vehicles (e.g. small scooters) are generally banned from motorways and a 'minimum speed limit' may apply.

Features

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. A white line (or in the Republic of Ireland, a dashed 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 manoeuvres.

Other features are crash-barriers, cat's eyes and increasingly, textured road markings (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. 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 M50 around Dublin.

In Britain there are plans to upgrade many motorways as well as 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 Euros in such projects in the next ten years.

The newest UK motorway to open was the M6 Toll bypassing Birmingham and Wolverhampton in 2004, which is also the only completely toll motorway in England. There are other tolled motorways (the M4 and M48), but they are used over the Severn Bridges.

See also

• List of motorways in the United Kingdom
• Roads in Ireland
• Freeway (includes links to motorways around the world)
• UK topics