The OECD has defined a motorway as:

French Equivalent: Autoroute

Road, specially designed and built for motor traffic, which does not serve properties bordering on it, and which:

:(a) is provided, except at special points or temporarily, with separate carriageways for the two directions of traffic, separated from each other, either by a dividing strip not intended for traffic, or exceptionally by other means;

:(b) does not cross at level with any road, railway or tramway track, or footpath;

:(c) is specially sign-posted as a motorway and is reserved for specific categories of road motor vehicles.

Entry and exit lanes of motorways are included irrespectively of the location of the sign-posts. Urban motorways are also included.

Motorways are identical to freeways as a road type, and comparable to the United States's Interstate Highway as a classification.

In English-speaking countries the term is used in the United Kingdom, some parts of Australia, New Zealand, Pakistan, some other Commonwealth nations, and Ireland (a motorway is also called a mótarbhealach (plural: mótarbhealaí) in Irish). In Ireland, a road built to motorway standard, but without the designation (and the regulations and traffic restrictions resulting from that designation), is known as a High-quality dual carriageway.

Regulations and features

In Ireland, Hungary and the UK, motorways are denoted by an 'M', prefixed (e.g. M1) or suffixed (e.g. A1) road number and blue signage, distinguishing them from A-roads or N-roads, which are signed in green. This is at odds with some countries elsewhere in Europe, where the colours are reversed. In New Zealand, motorways are distinguished from regular state highways with the word 'Motorway' on entrance signage. New Zealand's motorways had green signage while everywhere else had black, until green signage was spread to the entire State Highway network by Transit New Zealand.

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/aquaplaning. The road surface is generally asphalt concrete (popularly referred to as tarmac) or portland cement concrete. Other features are crash barriers, cat's eye and, increasingly, textured road markings (a similar concept to rumble-strips).

Common criteria

For a road to be classified as motorway the OECD conditions described above must apply. The implications of these conditions include:

• Accessed at junctions by slip roads off the sides of the main carriageway or 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 seldom neccessary except at toll booths and to control the number of vehicles entering the motorway from the slip road during busy periods) - see ramp meter;
• Certain types of transport are banned, typically pedestrians, bicycles, learner driver, horses, agricultural vehicles, underpowered vehicles (e.g. small scooter, invalid carriages). In the Republic of Ireland, the "Motorway Ahead" sign at every motorway junction lists the excluded classes of vehicles (this sign was also formerly used in the United Kingdom - from which the Irish version is based - but has been almost entirely phased out). In the UK, the last junction a road becomes a motorway is signed for 'prohibited traffic'. In most Australian states, a sign for "Motorway Entrance" or "Freeway Entrance" was put at the start of these roads, but these too are being phased out. In New Zealand, a no pedestrians and no cycles sign precede the "Motorway Begins" sign.

In the UK and the Republic of Ireland there are further restrictions:

• The central reservation with a continuous crash barrier (an exception being the Aston Expressway in Birmingham which has an empty lane instead and a section of the M40 in Warwickshire, with an unusually wide grass verge separating the carriageways). With effect from January 2005 and based primarily on safety grounds, the UK’s Highways Agency's policy is that all new motorway schemes are to use high containment concrete step barriers in the central reserve. All existing motorways will introduce concrete barriers into the central reserve as part of ongoing upgrades and through replacement as and when these systems have reached the end of their useful life. This change of policy applies only to barriers in the central reserve of high speed roads and not to verge side barriers. Other routes will continue to use steel barriers. The Republic of Ireland has similarly introduced concrete barriers instead of its former policy of wide grass medians (the UK and Ireland share the same Design Manual for Roads and Bridges).
• Emergency telephones (which connect directly to the police, except in England where they connect you directly to the nearest Highways Agency Regional Control Centre who will send either their own officers (HATO's) or other emergency services as required) are provided at a regular intervals (in the UK emergency telephones are situated at intervals of 1 mile, and at 2km in Ireland)
• no roundabouts apart from at the start and finish (some exceptions)
• Hard shoulder available most of the time
• Other roads are connected at motorway interchanges only. No roads join at any other point except for maintenance access.
• Most junctions are numbered

Note that these only apply to roads directly designated as motorways. Roads may also be indirectly designated as such, see Inheritance below.

Traffic on a motorway is required to keep moving, except in exceptional circumstances (cases where traffic queues have built up, the vehicle has broken down, or the driver has been instructed to stop by a police officer). A minimum speed limit of 50km/h applies in the Republic of Ireland.

A motorway in the UK, whether by design or inheritance, must have a Statutory Instrument (SI) defining a stretch of road and sliproads as a special road under the Highways Act 1980. In the Republic of Ireland, a Motorway Scheme must be made under the Roads Act 1993 prior to the road's construction. Alternatively, a Statutory Instrument defining the stretch of road as a motorway may also be made under the Roads Act 2007, however this process may only be used for high-quality dual carriageways either open, in planning, or under construction on the day the Act was signed into law.

Speed limits

Motorway safety is significantly higher than that of other roads, and the speed limits correspondingly higher, although some types of vehicle, such as heavy goods vehicles, may be subject to lower limits.

In the United Kingdom the speed limit for motorways and some dual-carriageways is . Many HGVs are restricted to . UK motorways originally had no speed limit, and were designed for traffic travelling up to . Although the design speed of 100 mph remains, the majority of UK motorways and dual carriageways are now subject to the national speed limit of 70 mph for motorcars and motorcycles; some may have lower limits for various local reasons. A UK Department for Transport (DfT) study at several sites in 2006 showed that over half of all motorway traffic was travelling in excess of this limit. In 2004 the Conservative Party proposed increasing the motorway speed limit to on some stretches, although this did not appear in their 2005 election manifesto. The Association of British Drivers supported the proposal, as they claimed it more closely represents the normal (and, they claim, safe) driving practice of the majority of motorway users.

In Ireland the speed limit for motorways and some dual-carriageways is 120 km/h (75 mph). In certain sections of motorway the speed limit is 100 km/h, however the vast majority of the network is 120 km/h.

In Pakistan, the speed limit on motorway was 140 km/h (87 mph) for light vehicles and 120 km/h (75 mph) for heavy vehicles; however later it was restricted to 120 km/h (75 mph) for light vehicles and 110 km/h (68 mph) for heavy vehicles.

In New Zealand the speed limit on motorways and other dual carriageways is normally the top limit for state highways, 100 km/h (62 mph), with restrictions in some areas, such as the Auckland Harbour Bridge and Central Motorway Junction (both have limits of 80 km/h (50 mph)).

In Turkey, the speed limit on motorways is 120 km/h.

Germany has no general speed limit on its motorways (Autobahn); there are only particular speed limits e.g. at dangerous sections, sections with traffic jam hazards, road works or at some motorways through cities.

In Poland, it is discussed in the Sejm to raise the expressway speed limits from 110 km/h (70 mph) to 120 km/h (75 mph), and on motorways from 130 km/h (81 mph) to 140 km/h (89 mph)

In Italy the speed limit on motorways generally is 130 km/h (80 mph), however it is 150 km/h (93 mph) on some good 3+3 lane motorways.

In France and Luxembourg the speed limit on motorways generally is 130 km/h, however it is 110 km/h in rain or if there is water on the road.

The lowest speed limit on motorways in any country in Europe is Norway, where the limit usually is 100 km/h (the basic speed limit is 80, but most motorways have been given 100 as limit).

In Hong Kong the speed limit ranges between 70 to 100 km/h. Only one expressway, the North Lantau Expressway that connects the Chek Lap Kok International Airport, has a speed limit at 110 km/h.

Lanes

Most motorway carriageways comprise a main running surface, with a hard shoulder along one edge, and a median or central reservation separating it from the other carriageway along the other edge. The hard shoulder is generally provided for use in emergencies, such as breakdowns, only. However the M42 in the UK has a system whereby a small section of the hard shoulder can be used as an extra lane during busy periods.

The nearside edge (the edge up against the hard shoulder) of the running surface is marked with a solid white line, or in Ireland, a solid yellow line. The offside edge of the running surface (the edge nearest to the median) is marked with a solid white line. The running surface is divided into lanes by white dashed lines. On the M42 in the UK, the hard shoulder line is not textured because it is frequently used as a running lane.

In the UK and Ireland the lanes in a given direction are numbered sequentially from the nearside (hard shoulder) as lane 1, lane 2, lane 3, etc.

The lane closest to the hard shoulder is generally intended for normal steady driving, while the other lane or lanes, those closer to the median, are intended for overtaking or passing slower-moving vehicles. Vehicles are expected to use the nearside-most lane which is clear. The Highway Code for the UK states that vehicles must pass on the right, unless in heavy traffic or when turning left. Similar rules apply on German autobahns and in some other countries. In heavy traffic it may be acceptable to cruise in any lane and to pass slower vehicles on either side to avoid constant lane changes.

Junctions

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 at each 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. The slip roads leading off the motorway are known as 'exit sliproads', those leading onto the motorway as 'entry sliproads'. The precise sliproad at any junction may be identified by reference to the direction of the carriageway, for example 'northbound entry slip'.

The signal-controlled roundabout is often used in these situations and has become very common in Ireland. A far greater degree of complexity is present in Britain, with varying types of Spaghetti Junction-style interchanges.The M50 Western Parkway in Dublin is going through a major upgrade with spaghetti style junctions being introduced to relieve traffic congestion.

Motorway junctions are usually given a number, indicated in the UK and in Ireland with a white number on a black background in the corner of signs approaching that junction. The same junction number is used in both directions on the motorway. Sometimes, where a junction is newly inserted between two existent junctions, it will be given a letter also (e.g. 2A). In Ireland, the junction numbering has only been used consistently on the M50 since it was opened, however a junction numbering scheme is now being applied to all motorways. This has necessitated certain junctions being renumbered on the M7 (and, in future, on the M4). In Auckland, New Zealand, exit numbers are distance-based, and are indicated by a green sign reading "Exit XXX" (e.g. Exit 441) on top of exit signage.

In Ireland, when two motorways meet, it is often the end point/start point of one of the motorways. The motorway that is ending usually blends into the other at a restricted junction, permitting traffic to exit and enter the motorway from one direction only. Examples of this are the M4/M6 junction, the M7/M9 junction, and the under-construction M8/M7 junction. These junctions can cause frustration for road users, who must travel to the next available junction and then change direction to use the restricted exit.

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 bypass of built-up areas. In New Zealand, motorways tend to only occur in large cities, for purposes of taking commuters between the suburbs and the central city.

In Britain there are plans to improve many motorways as well as to upgrade some roads to motorway status. In 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 euro in such projects in the next ten years, though this could be postponed due to the economic climate.

One of the most recently constructed motorways in the UK is the M6 Toll, bypassing Birmingham and Wolverhampton, which opened in 2004 and is the only completely toll motorway in England. There are tolled sections of motorway on the M4 and M48, where they cross the River Severn at the Severn crossings. Although the crossing of the River Thames east of London on the M25 is tolled, the bridge and tunnels themselves are officially designated the A282 to permit usage by non-motorway traffic. In Ireland, the M1, M4, M8 and M50 all have tolled sections, and under construction sections of the M3, M6 and M7 also due to have tolls.

Inheritance

In the UK and in Ireland certain types of traffic are not permitted on motorways. Thus, to avoid people being forced to travel illegally, there are a number of rules about stretches of road which must be designated as motorways.

In all cases, there must be an escape route for traffic not wishing or not permitted to enter the motorway. As a result, the motorway technically begins as soon as the escape route has diverged from it; for example at a grade-separated junction, the motorway starts at the junction with the exiting slip road, and the opposite slip road is also part of the motorway for this and the following reason. An exception was the A1 near Leeds, which was "illegal", as pedestrians could legally cross 300 yards from the start, but cyclists and other types of traffic not permitted on motorways had no way of turning back - the escape route was the Boot and Shoe a mile before. This is remedied by the A1(M) extension.

As a result, this creates a less-restrictive set of rules for the standard of the road. Roads whose only destination is a motorway must be assigned motorway status, notwithstanding the possibility of their not being built to normal motorway standards. For example, the A48 motorway outside Cardiff begins after the last exit to St Mellons, since by staying on the dual carriageway you cannot get anywhere other than the M4 eastbound; however, it is a motorway-grade highway.

Route numbering

Great Britain

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. 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. 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. 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.

In Scotland, where the Scottish Office 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. The M8 follows the route of the A8, and the [[M80 motorway|M80]] became part of the M90 when the A90 was re-routed along the path of the A85.

Northern Ireland

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. 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 (similar to how motorway sections of A-roads in Great Britain are numbered).

Republic of Ireland

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). 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 which 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 only had 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 M50s designation was chosen as a recognisable number. As of 2008 the N34 is the next unused national primary road designation. In theory, a motorway in Ireland could form part of a regional road.

Elsewhere

In Hungary, similar to Ireland, motorway numbers can be derived from the original national highway numbers (1-7), with an M prefix attached, eg. 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 prefix attached, like A9 .

In New Zealand, as well as in the Scandinavian countries, and in Finland and Russia, motorway numbers are also derived from the state highway route which 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 Pakistan, motorways are denoted with the prefix M.

Motorway service areas

Environmental effects

• Roadway noise: Motorways generate more roadway noise than arterial streets because of the higher operating speeds. Therefore, noise health effects are expected from motorway systems. Noise mitigation strategies exist to reduce sound levels at nearby sensitive receptors. The idea that motorway design could be influenced by acoustical engineering considerations first arose about 1973
• Air quality issues: Motorways 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 motorways may be higher because of the substantial traffic volumes. Therefore, the risk of exposure to elevated levels of air pollutants from a motorway may be considerable, and further magnified when motorways have traffic congestion.

History

Italy

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.

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

New Zealand

New Zealand's first motorway opened in December 1950 near Wellington. This 5 kilometre (3 mile) motorway now forms part of the Johnsonville-Porirua Motorway and State Highway 1. 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.

Great Britain

A map 'Shewing Future Pattern of Principle National Routes' was issued by the Ministry of War Transport in 1946 shortly before the law that allowed roads to be restricted to specified classes of vehicle (the Special Roads Act 1949) was passed. The first section of motorway, the M6 Preston Bypass, opening in 1958 followed by the first major section of motorway (the M1 between Crick and Berrygrove) which opened in 1959. From then onwards, motorways opened on a regular basis right into the 1980s; by 1972 the first of motorway had been built. 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. The completed M25 London Orbital opened in 1986. In 1996 the total length of motorways reached .

Ireland

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

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 M1 motorway – being finished in 2005.

Under the Transport 21 infrastructural plan, motorways or high quality dual carriageways are being 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 proposed to allow existing roads be designated motorways by order. Legislation only allows for new build roads to be designated motorways. It is now intended that all the HQDCs on the major inter-urbans – other than some sections near Dublin on the N4 and N7 which do not fully meet motorway standards - will be reclassified as motorway. 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 are proposed to be reclassified as motorway.

Australia

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, 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) and Melbourne-Geelong (M1 Princes Freeway) that form part of major long-distance routes feature high-standard motorway links. While Sydney and Canberra (NH23 Federal Highway ) are the only two Australian capitals connected by a continuous motorway-standard link, 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 2000 kilometres, are underway.

Pakistan

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

Pakistan's motorways are either six-lanes or four-lanes with a universal minimum speed limit of 80 km/h and maximum speed limits of 100 km/h for heavy transport vehicles and 120 km/h for light transport vehicles. They have a central median and are fenced on the outside for safety and to prevent unauthorized access. For safety reasons, all kinds of advertising are banned on Pakistan's motorways. Entry to all motorways in Pakistan is restricted to fast moving vehicles only. Two wheelers (motorcycles and bicycles) and slow moving traffic modes are not allowed. However, the Motorway Police personnel use heavy motor bikes for patrolling purposes. Construction and agricultural machinery is also restricted.

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 and was the first motorway to be built in South Asia. The contract was awarded to the Korean firm Daewoo. The M2 is a 367 km 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 4-lane (with capacity to increase to 6 Lanes) M3 (Pindi Bhattian-Faisalabad), which links the M2 to Faisalabad and the 154 km 6-lane M1 (Peshawar-Islamabad). One additional motorway is currently under-construction, the 233 km 4-lane (with capacity to increase to 6 Lanes) M4 (Faisalabad-Multan).

Thailand

The Thai motorway network is an intercity motorway network that spans 145 kilometers. It is to be extended to over 4000 kilometers 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 kilometers 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.

See also

• Highway
• Carriageway
• Interstate highway
• List of OECD countries by road network size

List of motorways in

• Belgium
• Finland
• Hungary
• Ireland
• Morocco
• The Netherlands
• New Zealand
• Pakistan
• Poland
• The United Kingdom
• Spain

References

External links

• Department for Transport (United Kingdom)
• Highways Agency (England)
• Czech Motorways (Czech Republic)
• Slovak Motorways (Slovakia)
• Swiss Motorways (Switzerland)
• National Roads Authority (Ireland)
• eFlow - barrier free tolling operators on the M50 (Ireland)
• European Union Transport Policy
• CBRD Motorway Database
• SABRE Roads Portal
• Pathetic Motorways: Motorway Numbering Scheme
• How Motorways Work (satirical insight)
• Independent Auckland Motorways Website (New Zealand)
• Motorways in the Benelux (Benelux)
• Motorways in the Netherlands (The Netherlands)