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The 'Great Britain road numbering scheme' is a numbering system used to classify and identify all major roads in Great Britain.
Each road is given a single letter, which represents the road's category, and a subsequent number, with a length of between 1 and 4 digits. Similar systems are used in Northern Ireland (see Roads in Ireland), the Isle of Man (see Roads in the Isle of Man) and Jersey, Channel Islands. All of these numbering schemes use identical basic conventions and road-sign designs.

Contents

History of road numbering

Important radial roads in England and Wales

Important radial roads in Scotland

Zoning system

Two-digit "A" roads

Other "A" roads

Motorway sections of "A" roads

"B" roads

"C", "D" and "U" roads

Motorways

Fictional roads

Ancient roads

See also

References

External links

History of road numbering

Great Britain has many ancient roads and trackways dating back not only to the Roman occupation of southern Britain but to much earlier times, including the oldest engineered road to be discovered anywhere in the world: the Sweet Track dating from the 3800s BC.
Following the advent of the motor car around the turn of the 20th century, it was deemed necessary to invest more money in the British road system. This funding was realised through an Act of Parliament in 1919. In order to decide which roads required the most investment, the government invented a system of 'A' and 'B' numbered roads, with the former category receiving more money than the latter.
The first set of numbered roads was finalised in 1923, and was published in a book issued by His Majesty's Stationery Office. Shortly after this, the numbers started to appear in road atlases and on signs on the roads themselves, converting them into a tool for motorists in addition to their use for determining funding. The numbers of the roads changed quite frequently during the early years of the system as it was a period of heavy expansion of the network and some numbered routes did not follow the most usual routes taken.
The system, which is still used now, consists of zones defined by arterial roads nominally starting in London (although the A6 always started outside the city), numbered clockwise from the A1 to the A6, and the A7, A8 and A9 numbered clockwise from Edinburgh. Roads in between take less important, longer numbers beginning with the zone number they are in. For example, the A20 is between the A2 and the A3. Roughly speaking, the shorter the number, the more important the road, so for example the A18 is more important than the A1077.
With the introduction of motorways in the late 1950s, a new classification ''M'' was introduced. In many cases the motorways were replacing existing stretches of A-road, which therefore lost much of their significance and were in some cases renumbered. There was no consistent approach to this renumbering - some retained their existing number as non-primary A roads (e.g. the A40 running alongside the M40), others were given 'less significant' numbers (e.g. the A34 in Warwickshire became the A3400 after the M40 was built) and the remainder were downgraded to B or unclassified roads (e.g. the A38, which has been replaced by the M5 between Tiverton and Exeter). Occasionally the new motorway would take the name of the old A-road rather than having its own number. The most notable example of this is the A1(M).
In Scotland, the system has been to name motorways after the A-road they replaced by default. Northern Ireland has its own system for numbering roads.

Important radial roads in England and Wales

Important roads radiating from London have single digit numbers, starting with the A1 which heads due north. The numbering continues sequentially in a clockwise direction, thus:

★ A1 London to Edinburgh

★ A2 London to Dover (Great Dover Road)

★ A3 London to Portsmouth (Portsmouth Road)

★ A4 London to Bristol (The Great West Road, or Bath Road)

★ A5 London to Holyhead (Watling Street)

★ A6 Luton to Carlisle (The A6 originally started in Barnet on the old A1. When the A1 was moved in the late 1970s, the A6 was cut back to the A1/M25 junction. Further renumbering in the St Albans area means that it now starts in Luton town centre. The old route is numbered as A1081.)

Important radial roads in Scotland

Similarly, in Scotland, important roads radiating from Edinburgh have single digit numbers, thus:

★ A7 Edinburgh to Carlisle

★ A8 Edinburgh to Greenock

★ A9 Falkirk to Thurso (Originally Edinburgh to Inverness, it was extended to John o' Groats in the 1930s, and later cut back at the southern end because of the construction of the main runway at Edinburgh Airport on top of it. More recently, it was diverted to Thurso at the northern end.)
While the road numbering system in Scotland centres on Edinburgh, arguably the true "hub" for its road network itself is Broxden Junction in Perth.

Zoning system

In England and Wales the road numbering system for all-purpose (i.e. non-motorway) roads is based in on a radial pattern centred on London. In Scotland the same scheme is centred on Edinburgh. In both cases the main single-digit roads (largely) define the zone boundaries, with the exception of the Zones 1 and 2.
'Zone 1': North of the Thames, east of the A1

'Zone 2': South of the Thames, east of the A3

'Zone 3': North/West of the A3, south of the A4

'Zone 4': North of the A4, south/west of the A5

'Zone 5': North/East of the A5, west of the A6, south of the Solway Firth/Eden Estuary

'Zone 6': East of the A6 and A7, west of the A1

'Zone 7': North of the Solway Firth/Eden Estuary, west of the A7, south of the A8

'Zone 8': North of the A8, west of the A9

'Zone 9': North of the A8, east of the A9

Motorways in England and Wales use a similar zoning system, based on the single-digit motorways. Motorways in Scotland are numbered differently.
The first digit in the number of any road should be the number of the furthest-anticlockwise zone entered by that road. For example, the A38 road, a trunk road running from Bodmin to Mansfield starts in Zone 3, and is therefore numbered with a A3x number, even though it passes through Zones 4 and 5 to end in Zone 6. Additionally, the A1 in Newcastle upon Tyne has moved twice. Originally along the Great North Road, it then moved to the Tyne Tunnel, causing some of the roads in Zone 1 to now be in Zone 6, and some were renumbered. It was later moved to the western bypass around the city, and roads between the two found themselves back in Zone 1, and were renumbered wholesale. This did not always happen, however, and when single-digit roads were bypassed, roads were often re-numbered in keeping with the original zone boundaries.
To view a list of roads where this does not apply, see Anomalously numbered roads in Great Britain.

Two-digit "A" roads

These radials are supplemented by two-digit codes which are routes that are slightly less important (but may still be classified as trunk routes), although many of these routes have lost a lot of their significance due to motorway bypasses, or the upgrading of other A-roads. These routes are not all centred on London, but as far as possible follow the general principle that their number locates them radially clockwise from the associated single digit route. For example, the A10 (London to King's Lynn) is the first main route clockwise from the A1, the A11 is the next, and so on:

★ A10 London to King's Lynn (known as the Great Cambridge Road or the Old North Road)

★ A11 London to Norwich

★ A12 London to Great Yarmouth

★ A13 London to Shoeburyness

★ A14 M1/M6 Catthorpe junction near Rugby to Felixstowe (Originally Royston to Huntingdon)

★ A15 Peterborough to Hull

★ A16 Stamford to Grimsby

★ A17 Newark to King's Lynn

★ A18 Doncaster to Ludborough

★ A19 Doncaster to Seaton Burn

★ A20 London to Dover

★ A21 London to Hastings

★ A22 London to Eastbourne

★ A23 London to Brighton

★ A24 London to Worthing

★ A25 Wrotham Heath to Guildford

★ A26 Maidstone to Newhaven

★ A27 Pevensey to Whiteparish

★ A28 Margate to Hastings

★ A29 Beare Green to Bognor Regis

★ A30 London to Land's End

★ A31 Guildford to Bere Regis

★ A32 Alton to Gosport

★ A33 Southampton to Reading

★ A34 Winchester to Salford

★ A35 Southampton to Honiton

★ A36 Southampton to Bath

★ A37 Dorchester to Bristol

★ A38 Bodmin to Mansfield

★ A39 Bath to Falmouth

★ A40 London to Fishguard

★ A41 London to Birkenhead

★ A42 Appleby Magna (M42) to Kegworth(M1) (Originally Reading to Birmingham: taken over by A34)

★ A43 Cherwell Valley to Stamford (formerly Oxford to Market Deeping)

★ A44 Oxford to Aberystwyth

★ A45 Birmingham to Thrapston (Originally to Felixstowe, but eastern section taken over by A14)

★ A46 Bath to Cleethorpes

★ A47 Birmingham to Great Yarmouth

★ A48 Highnam to Carmarthen

★ A49 Ross-on-Wye to Bamber Bridge near Preston

★ A50 Leicester to M1 Junction 22 and Kegworth (M1 Junction 24) to Warrington (formerly Northampton to Warrington)

★ A51 Kingsbury to Chester

★ A52 Newcastle-under-Lyme to Mablethorpe

★ A53 Shrewsbury to Buxton

★ A54 Chester to Buxton

★ A55 Holyhead to Chester (The North Wales Expressway)

★ A56 Chester to Broughton (A59)

★ A57 Liverpool to Lincoln

★ A58 Prescot to Wetherby

★ A59 Liverpool to York

★ A60 Loughborough to Doncaster

★ A61 Derby to Thirsk

★ A62 Manchester to Leeds

★ A63 Leeds to Hull

★ A64 Leeds to Scarborough

★ A65 Leeds to Kendal

★ A66 Workington to Grangetown

★ A67 Bowes (A66) to Crathorne (A19)

★ A68 Darlington to Edinburgh

★ A69 Carlisle to Blaydon

★ A70 Edinburgh to Ayr

★ A71 Edinburgh to Irvine

★ A72 Galashiels to Hamilton

★ A73 Abington to Cumbernauld

★ A74 Carlisle to Glasgow

★ A75 Gretna to Stranraer

★ A76 Dumfries to Kilmarnock

★ A77 Glasgow to Portpatrick

★ A78 Prestwick to Greenock

★ A79 Prestwick to Doonholm

★ A80 Glasgow to Bonnybridge

★ A81 Glasgow to Callander

★ A82 Glasgow to Inverness

★ A83 Campbeltown to Tarbet

★ A84 Stirling to Lochearnhead

★ A85 Oban to Dundee

★ A86 Spean Bridge to Kingussie

★ A87 Invergarry to Uig

★ A88 Larbert to Stenhousemuir (Originally what is now the A9 past Inverness: this explains the rarity of A9xxx numbers in the Highlands)

★ A89 Newbridge to Glasgow

★ A90 Edinburgh to Fraserburgh

★ A91 Bannockburn to St Andrews

★ A92 Dunfermline to Stonehaven

★ A93 Perth to Aberdeen

★ A94 Perth to Forfar

★ A95 Aviemore to Meld

★ A96 Inverness to Aberdeen

★ A97 Dinnet to Banff

★ A98 Fochabers to Fraserburgh

★ A99 Latheron to John o' Groats
Note on numbering: These roads have been numbered either outwards from or clockwise around their respective hubs, depending on their alignment.

Other "A" roads

The system continues to three and four digit numbers which further split and criss-cross the radials. Lower numbers originate closer to London than higher numbered ones. Most roads built or reclassified since road numbers were introduced in 1919 have four-digit numbers. Knowing the number of the road you are on will give you a rough idea of where you are geographically once the system is understood. Below is a rough guide to the numbering series which apply to the various areas of the Great British mainland:

★ 10 and 100 series numbers: Greater London, Essex, Cambridgeshire, East Anglia, Lincolnshire, parts of Yorkshire, Cleveland, Tyne and Wear, Northumbria, and on up to Edinburgh.

★ 20 and 200-series numbers: Surrey, Sussex and Kent

★ 30 and 300-series numbers: Hampshire, the Isle of Wight, Dorset and South West England

★ 40 and 400-series numbers: Central England and south and Mid Wales

★ 50 and 500-series numbers: North Wales, North Midlands, Cheshire, Cumbria and Lancashire

★ 60 and 600-series numbers: North-East England, Yorkshire and South East Scotland

★ 70 and 700-series numbers: South West and Central Scotland

★ 80 and 800-series numbers: North West Scotland and the Western Isles

★ 90 and 900-series numbers: North East Scotland, Orkney and Shetland
Some of the most important 3-digit "A" roads are:

★ A127 Romford to Southend-on-Sea (the Southend Arterial Road or New Southend Road)

★ A205 Woolwich to Chiswick (South Circular Road)

★ A259 Folkestone to Havant. Forms part of the South Coast Trunk Road between the A2070 and A27.

★ A272 Poundford to A30 near Andover

★ A303 Basingstoke to Honiton (relieves traffic from the A30)

★ A361 Ilfracombe to Rugby (the longest 3-digit road)

★ A403 Avonmouth to Aust

★ A406 Chiswick to Beckton (North Circular Road)

★ A414 Hemel Hempstead to Maldon

★ A465 Bromyard to Neath (Head of the Valleys Road)

★ A470 Cardiff to Llandudno

★ A483 Swansea to Chester

★ A487 Haverfordwest to Bangor

★ A580 Liverpool to Manchester (East Lancs Road)

★ A538 Altrincham to Wilmslow (Hale Road becoming Wilmslow Road)

★ A689 Carlisle to Hartlepool

★ A720 Edinburgh City Bypass
A small number of 4-digit A roads have grown in importance since the numbers were allocated:

★ A1079 Hull to York

★ A2070 Ashford to Romney Marsh in Kent. Now part of the South Coast Trunk Road.

Motorway sections of "A" roads

Some sections of "A" roads have been improved to the same standard as motorways, but do not completely replace the existing road; they form a higher standard part of the A-road route. These sections retain the "A" road designation, but are suffixed '(M)'. Examples include:

★ A1(M)

★ A404(M)
There have been occasions where this designation has been used to indicate motorway bypasses of an existing road, but the original retains the A road designation. Examples include:

★ A3(M)

★ A308(M)

★ A329(M)

★ A48(M)

"B" roads

'"B" roads' are numbered local routes, which have lower traffic densities than the main trunk roads, or A road. They are typically short, not usually more than 15 miles. The classification has nothing to do with the width or quality of the physical road, and B roads can range from dual carriageways to single track roads with passing places. B roads follow the same numbering scheme as A roads, but almost always have 3- and 4-digit designations. Many 3-digit B roads outside the London area are former A roads which have been downgraded owing to new road construction; others may link smaller settlements to A roads.

"C", "D" and "U" roads

Roads and lanes with yet lower traffic densities are designated "C", "D" and "U" (Unclassified) roads, but while these are numbered, in general this is done purely for the benefit of the local authorities who are responsible for maintaining them, and the numbering is arbitrary and does not, or should not, appear on any public signage. Some exceptions to this are known, however. [1] These other classified roads, however, are taken into account when planning officers deal with certain planning applications.

Motorways

:''Main article: List of motorways in the United Kingdom
The first motorway in Britain was the Preston Bypass, opened in December 1958. This is now a section of M6, plus the M55 to junction 1. The M1, M10 and M45 opened together in 1959.
Motorways first came to Britain over three decades after the advent of the A-road numbering event, and as a result required a new numbering system. They were given an M prefix, and (in England and Wales) a numbering system of their own not conterminous with that of the A-road network, though based on the same principle of zones.
The most important single-digit motorways were numbered to (loosely) match the existing main roads which the motorway follows or was intended to relieve traffic from. The level of correlation differs; the M4 motorway stays very true to the line of the A4 road throughout England, whereas the M1 motorway meanders a path not too close to the A1 road, although generally north-south like its predecessor.
A very obvious exception to this rule is the M5, which closely follows the A38. It was numbered uniquely as it was already known that the A5 road needed no such motorway bypass as this was already the job of the M1/M6.^[1]
The single-digit motorways mark out zones or cones, the concept analogous with that of the A-road network. However, due to the difference in position of the A5 vs. the M5, the actual position of these zones varies greatly, especially in the Midlands and South West England.
Shorter motorways typically take their numbers from a parent motorway in violation of the zone system, explaining the apparently anomalous numbers of the M48 and M49 motorways as spurs of the M4, and M271 and M275 motorways as those of the M27. The latter two might be explained by the original plan for the M3 motorway, which was due to head towards Exeter, rather than Southampton as it does now. The original committee which set up the motorway zones chose the boundary of zones 2 and 3 to be the projected line of the M3 towards Exeter, although it's not currently known whether this is still the case.
This numbering system was devised in 1958-9 by the then Ministry of Transport and Civil Aviation, and applied only in England and Wales. In Scotland, where roads were the responsibility of the Scottish Office, the decision was taken to adopt the numbering originally proposed, in that motorways took the numbers of the all-purpose routes they replaced. As a result, there is no M7 (as no motorway follows the A7), and when the A90 was re-routed to replace the A85 south of Perth, the short M85 became part of the M90.

Fictional roads

Fictional numbers are assigned for use on TV and film; such a number that is involved with a serious fictional accident is blacklisted for five years from actual use.^[2]

Ancient roads

Some ancient routes, such as Roman roads, travel for great distances and have a single modern number for the majority of their length (e.g. the A5 for the Roman road Watling Street). Others, such as the pre-Roman Icknield Way and the Roman Fosse Way are nowadays rather patchy and where a modern road exists, are numbered according to the local scheme. Much of the A1 follows Dere Street.

See also

★ UK topics

References

1. Pathetic Motorways - Motorway Numbering Scheme Part 2
2. http://www.southerncarclub.com/may99-5.htm

External links

★ SABRE > Roaders' Digest

★ The First 99 - information on one- and two-digit A roads

★ Roads By 10 - information on three-digit A roads

★ British Roads FAQ