British road numbering scheme
Britain has a long history, and has many ancient roads and trackways dating back to the Roman occupation and before. With the advent of the car and the huge expansion in the numbers and standards of roads, as well as the introduction of a national Highway Code, a coherent numbering scheme was developed, which is still in use today.The road numbering system in England and Wales is based on a radial pattern centered on London. Scotland has an extension of the scheme based on Edinburgh.
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2 Main trunk routes in Scotland 3 Two-digit "A" roads 4 Other "A" roads 5 "B" roads 6 Motorways 7 Ancient roads 8 See Also |
Main trunk routes in England and Wales
Main trunk routes 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 (The Great North Road)
- A2 London to Dover (Watling Street)
- 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
Main trunk routes in Scotland
Similarly, in Scotland, main trunk routes radiating from Edinburgh have single digit numbers, thus:
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). 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 Cambridge) is the first main route clockwise from the A1, the A11 (London to Norwich) is the next, and so forth. Some of the more important ones are:
- A10 London to Cambridge
- A11 London to Norwich
- A12 London to Colchester
- A13 London to Shoeburyness
- A14 Felixstowe to Rugby
- A15 Hull to Peterborough
- A16 Stamford to Grimsby
- A17 King's Lynn to Newark-on-Trent
- A18 Doncaster to Ludborough
- A19 Doncaster to Seaton Burn
- A20 London to Folkestone
- 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 Whiteparish to Pevensey
- 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 Reading to Southampton
- A34 Salford to Winchester
- A35 Honiton to Southampton
- A36 Bath to Southampton
- A37 Bristol to Dorchester
- A38 Bodmin to Mansfield
- A39 Bath to Falmouth
- A40 London to Fishguard
- A41 London to Birkenhead
- A42 Appleby Magna (M42) to Kegworth (M1)
- A43 Cherwell Valley to Stamford
- A44 Oxford to Aberystwyth
- A45 Birmingham to Thrapston
- A46 Newark to Bath
- A47 Great Yarmouth to Birmingham
- A48 Highnam to Camarthen
- A49 Ross-on-Wye to Bamber Bridge
- A50 Leicester to Warrington
- A51 Chester to Kingsbury, Warwickshire
- A52 Newcastle-under-Lyme to Mablethorpe
- A53 Buxton to Shrewsbury
- A54 Buxton to Tarvin (Chester)
- A55 Chester to Holyhead (The North Wales Expressway)
- A56 Chester to Broughton (A59)
- A57 Liverpool to Lincoln
- A58 Prescot to Wetherby
- A59 Liverpool to York
- A61 Alfreton to Thirsk
- A62 Manchester to Leeds
- A66 Middlesbrough to Workington
- A68 Darlington to Edinburgh
- A77 Glasgow to Portpatrick
- A82 Glasgow to Inverness
- A90 Edinburgh to Fraserburgh
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. 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. Some of the most important are:
- A205 Woolwich to Kew (South Circular Road)
- A303 Basingstoke to Honiton
- A406 Kew to North Woolwich (North Circular Road)
- A470 Cardiff to Llandudno
- A483 Swansea to Chester
"B" roads
"B" roads are routes which have lower traffic densities than "A" roads. The classification has nothing to do with the width or quality of the physical road. B roads follow the same numbering scheme as A roads, but almost always have 3- and 4- digit designations. Most 3-digit B-roads are former A-roads which have been downgraded due to new road construction.Roads and lanes with yet lower traffic densities are designated 'C' roads, but while these are numbered, in general this is done purely for the benefit of the local authorities, etc. who are responsible for maintaining them, and the numbering is arbitrary and does not appear on any public signage.
Motorways
Motorways came to Britain much later than the established routes and the numbering system was already in place.Therefore the motorways are designated "M" roads and are numbered to match the existing main radials which the motorways in general follow. One exception is the M5 whose closest A-road equivalent is the A38. The numbering of two digit motorways is based on a zone system formed by the 1-digit motorways, not on the zone system formed by the 1-digit A-roads. The other exception is the M6 Toll a recently opened toll motorway which bypasses the busiest section of the M6 around Wolverhampton and Birmingham.
