Single-digit A roads In England and Wales, the six single-digit numbers reflect the traditionally most important radial routes coming out of
London, Starting with the
A1 which heads due north, numbers were allocated sequentially in a clockwise direction, thus: •
A1 London to
Edinburgh (also known as the Great North Road). The southern half of the road is bypassed by the
M1 and many sections have been upgraded to
A1(M). •
A2 London to
Dover (the southern part of Watling Street, also known as the Dover Road). •
A3 London to
Portsmouth (also known as the Portsmouth Road). •
A4 London to
Avonmouth (also known as the Great West Road or the Bath Road), although this route is not used as a long-distance road since the completion of the
M4. •
A5 London to
Holyhead (the Northern part of Watling Street). Much of the southern part is bypassed by the
M1 and
M6. •
A6 Luton to
Carlisle (The A6 originally started in Barnet on the old A1. When the A1 was moved onto the Barnet Bypass in the 1950s, the A6 was cut back to the A1/A1(M) junction (later 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). The northern part is paralleled by the
M6. Similarly, in Scotland, important roads radiating from Edinburgh have single-digit numbers, thus: •
A7 Edinburgh to
Carlisle, although the
M74 and
M8 motorways now form the primary link. •
A8 Edinburgh to
Greenock, which formerly linked Edinburgh to
Glasgow, now has a gap, where it is replaced by the
M8. •
A9 Falkirk to
Scrabster. Originally Edinburgh to
Inverness, the A9 was extended to
John o' Groats via
Wick on 16 May 1935, and later cut back at the southern end because of the construction of the main runway at
Edinburgh Airport on top of it. As such, the route from Edinburgh is now replaced by the
M9 (with the
M90 across the
Queensferry Crossing as an alternative to
Perth). On 1 April 1997, the A9 was diverted to
Thurso and Scrabster at the northern end. While these routes remain the basis for the numbering of the A road network, they are no longer necessarily major roads, having been bypassed by motorways or other changes to the road network.
Other A roads These radials are supplemented by two-digit codes which are routes that
may be 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 (such as the
A38 (M)). 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 (London to Norwich) is the next, then the
A12 (London to Lowestoft) and the
A13 (London to Shoeburyness); the next radial is the
A2, followed by the
A20 (London to Dover), and so on. These roads have been numbered either outwards from or clockwise around their respective hubs, depending on their alignment. 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. As roads have been improved since the scheme commenced, some roads with 3 or 4 digit numbers have increased in significance, for example the
A127,
A1079 and
A414. New routes have also been allocated 3 or 4 digit numbers, for example the Edinburgh City Bypass is the
A720. The
Major Road Network is a proposed classification of major local-authority controlled A roads that the government committed to implementing in 2017, with the aim of better targeting road funding.
Lists of A roads •
Zone 1 A roads •
Zone 2 A roads •
Zone 3 A roads •
Zone 4 A roads •
Zone 5 A roads •
Zone 6 A roads •
Zone 7 A roads •
Zone 8 A roads •
Zone 9 A roads Trunk roads and primary routes Some A roads are designated
trunk roads, which implies that central government rather than local government has responsibility for them. A more recent classification is that of
primary routes, the category of recommended routes for long-distance traffic. Primary routes include both trunk and non-trunk roads.
Motorway sections 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 route for those which are not excluded. These sections retain the same number but are suffixed with (M), for example the
A1(M) and
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, for example
A3(M),
A329(M),
A38(M),
A48(M) and
A627(M). == B roads ==