Learn more about A406 road
In the west, it starts at junction 1 of the M4 motorway at Gunnersbury, where it also meets the South Circular Road. The road runs north as Gunnersbury Avenue, crossing Uxbridge Road (A4020) at Ealing Common. As Hanger Hill, the A406 continues north to the Hanger Lane Gyratory System where it crosses Western Avenue (A40) and turns north-east. Now under the name North Circular Road, the A406 continues past Stonebridge Park station, and passes under Harrow Road (A404) before continuing through Neasden past Welsh Harp Reservoir. After an interchange with Edgware Road (A5) it meets junction 1 of the M1 motorway at Staples Corner.
It then passes the Brent Cross Shopping Centre and Brent Cross Interchange (A41), and travels between Golders Green and Hendon. It shares carriageways with the A1 for a short distance at Finchley, forming the boundary between Finchley Central and East Finchley. It then passes north of St Pancras and Islington Cemetery where at Friern Barnet it becomes Pinkham Way with a short single lane section. Subsequently turning right into Bowes Road it becomes the North Circular Road again at Green Lanes. At its most northern point, the A406 interchanges with Great Cambridge Road (A10) and becomes Sterling Way. After it crosses Fore Street it becomes Angel Road which leads into the Lea Valley Viaduct as it crosses the River Lea.
It becomes Southend Road and passes north of Walthamstow, having a junction at the Crooked Billet and then crosses the Woodford New Road at the Waterworks Corner, a section of road completed in the early 1990s.
East from the Waterworks, the Southend Road enters a cutting, completed in the 1970s, and travels under the old A11 at Gates Corner (previously there were traffic lights at a crossroads here). The North Circular leaves the Southend Road at an elevated junction with the M11 motorway above Charlie Brown's Roundabout, it turns south, passing Eastern Avenue (A12) on a flyover at Redbridge Interchange. It passes Romford Road to the west of Ilford, then crosses Barking Road in Barking, and ends at an interchange with the A13 Newham Way in Beckton. The road then links, via the free Woolwich Ferry across the River Thames, with the eastern end of the South Circular Road on the other side of the river. The junction with the A13 has been built to enable the North Circular to be continued across the junction to the Thames Gateway Bridge when it is built.
The section east of Waterworks Corner is relatively recent. Before it was built, the North Circular Road went to Gants Hill. This old stretch (Southend Road and Woodford Avenue) has been re-numbered the A1400.
 Ringway 2
In the late 1960s the Greater London Council developed the London Ringways Plan to construct a series of circular and radial motorways throughout London to ease traffic congestion in the central area. Under this plan the North Circular Road was designated as the northern section of Ringway 2 and was scheduled to be upgraded to a motorway designated as the M15. Most of the Ringway Plans were cancelled in the early 1970s and the North Circular Road was never upgraded to full motorway standard, although much of it is now grade separated dual carriageway.
The section of the North Circular south of M11 junction 4 (the "South Woodford to Barking Relief Road") was constructed on the alignment planned for the unrealised motorway plans and the section between the M11 and A12 junctions was originally opened as part of the M11 with the interchange at Redbridge designated as M11 junction 3. The intention was to rename this section as M15 once the A406 upgrade to motorway standard had proceeded further but this never happened and the road was eventually downgraded from motorway to A road keeping the existing A406 designation.
Although the route has alternate names at some points, it is generally referred to as the North Circular throughout for route planning purposes. The route is mostly grade separated dual carriageway from the A40 to the A13 except for the Drury Way/Brentfield Road junction, the Golders Green Road/Brent Street junction, Henlys Corner and Bounds Green - Green Lanes.
In 2004, Mayor of London Ken Livingstone promised limited improvements to the road, but he has received criticism for not approving earlier plans for widening the often heavily congested road at critical sections.
London's successful bid to host the 2012 Summer Olympics has increased speculation that the road will be upgraded to provide for adequate traffic during the Games.
 External links
|Image:UK road A4.PNG||A roads in Zone 4 of|
the Great Britain road numbering system
|A4||A40 - A41 - A42 - A43 - A44 - A45 - A46 - A47 - A48 - A49|
|A403 - A406 - A413 - A414 - A417 - A418 - A419|
|A420 - A421 - A422 - A425 - A426 - A427 - A428 - A429 - A435 - A441 - A442 - A445 - A449|
|A452 - A453 - A454 - A456 - A458 - A465 - A470 - A472 - A478 - A482 - A483 - A487 - A488|
|A494 - A497 - A498 - A499|
|A4006 - A4012 - A4018 - A4025 - A4040 - A4042|
|A4103 - A4117 - A4150 - A4133 - A4142 - A4146 - A4174|
|A4202 - A4212 - A4400 - A4536 - A4540|
|List of A roads in Zone 4|