A12 road

From Academic Kids

The A12 is a major road in England, a trunk road for most of its length, running from London to Great Yarmouth in Norfolk.

Starting at the Blackwall Tunnel, it heads north, then north east through Leyton, Leytonstone, Gants Hill and Romford, then into Essex, passing Brentwood, Chelmsford and Colchester. In Suffolk, it passes Ipswich, Woodbridge and Saxmundham, then follows the coast through Lowestoft and Gorleston before entering Norfolk and ending at Great Yarmouth.



The section from the Blackwall Tunnel to Leytonstone, which is all dual carriageway, was built in the 1990s. This section has an underpass at the Bow Interchange roundabout, a junction with the A11. The old section as far as Wanstead was rebuilt as a dual carriageway. Prior to that, the A12 started at the Green Man Roundabout at Leytonstone, and was single carriageway west of Wanstead tube station. It now has an underpass at that roundabout, which again is a junction with the A11.

East of Wanstead, the A12 runs roughly due east. It is known as Eastern Avenue, then Eastern Avenue West and Eastern Avenue East until it reaches Gallows Corner in the London Borough of Havering, just east of Romford. (This is where the A127 starts.) It now veers roughly north-eastward, because it starts to follow the course of the Roman road from Colchester to London. (The Romans started building this road from Colchester, their original capital for the province.) Originally, the A12 followed the Roman road fairly closely hence was fairly straight, but there are now several town bypasses, so the road through Essex looks quite wavy on a map. However, the 2.5 mile (4 km) stretch from Gallows Corner to the junction with the M25 motorway, called Colchester Road, is still perfectly straight. The M25 junction is number 28; it also marks where the A12 crosses the boundary from London to Essex.


The A12 formerly went through Brentwood, Mountnessing, Ingatestone, Margaretting, Chelmsford, Boreham, Hatfield Peverel, Witham, Kelvedon, Copford, Stanway and Colchester, but these are all now bypassed, and the A12 is close to motorway standard for its whole length in Essex.


Built in the 1970s, the A12 Colchester bypass provides an uninterrupted dual carriageway where the national speed limit (70 mph or 113 km/h) applies.

Prior to the 1970s, the A12 took a route much closer to Colchester itself, and although still a bypass it consisted of urban single carriageways with roundabouts and pedestrian crossings. The old bypass is still in existence; the western half is now part of the A604 and the eastern half part of the A133.


For most of its length through Suffolk the A12 is a single carriageway road and in many places its speed limit is less the national limit, for example as it passes through towns and villages. During 2003/2004 some of these speed restrictions were further reduced from 40mph to 30mph.


In order to bypass Ipswich along its southern edge, the A12 is discontinuous and uses a 7 mile (11 km) section of the A14 accessed at roundabout junctions, where A14 traffic has unrestricted through flow and A12 traffic has to use the roundabouts.


The A12 runs through Lowestoft for about 5 miles (8 km) on urban 30 mph (48 km/h) limited roads. A further impediment is the harbour bridge, which has three lanes, the centre lane operating as a one-way addition to whichever direction of flow is deemed greater according to time of day.

An alternate route avoiding Lowestoft is available through Oulton Broad (the town of), but again via urban roads and a bridge.

The presence of these bridge choke points can cause serious disruption to north-south trunk traffic, especially when local traffic is added during rush hours.

A proper bypass for Lowestoft would have to be well to the west, even to the west of Oulton Broad (the body of water), and its route would have to consider the great extent of marshland in that area. For that reason an often discussed compromise is a third bridge, crossing Lake Lothing, linking the sections of urban spine-road that run approximately along the western edge of Lowestoft.



From a point just south west of the mouth of the River Yare, northwards to the point where it actually crosses the River Yare in Great Yarmouth, the A12 now follows the route originally used by the railway line from Lowestoft to its terminus at Great Yarmouth's Southtown Station.


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