A roundabout, a rotary and a traffic circle are all, with certain distinctions between them, a type of circular intersection or junction in which road traffic is permitted to flow in one direction around a central island, and priority is typically given to traffic already in the junction.
The M4, originally the London-South Wales Motorway, is a motorway in the United Kingdom running from west London to southwest Wales. The English section to the Severn Bridge was constructed between 1961 and 1971; the Welsh element was largely complete by 1980, though a non-motorway section around Briton Ferry bridge remained until 1993. On the opening of the Second Severn Crossing in 1996, the M4 was rerouted over it.
The A4 is a major road in England from Central London to Avonmouth via Heathrow Airport, Reading, Bath and Bristol. It is historically known as the Bath Road with newer sections including the Great West Road and Portway. The road was once the main route from London to Bath, Bristol and the west of England and formed, after the A40, the second main western artery from London.
The A12 is a major road in Eastern England. It runs north-east/south-west between London and the coastal town of Lowestoft in the north-eastern corner of Suffolk, following a similar route to the Great Eastern Main Line until Ipswich. A section of the road between Lowestoft and Great Yarmouth became part of the A47 in 2017. Between the junctions with the M25 and the A14, the A12 forms part of the unsigned Euroroute E30. Unlike most A roads, this section of the A12, together with the A14 and the A55, has junction numbers as if it were a motorway.
The A48 is a trunk road in Great Britain running from the A40 at Highnam, 3 miles (4.8 km) west of Gloucester, England, to the A40 at Carmarthen, Wales. Before the Severn Bridge opened on 8 September 1966, it was a major route between England and South Wales. For most of its route, it runs almost parallel to the M4 motorway. During times of high winds at the Severn Bridge, the A48 is used as part of the diversion route and is still marked as a Holiday Route.
The Magic Roundabout in Swindon, England, is a ring junction constructed in 1972 consisting of five mini-roundabouts arranged in a circle. Located near the County Ground, home of Swindon Town F.C., its name comes from the popular children's television series The Magic Roundabout. In 2009, it was voted the fourth-scariest junction in Britain.
"The Magic Roundabout" in Hemel Hempstead, Hertfordshire, England, is the familiar name given to the Plough Roundabout. The familiar name comes from the children's television programme, and is also used for a similar junction in Swindon, the M40 junction in Denham, and the Magic Roundabout in Colchester. The official name relates to a former public house, called The Plough Inn, which was between the junction of what is now Selden Hill and St Albans Road. It has also been known as the Moor End Roundabout as it is adjacent to the part of Boxmoor nearest the town. Before Hemel Hempstead became a new town the roads met in a simple junction which was then replaced by a standard roundabout.
The A419 road is a primary route between Chiseldon near Swindon at junction 15 of the M4 with the A346 road, and Whitminster in Gloucestershire, England near the M5 motorway. The A419 is managed and maintained by a private company, Road Management Group, on behalf of the UK Department for Transport.
The A417 is a main road in England running from Streatley, Berkshire to Hope under Dinmore, Herefordshire. It is best known for its section between Cirencester and Gloucester where it has primary status and forms part of the link between the major settlements of Swindon and Gloucester.
The Denham Roundabout is a road junction in Denham, Buckinghamshire. It was originally opened in 1943 in conjunction with the completion of the new Western Avenue route into west London. The Western Avenue took over the classification of the A40, with the previous route to London, via Uxbridge and Ealing, being reclassified as the A4020. The roundabout also included a new link to A412 that formed part of the outer London orbital route.
In the field of road transport, an interchange or a grade-separated junction is a road junction that uses grade separations to allow for the movement of traffic between two or more roadways or highways, using a system of interconnecting roadways to permit traffic on at least one of the routes to pass through the junction without interruption from crossing traffic streams. It differs from a standard intersection, where roads cross at grade. Interchanges are almost always used when at least one road is a controlled-access highway or a limited-access divided highway (expressway), though they are sometimes used at junctions between surface streets.
The A420 is a road between Bristol and Oxford in England. Between Swindon and Oxford it is a primary route.
The A120 is an A-road in England, which runs between Puckeridge in Hertfordshire and Harwich in Essex.
The A556 is a road in England which extends from the village of Delamere in Cheshire West and Chester to the Bowdon Interchange in Cheshire East, bordering Greater Manchester. The road contains a mixture of single and dual carriageway sections and forms a large part of the route between Manchester and Chester. It also acts as a major access route to Chester/North Wales to the west and to Manchester to the east for the conurbation of towns and villages around the Dane Valley centering on Winsford and Northwich. The central part, which forms the Northwich Bypass between Davenham and Lostock Gralam, suffers because of the amount of commuter traffic from this area. The part of the route between the M6 motorway Junction 19 and the M56 motorway Junction 7 is a major route into Manchester and has been recently upgraded to a four-lane dual carriageway.
The A130 is a major road in England linking Howe Green, near Chelmsford, the county town of Essex, with Canvey Island in the south of that county. It is a primary route for some of its length, only losing that status south of the A13 junction at Sadlers Farm roundabout as it nears its terminus on Canvey Island. It was originally a much longer cross-country route.
The A4008 is a local road in south east England.
The A345 is a secondary A road in Wiltshire, England running from Salisbury to Marlborough and the A4. The road is a main south–north link across Salisbury Plain, which is renowned for its rich archaeology, and passes many ancient points of interest along its way.
A roundabout interchange is a type of interchange between a controlled access highway, such as a motorway or freeway, and a minor road. The slip roads to and from the motorway carriageways converge at a single roundabout, which is grade-separated from the motorway lanes with bridges.
The A4160 is a road between Cardiff and Penarth in Wales. Its role as the main road between Cardiff city centre and Penarth has largely been superseded by the A4055 and A4232 roads via Cardiff Bay.
The Magic Roundabout in High Wycombe, Buckinghamshire, England, is similar to the complex roundabouts in Hemel Hempstead and other places. It is located on the junction of the A40 and A404 roads.
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