| Almondsbury Interchange | |
|---|---|
 Interactive map of Almondsbury Interchange | |
| Location | |
| Almondsbury,South Gloucestershire | |
| Coordinates | 51°33′05″N2°33′09″W / 51.551432°N 2.552444°W /51.551432; -2.552444 |
| Roads at junction | |
| Construction | |
| Type | Stack interchange |
| Constructed | 1964 byRichard Costain Ltd |
| Opened | 8 September 1966 (1966-09-08) |
| Maintained by | National Highways |
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TheAlmondsbury Interchange inSouth Gloucestershire, is one of theUnited Kingdom's largest motorwaystack interchanges. The interchange is one of only three four-level stacks in the UK, and including slip roads covers 1 square kilometre (0.39 sq mi). It is the interchange for theM5 at junction 15 andM4 at junction 20, and is situated at the northern fringes ofBristol close to the village ofAlmondsbury, theAztec West industrial estate, andBradley Stoke. When it opened in 1966, it was the most complex junction on the British motorway network, a free-flowing interchange on four levels. Since then traffic volumes have increased. At busy periods, the interchange becomes more difficult to negotiate safely. In an attempt to ease congestion, the Interchange has become part of asmart motorway.
The Almondsbury Interchange is immediately adjacent to junction 16 of the M5, which allows traffic on and off the motorway from theA38 road running betweenBristol andGloucester. The slip roads from the A38 junction intertwine with those from the M5/M4 interchange. Unusually within the UK motorway system, this forces multiple lane changes for vehicles traversing some of the routes. The centres of the junctions are atOrdnance Survey Grid References ST 617837 (M5 J15/ Almondsbury Interchange) and ST 606833 (M5 J16/ A38), and are therefore 1.2 kilometres (0.75 mi) apart.[1]
Almondsbury Interchange was the first four-level interchange in the United Kingdom.[2] It was designed byFreeman Fox and Robert Earley.[3] When it opened in 1966, it was the most complex junction on the British motorway network.[4]The interchange was built byRichard Costain Ltd, with work commencing in May 1964. The bridge was opened by theQueen on 8 September 1966.[5]
The interchange handles high volumes of traffic especially in the morning and evening rush hours.[6][4] It is overlooked by theRAC Tower. Traffic travelling between the M5 andSecond Severn Crossing can bypass the interchange by using theM49 motorway.[1]
Under normal conditions, traffic flows freely through the interchange. Congestion becomes a problem in heavy traffic flow, such as during the summer holiday season, because of the close proximity of the A38 junction. This makes the required changing of lanes when travelling west on the M5 much more problematic.[4]
The interchange is at the centre of amanaged motorway project which covers junctions 19 to 20 on the M4 and 15 to 17 on the M5. This became fully operational in January 2014, after being installed over a two-year period. It involves the use of the hard shoulders on the M4 and M5 over seven miles of motorway during busy times, at which time a variable speed limit function is activated. Thirty-three new overhead gantries have been installed to advise motorists on the speed limits applicable at the time. The system is being enforced by speed cameras, and there are six emergency refuge areas for motorists who get into difficulties.[7]
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