A junction is where two or more roads meet.
24-726: Spaghetti Junction , officially the Gravelly Hill Interchange , is a major road junction in Birmingham , England. It is junction 6 of the M6 motorway where it meets the A38(M) Aston Expressway in the Gravelly Hill area of Birmingham. The interchange was opened on 24 May 1972. The asymmetrical junction provides access to and from the A38 (Tyburn Road), A38(M) ( Aston Expressway ),
48-558: A new settlement. Scotch Corner is an example of such a location. In the United Kingdom and other countries, the practice of giving names to junctions emerged, to help travellers find their way. Junctions took the name of a prominent nearby business or a point of interest. As of the road networks increased in density and traffic flows followed suit, managing the flow of traffic across the junction became of increasing importance, to minimize delays and improve safety. The first innovation
72-473: A number of objections and protests over the interchange, particularly a campaign to "save our fish" to relocate a quarter of a million fish from a pool that would be removed as part of the engineering work. One stipulation in construction was that the canal towpaths running underneath the junction need to retain sufficient clearance to allow the passage of horse-drawn narrowboats . Work was mostly complete by May 1970, and attracted attention of local residents. By
96-414: A plate of spaghetti and an unsuccessful attempt at a Staffordshire knot " and sub-editor Alan Eaglesfield headlined the article "Spaghetti Junction". The name would later be given to other complex road junctions around the world . The student magazine of Birmingham City University , Spaghetti Junction , took its name from the interchange's nickname, before being rebranded as Polygon . The development of
120-410: A right turn (across oncoming traffic) in one turn). It also allows for diagonal crossings ( pedestrian scramble ) and reduces crossing distances for pedestrians. Intersections generally must manage pedestrian as well as vehicle traffic. Pedestrian aids include crosswalks , pedestrian-directed traffic signals ("walk light") and over/ underpasses . Walk lights may be accompanied by audio signals to aid
144-559: A right turn on red, and sometimes left on red depending on the geometry of the intersection in question, possible in many cases, often without stopping. Cyclists ideally have a protected bike lane on the approach to the intersection, separated by a concrete median with splay kerbs if possible, and have a protected bike lane width of at least 2 metres if possible (one way). In the Netherlands , most one way cycle paths are at least 2.5 metres wide. Bicycle traffic can be accommodated with
168-415: A setback crossing of the pedestrians and cyclists , generally between 1.5–7 metres of setback, a forward stop bar, which allows cyclists to stop for a traffic light well ahead of motor traffic who must stop behind the crosswalk. Separate signal staging or at least an advance green for cyclists and pedestrians is used to give cyclists and pedestrians no conflicts or a head start over traffic. The design makes
192-638: A trip to Spaghetti Junction as a booby prize . In 2022, for the 50th anniversary of the opening of Spaghetti Junction, Heinz released a limited edition of their tinned spaghetti featuring the interchange on the tin. The under side of Spaghetti Junction was used for the homeless camp/stacks in Steven Spielberg's 2018 film Ready Player One . Road junction Roads began as a means of linking locations of interest: towns , forts and geographic features such as river fords . Where roads met outside of an existing settlement, these junctions often led to
216-909: Is a four-way interchange on the German autobahn network. Autobahndreieck (literally "autobahn triangle"), short form dreieck , and abbreviated as AD, is a three-way interchange on the German autobahn network. At intersections , roads cross at-grade . They also can be further subdivided into those with and without signal controls. Signalized designs include advanced stop line , bowtie , box junction , continuous-flow intersection , continuous Green-T, double-wide, hook turn , jughandle , median u-turn, Michigan left , paired, quadrant , seagulls , slip lane , split, staggered , superstreet , Texas T , Texas U-turn and turnarounds . Non-signalized designs include unsignalized variations on continuous-flow 3 and 4-leg, median u-turn and superstreet, along with Maryland T/J, roundabout and traffic circle . In
240-632: Is whether or not the roads cross at the same or different elevations . More expensive, grade-separated interchanges generally offer higher throughput at higher cost. Single-grade intersections are lower cost and lower throughput. Each main type comes in many variants. At interchanges , roads pass above or below each other, using grade separation and slip roads . The terms motorway junction and highway interchange typically refer to this layout. They can be further subdivided into those with and without signal controls. Signalized ( traffic-light controlled) interchanges include such " diamond " designs as
264-569: The A5127 (Lichfield Road/Gravelly Hill), and several unclassified local roads. It covers 30 acres (12 ha), serves 18 routes and includes 4 km (2.5 mi) of slip roads, but only 1 km (0.6 mi) of the M6 itself. Across five different levels, it has 559 concrete columns, reaching up to 24.4 m (80 ft). The engineers had to elevate 21.7 km (13.5 mi) of motorway to accommodate two railway lines, three canals and two rivers. In 1958,
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#1732844267050288-480: The Grand Union Canal , Birmingham and Fazeley Canal and Tame Valley Canal meet. Gravelly Hill Interchange appears in the 1973 Cliff Richard musical film Take Me High , where he plays a banker living on a barge on Gas Street Basin . Ken Dodd called the junction "the eighth wonder of the world", because "you get on and wonder how to get off". The National Lottery -based show Winning Lines featured
312-621: The Ministry of Transport commissioned the engineering firm Sir Owen Williams & Partners to investigate possible routes to connect the M6, the A38(M) and the A38 trunk road. The interchange's colloquial name, "Spaghetti Junction", was coined in 1965 by journalists from the Birmingham Evening Mail . On 1 June 1965, reporter Roy Smith described plans for the then unbuilt junction as a "cross between
336-638: The diverging diamond , Michigan urban diamond, three-level diamond , and tight diamond. Others include center-turn overpass, contraflow left, single loop, and single-point urban overpass. Non-signalized designs include the cloverleaf , contraflow left, dogbone (restricted dumbbell), double crossover merging , dumbbell (grade-separated bowtie), echelon, free-flow interchange , partial cloverleaf , raindrop , single and double roundabouts (grade-separated roundabout ), single-point urban , stack , and windmill . Autobahnkreuz (literally "autobahn cross"), short form kreuz , and abbreviated as AK,
360-640: The EU it is estimated that around 5,000 out of 26,100 people who are killed in car crashes are killed in a junction collision, in 2015, while it was around 8,000 in 2006. During the 2006–2015 decade, this means around 20% of road fatalities occur at junctions. By kind of users junctions fatalities are car users, 34%; pedestrians, 23%; motorcycle, 21%; pedal-cycle 12%; and other road users, the remaining. It has been considered that several causes might lead to fatalities; for instance: A number of features make this protected intersection much safer . A corner refuge island,
384-695: The Tame itself is 3 + 1 ⁄ 2 miles (5.5 kilometres) long, which makes it the longest viaduct in Great Britain, being 1 ⁄ 4 mile (400 metres) longer than the Second Severn Crossing . It was constructed during the period 1964–1972. Between 2012 and 2014, the motorway along the length of the viaduct was converted to a smart motorway system, with variable speed limits. 52°30′22″N 1°49′44″W / 52.506°N 1.829°W / 52.506; -1.829 This article about
408-516: The following September, several motorists were found to have been driving illegally along it, and children had found it a useful shortcut to school. In early 1972, Viking Motors ran a return service from Burton-on-Trent to the interchange for 65p return. The junction was opened on 24 May 1972 by the then Secretary of State for the Environment , Peter Walker . The opening was delayed by several months because of "box girder inspections". These followed
432-559: The interchange was approved and announced in August 1968 by the then Minister of Transport , Richard Marsh . Construction was expected to take three years and to cost £8m. The contract was given to A. Monk Ltd, of Padgate , for £8,183,790 in August 1968. Work started in September 1968 on the 30-acre junction. Monk were also building part of the M3. The work was led by chief engineer Roy Foot. There were
456-509: The interim report of the Merrison Enquiry set up following the collapse of similar box girder bridges in Australia and Wales . Birmingham City Council saw the junction as a potential opportunity to attract visitors to the city, and proposed a Grand Prix involving the interchange. The junction has undergone major repair work several times since, owing to the very heavy traffic through
480-516: The junction and cost-saving measures during its construction. In November 2007, a slip road running from the Tyburn Road onto the Aston Expressway was closed for urgent repairs. Upon inspection, it was found that Spaghetti Junction itself was in need of repair, because salt and grit had weakened the joints in the structure. By 2009, it was estimated that 1.25 billion vehicles had travelled through
504-663: The junction, and although structural defects had been found, the overall structure was stable enough to continue carrying traffic. South-east of the junction, the M6 is on the elevated Bromford Viaduct – the longest viaduct in the UK. Underneath the motorway junction are the meeting points of local roads, the River Tame 's confluences with the River Rea and Hockley Brook , the Cross-City and Walsall railway lines and Salford Junction , where
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#1732844267050528-596: The low grade bike lanes in the roadway or higher grade and much safer protected bicycle paths that are physically separated from the roadway. In Manchester, UK, traffic engineers have designed a protected junction known as the Cycle-Optimised Signal (CYCLOPS) Junction. This design places a circulatory cycle track around the edge of the junction, with pedestrian crossing on the inside. This design allows for an all-red pedestrian / cyclist phase with reduced conflicts. Traffic signals are timed to allow cyclists to make
552-479: The visually impaired. Medians can offer pedestrian islands, allowing pedestrians to divide their crossings into a separate segment for each traffic direction, possibly with a separate signal for each. Bromford Viaduct The Bromford Viaduct carries the M6 motorway between Castle Bromwich (junction 5) and Gravelly Hill (junction 6 - Gravelly Hill Interchange ) along the River Tame valley in Birmingham , England. This elevated stretch of motorway above
576-521: Was to add traffic control devices, such as stop signs and traffic lights that regulated traffic flow. Next came lane controls that limited what each lane of traffic was allowed to do while crossing. Turns across oncoming traffic might be prohibited, or allowed only when oncoming and crossing traffic was stopped. This was followed by specialized junction designs that incorporated information about traffic volumes, speeds, driver intent and many other factors. The most basic distinction among junction types
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