A flyover is neither a bridge nor a viaduct.
A flyover is a road carried over another road at an intersection.
To make it into my big list it's probably got a name like The Something Flyover.
Gallows Corner Flyover Where is it? Between Gidea Park and Harold Wood in Havering. [map][photo] What's the name about? This is where the Liberty of Havering had its gallows. What crosses what? The flyover links the A12 Eastern Avenue with the A127 Southend Arterial Road across the Gallows Corner roundabout. Traffic intending to stay on the A12 has to use the roundabout. When was it built?1970, by Terry and Co from prefabricated units. It was intended to be temporary but half a century later it's still here. It's not a smooth ride, there are sudden changes of gradient. Why is it still here? Plans to build the M12 between Woodford and Brentwood came to nothing. Also despite serious corrosion it's been repaired just enough to avoid being condemned. What's the weight limit? 7.5 tonnes. No buses go up and over. What's its future? TfL would like to repair it but it's expensive. A bid for government funding in early 2020 floundered because of the pandemic. They intend to submit a business case for refurbishment and strengthening to the DfT this summer.
Chiswick Flyover Where is it? Chiswick, not far from Kew Bridge. [map][photo] What crosses what? The M4 launches over the Chiswick roundabout then runs directly above the A4. When was it opened?1959, by Hollywood actress Jayne Mansfield. It was built by Alderton Construction and cost £820,000. Originally it just leapt over the (new) roundabout and back down again, but in 1964 it was extended westwards via a two mile viaduct which brought the M4 directly into inner London. What's it like? It's more a Brentford Flyover than a Chiswick Flyover these days. It still feels a bit futuristic zipping between elevated offices, glitzy billboards and shiny showrooms. It'd be less congested if it was wider. What's its future? They started essential stability works to the concrete structure last week, and these continue until May with several overnight closures.
Hogarth Flyover Where is it? Beside the Griffin brewery at the Hogarth Roundabout, less than a mile from the Chiswick Flyover. [map][photo] What's the name about? The artist William Hogarth lived very close by, in a historic house you can still visit free every day except Monday.
What crosses what? The A316 crosses the A4, northbound only. When was it opened?1971, as a temporary measure. It's strengthened with diagonal cross-braces. It's quite similar to the Gallows Corner prefabricated span. What's the weight limit? Only 3 tonnes. What's its future? The flyover underwent substantial repairs in 2014 so should be OK for now.
Marylebone Flyover Where is it? The clue's in the name. [map][photo] What crosses what? The A40 Westway crosses the A5 Edgware Road. When was it opened?1967, as part of the LCC's carving of the Westway across North Kensington. But it's separate from the rest of the Westway, which after two miles on stilts dips briefly back to street level before launching again. Look out for the commemorative plaque on the southeast flank.
Hammersmith Flyover Where is it? Bang in the middle of Hammersmith. [map][photo] What crosses what? The A4 crosses the edge of Hammersmith town centre allowing main roads and pedestrians to pass freely underneath. When was it opened?1961, at a cost of £1.2m. It was given the green light by transport minister Ernest Marples whose construction company won the contract. It's a very early example of a reinforced concrete flyover. It contained special electric cables for internal heating. What's its future? It's a bit of a money sink, having had to be closed for a prolonged period in 2012 due to water ingress. Repairs continued until 2015 which should hopefully last a few more years. Nearby Hammersmith Bridge is enough of an engineering nightmare to be getting on with.
Lodge Avenue Flyover Where is it? East of Barking. [map][photo] What crosses what? The A13 crosses a roundabout where Ripple Road meets Lodge Avenue. When was it opened?1966, as a temporary structure with a minimum design life of fifteen years. It's still operational but looks like it shouldn't be. What's the weight limit? 7.5 tonnes. What's the artwork underneath? That's HoldingPattern, an array of 76 stainless steel needles each topped by a blue airport taxiway light, part of Barking & Dagenham's A13 Artscape project.
Brent Cross Flyover Where is it? Brent Cross, just east of the shopping centre. [map][photo] What crosses what? The A41 Hendon Way crosses the A406 North Circular. When was it opened?1965, to relieve one of London's worst bottlenecks. It comprises 19 bridges, a flyover, subways, retaining walls and culverts to thread the River Brent underneath. What's its future? A 7.5 tonne weight limit was imposed last October for safety reasons. TfL are hoping for £50m from central government for extensive structural remedial works.
Bow Flyover Where is it? Between Bow and Stratford. [map][photo] What crosses what? The A12 crosses the A11 (or what was the A11) plus the River Lea. It links Bow Road to Stratford High Street. When was it opened?1967, inspired by the success of the concrete flyover at Hammersmith. Part of the East Cross Route, a Ringway scheme which would have encircled (and mutilated) many inner London suburbs. What's its future? After two cyclists died at the Bow Roundabout in 2011 TfL came up with a grand 'Vision for Bow' which might eventually have seen the flyover demolished to make way for a big crossroads. Instead we got a few pedestrian crossings underneath as part of an 'Interim Scheme' that now seems to be permanent, so the flyover's going nowhere. A rarity on today's list because it appears to have been well built so has no weight limit and is hardly ever closed.
Croydon Flyover Where is it? Just south of Croydon town centre. [map][photo] What crosses what? The A232 crosses the High Street and the A236. When was it opened?1969, as part of an unfinished ring road plan. The late 1960s/early 1970s really were peak flyover.