The M11 motorway is a 52-mile (88.5 km) motorway that runs north from the North Circular Road (A406) in South Woodford in northeast London to the A14, northwest of Cambridge, England. Originally proposed as early as 1915, various plans were considered throughout the 1960s, with final construction being undertaken between 1975 and 1980. The motorway was opened in stages, with the first stage (between Junctions 7 and 8) opening in June 1975, and the completed motorway becoming fully operational in February 1980. Running from South Woodford to Girton, the motorway provides direct access to Harlow, a large new town, as well as the city of Cambridge and since 2002, the motorway has greatly improved access to London Stansted Airport, the fourth busiest airport in the United Kingdom.
The M11 starts in South Woodford in northeast London at Junction 4, with the North Circular (A406), it then heads NNE, passing east of Loughton and Theydon Bois as well as Epping Forest, meeting the M25 motorway at Junction 6, and then veering approximately north, passing to the east of Harlow. The M11 gives access to Bishop's Stortford and the motorway's only service station via Junction 8. This is followed immediately by the recently constructed Junction 8A, which provides a free-flow link to the improved A120 that links to Stansted Airport. The M11 then traverses part of Cambridgeshire, meeting a spur for the A11 at Junction 9, and then finally ends at Junction 14, the busy Girton Interchange, with the road continuing through the junction and becoming the A14, which continues the route on to Huntingdon and the north.
The motorway starts with two lanes southbound and three northbound; then, north of Woodford Bridge, both directions have three lanes, a layout that continues up to Junction 8A, except for a brief two-lane section at Junction 6, beneath the M25. From Junction 8 the motorway has two lanes in both directions all the way to Junction 14 where the motorway terminates. The motorway is illuminated at the southern terminus near Junction 4, at Junction 6 (the M25 interchange), and also at the approach to Junction 8/8A (Stansted Airport/Bishop's Stortford), and then at the northern terminus at Junction 14, for the A14. All four of these sections use modern high pressure sodium (SON) lighting. The older, yellow, low-pressure sodium (SOX) lighting originally used at junctions 4 and 6 was replaced in 2005. The numbering of the M11 junctions is unusual, as 1–3 are neither used nor shared with another road (see 'History' section). This means that southbound drivers reaching the end of the M11 have to use the A12 & A11 to reach central London.
Plans for an 'Eastern Avenue' in London had been proposed as early as 1915, and the Eastern Avenue Extension was causing local concern in Leyton and Hackney during the late 1950s and early 1960s. It was opposed by a number of groups, including the Hackney Society and local residents as represented by their member of parliament in 1962.
By 1966,the Ministry of Transport was planning a longer road and for it to be partly motorway. The first version had a mid-south section, to follow a River Lea route, starting at Angel southwest of Dalston, heading northeast then north, taking land by the river in Walthamstow, Chingford and Waltham Cross, and meeting the built road alignment of today north of Harlow. The road from South Woodford to Islington would have been designated as the M12. The route was in planning stages with several options, with differences between the plans preferred by the Greater London Council and the Ministry of Transport – a different version called for this 'Eastern Avenue' to run more east–west alongside the Regent's Canal and the north side of Victoria Park, Hackney Wick, where it would have connected to the North Cross and East Cross Routes at the northeast corner of an inner ringway identified by the London Ringways plan.