:''This article is about a planned motorway in England. For the M15 motorway in Hungary see M15_motorway_(Hungary)''
The '''M15 motorway''' was the designation planned in the late 1960s and early 1970s for use on the North Circular Road (A406) after it had been upgraded to Motorway standard. The upgrade was part of the London_Ringways Plan to build motorways throughout London to ease congestion in the central area. Under the Ringways Plan, the North Circular Road was the northern section of Ringway_2.
Most of the Ringways plan was cancelled in 1973 and the upgrade of the A406 took place in a piecemeal fashion during the following three decades. Although much of the road is now grade separated Dual_carriageways, the improvements have not been carried-out to motorway standards and there are still a number of sub-standard sections and many junctions with minor roads.
One section of the M15 was constructed in the early 1970s in conjunction with the M11_motorway. The section of A406 between M11 junction 4 and the Redbridge interchange with the A12 was opened as the southern end of the M11 and the Redbridge junction was designated as M11 junction 3. This was a temporary designation to avoid driver confusion, because, at the time of opening, traffic entering this section of road northbound from the Redbridge Roundabout could only continue onto the M11 and traffic heading southbound on the M11 could only enter the section to Redbridge. To have used two motorway numbers for what was effectively one route would have caused difficulties.
As the A406 motorway upgrade was not constructed, the designation has never been officially used.
==External links==
* Pathetic Motorways - M15
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