It goes by the less-than-snappy name of "A-road with motorway restrictions". M25 - this is the 117-mile motorway that almost forms a complete circle around Greater London. (The answer is at the bottom if you need it - no peeking please. Once these routes were connected it's a fairly safe bet that they would have become a continuous route and the whole thing would have been given one number.The question is - given that motorways are expected to travel clockwise around the hub-and-spoke system, which zone would this motorway take its number from? If you've managed to get this far without breaking into a sweat, you might like to tackle this question.In the 1960s and 1970s, a motorway route was proposed across Worcestershire and Warwickshire, connecting the M50 at Strensham to the M69 north of Coventry (see left). It can be explained in three steps, including the whole process of selecting a route and constructing the road, which is quite impressive. The list of motorways in the United Kingdom is a complete list of motorways in the United Kingdom. Motorway driving is the skill British people say they lack confidence in ... More than 70 firefighters tackle huge warehouse blaze in north London Environment. This is never less obvious than with the case of the Great North Road. There is also no geographical or chronological system: from south to north the zone 5 routes are M50, M54, M56, M53, M57, M58, M55; the last zone 6 number to be allocated was M60. So no zone 5 or zone 6 motorway can enter zone 4, but a zone 4 motorway can enter both zones 5 and 6.No number was ever assigned to the proposal, but M46 would probably be most appropriate.Last year we reported on an experimental "3D" zebra crossing. The following motorways were planned, but never built. )So from chaos to simplicity: the Scottish motorway numbering system is a piece of cake.
When the Bypass became part of M20 the old road reverted to A20 again. The first is the consideration that any motorway that replaces a short A-road gets a ridiculous number: M876 is a vital link in Scotland's motorway network, but it parallels the A876 and therefore it gets an outrageous number even though all the numbers M81 to M89 are unassigned.Slightly more problematic is what happens if you build a motorway on a whole new line, not parallel to an A-road. By the late 1950s, Scotland was looking after its own trunk roads, thank you very much, and so we will turn to Scottish motorways in a moment. It has been bypassed many times by various isolated sections of motorway, but because the number M1 has long since been taken, its bypasses - even when connected to form lengths of thirty miles or more - will forever rejoice in the instantly-forgettable name A1(M).The new motorway between M50 and M69 would have to have a number beginning with a 4, despite poking out of zone 4 at both ends. The M90 motorway, Britain's northenmost motorway, runs from Edinburgh to which city on the River Tay? Roads which used to be motorways but have been downgraded: It's meant to, anyway: the opening of the A20(M) Maidstone Bypass caused the old A20 through the town to become A2020. It almost makes up for the England and Wales system. There is literally no system to determine which number a road should get within a given zone.The twisted logic of motorway zones in England and Wales is bad enough as it is. This page documents it in detail.Original text, photographs and graphics © 2001-2020 Chris Marshall, except where stated. There is also some doubt about whether the M3 forms the zone boundary all the way to Southampton, or whether the 3/4 zone boundary takes an arbitrary line south-west from somewhere around Basingstoke.There are two further routes, dividing what would otherwise be an extraordinarily large zone 4 into smaller pieces:This is where you might need to take a couple of aspirin. So A20(M) ate its vegetables, grew up to be big and strong and now goes by the name M20. Despite initial plans to number motorways as part of the A-road network (where, for example, the A50 was proposed for what is now the M1), it didn't take long for the idea of separate numbers with the prefix "M" for motorway to catch on.This page looks at how those numbers are allocated across Great Britain, and also how those pesky A(M) numbers work.The first surprise is that it's actually two systems.