Motorway numbering

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Guy-Barry
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Motorway numbering

Post by Guy-Barry » Mon Apr 22, 2002 18:08

OK, let's try to shed some light on this. I covered it in some detail in my "Organized Chaos" essay, and there are articles about it in various places on the Web, but it seems that some people aren't quite clear about the principles.
The zones for motorways are different from the zones for A- and B-roads (in England and Wales at least). With one or two exceptions, the zone boundaries are the M1 to M6, not the A1 to A6. The routes of the (M-numbered) motorways are not systematically related to those of the similarly numbered A-roads. If the M1 were an A-road, it would have a 5-zone number; the M5 would have a 3-zone number; the M6 would have a 4-zone number; the M18 would have a 6-zone number; the M27 would have a 3-zone number; the M32 would have a 4-zone number; and there are many other such examples. See the maps herefor the difference between the two zoning systems.
Obviously many motorways parallel the route of the similarly-numbered A-roads, such as the M2 and most Scottish motorways. But I wouldsay that most of them don't. I've just done a quick trawl of Richard's motorway list and I'd say that (being generous) about twenty do and about thirty don't. For the most part, the motorways were built to serve the industrial conurbations, whereas the low-numbered A-roads tend to serve the older settlements such as cathedral cities. You wouldn't necessarily expect them to have similar routes. In fact one point little remarked upon is how closely many motorways parallel major railway lines (e.g. the M4 runs via the railway town of Swindon rather than taking the A4's route via Marlborough).
So the reason why the M5 doesn't parallel the A5 is that it was never intended to. Birmingham is an important hub on the motorway network, and surely it's right that the two main motorwaysserving it should have single-digit numbers. (There is, of course, a motorway running parallel to the southern stretch of the A5: it's the M1. I wonder why no one ever suggests that this should be renumbered as the M5?)
Guy

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Chris5156
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Post by Chris5156 » Mon Apr 22, 2002 19:54

How very concise Guy :-)
The only thing I can possibly add is that the convention if numbering motorways after their corresponding A-roads (and I realise I'm clarifying and restating an existing point here) is done for convenience and not because of a rule. If it were, then we'd have M5 from Staples Corner to Telford, the M38 from Birmingham to Bristol and the M580 linking Manchester to Liverpool. Madness!
Chris

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Paul
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Post by Paul » Tue Apr 23, 2002 13:33

I don't like madness (but I do like Madness)...
A38
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Paul

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Tom
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Post by Tom » Sat Mar 01, 2003 18:59

Time to resurrect this thread, as I went to the Public Records Office in Kew today, and one of the things I looked at was a file on motorway numbering (MT112/67 if anyone wants to look it up himself).
It seems that the numbering scheme was decided quite late in the day, during the summer and autumn of 1959 (just before the first section of M1 opened in November).
Some interesting (to me, anyway) points:
  1. The merits of zone-based (as with the A-roads) and tree-based numbering (whereby spurs off the M1 were given a M1x number regardless of which side they left the motorway) were debated. Some people thought that it was silly toname the M45 after a motorway that was going to be 100 or so miles away, as happens in a zone-based system. Zones prevailed, however.
  2. M1-M4 were going to radiate out of London and divide England into quarters. M7-9 were apportioned to Scotland for consistency. This left the M5 number free for the important route from Birmingham to the South West, and the M6 number for Midlands - North West, with the additional benefit that it shadowed the A6 for much of the way.
  3. Spurs and other motorways within the zones were going to be two digit numbers -- it was not thought that the network would be big enough for three-digit numbers.
  4. There seems to have been a big panic to get the M1/M10/M45's numbers allocated during the summer of 1959 (signs would have to be made, map-makers would have to be notified etc.) The M1 was a fairly easy choice, the M10 was chosen as it was going to be the southernmost spur of the M1, and the M45 chosen to allow more spurs and motorways further south (M40, M41, ..., M44) and further west (M46, ..., M49). There was also the convenient fact that it shadowed the A45.
  5. The M2 number proved trickiest to allocate amongst the 1-digit motorways: some thought it should be the London-Brighton motorway (as it was of more importance, and more likely to materialise in its entirety than the Channel Ports motorway (don't ask me why!)) and the upcoming Medway Towns bypass should be designated A2(M). However, others disagreed, seeing that the zonal boundary would be best just south of the river,incidentally shadowing the A2, and proposed the M23 numbering for London-Brighton. When the new Medway Towns bypass was announced (December 1959), the Daily Telegraph went so far as to assume it was to be called the M2, even though this hadn't been decided by the MoT at this stage.
  6. As the M3 was originally intended to go to Exeter (roughly along the line of A303/A30 from Basingstoke), the 2-zone / 3-zone boundary ran along here to Exeter, and indeed to Plymouth. Now, as we know the M3 didn't go that way in the end, but is that still the boundary of the 2/3 motorway zones? This would explain the numbering of the M271 (or it could be a relic of the tree-style numbering system, being a spur off the M27).
  7. Motorway-standard bypasses as part of the principal (i.e. 'A') road network. The nomenclature for these was thrashed out in a meeting on 03/07/59. The original Anderson committeeproposals for signs on 'A' roads approaching motorways were to give them a blue panel for the directions concerning the motorway (much like patching today). This would have meant that the Doncaster bypass (for example) could have been continuously signed as A1, and the presence of the blue background would be sufficient to denote its motorway status (along with the 'No stopping' etc signs). However, the Anderson committee changed its mind and proposed all-blue signs for roads approaching a motorway junction, so if you were approaching (from an 'A' road) a sign that had a blue background and 'A' roads only marked on it, you wouldn't know which road was motorway standard. Hence, a Mr Wykes at the MoT put forward the (M) designation we all know and love today. Arguably, since all-blue signs are no longer required, we could lose the (M) now, as the blue background would be sufficient.
  8. The Preston Bypass was numbered M6 right from the start. This was against the policy decided in 1959, under which isolated stretches of motorway bypass should be given an Ax(M) designation until they were joined up, but seeing as it had already been numbered M6 when it opened in 1958, the MoT was not going to change it. Indeed, it perpetuated the difference, as the Lancaster bypass was also numbered M6 as it was decided that the inconsistency between two bits of the same motorway a few miles apart was unacceptable.
  9. The number for the North and South Orbitals of London was debated, as performing a circuit around the 1-4 zones it would be a special case. The name M15 came from M1to5, from the zones it passed through (even though this was wrong, as the 5-zone was nowhere near London!!). M45 was also mooted, as a shortening of M405 (motorways weren't to have three digits). The number M25 was first proposed by a Mr Lovatt in 1960.
  10. The northern terminus of the M1 was debated. Some thought that the M1 should go along what is now the M18, and another number be used for the extension to Sheffield and Leeds. Wakefield town council thought otherwise, as did many other MoT- ites.
  11. Some interesting proposed motorway numberings (many of which were abandoned through the course of the file I was looking at): <TABLE borderColor=#000000 cellSpacing=1 cellPadding=1 border=1> [tr] [td]M30[/td] [td]M4 Heathrow spur[/td][/tr] [tr] [td]M46 (I also saw M41, which seems more logical)[/td] [td]M4 spur at J7[/td][/tr] [tr] [td]M47[/td] [td]A404(M)[/td][/tr] [tr] [td]M19[/td] [td]The M62 from the M1 eastwards. Originally the junction of the M62 and the M1 was going to be a dog-leg, but this was changed to the current layout and the M62 number given to the whole motorway.[/td][/tr] [tr] [td]M61[/td] [td]The Castle Donnington bypass (at M1 J24)[/td][/tr] [tr] [td]M58[/td] [td]Preston southern bypass (now part of M65 I think)[/td][/tr] [tr] [td]M59[/td] [td]Blackpool spur -- this makes some sense as it's the northernmost spur in the 5-zone[/td][/tr][/table]</OL> This is a quick summary of what I read. I may have misunderstood some bits, or skated over vital amendments, but I think this sums it up pretty well (I'm sure JNW will correct me if I'm wrong). Hope I haven't bored anyone to tears!
    Tom

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Post by Tom » Sat Mar 01, 2003 19:05

The scope of the file I looked atwas supposedly up to 1968, though I don't think there was anything in there from much after 1962-ish. I'm going to try and see if there's anything related later than this.

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