Talk:Anomalously numbered roads in Great Britain

Definition of anomalous
The meaning of "furthest-anticlockwise" needs to be specified more precisely in order to establish the concept of anomalousness. For the M25 the crucial point is that it does not directly pass between zones 1 and 2. If it did so, but instead had a small gap somewhere else, this would not change its list of zones; the order in which they occur is significant. The A202 seems to link zones 2 and 5 without passing through zone 4. On what basis is zone 2 more anticlockwise than zone 5? One answer (which is also consistent with the M25) is that you always start looking from zone 1 and go anticlockwise towards zone 2. On this basis the (unlisted) A202 is indeed not anomalous, but neither is the (listed) A282. The A100, A101 and A102 would become anomalous instead only if the boundary between zones 1 and 2 is taken to be The Thames exactly, rather than the first main road running along its south bank. —Preceding unsigned comment added by 82.24.163.22 (talk) 00:41, 22 March 2009 (UTC)
 * In England and Wales, "furthest anticlockwise" is precisely defined for a road which is continuous (or whose missing links are so obvious they can be assumed) and does not cross all six zone boundaries. If the road lies within one zone then the prefix is obvious.  If not then it must cross a set of boundaries which are adjacent on the circular list (1:2, 2:3, 3:4, 4:5, 5:6, 6:1, 1:2, ...), even if the boundaries are multiplexed together or the road crosses them multiple times.  The first number of the first boundary crossed gives the correct prefix.  A similar argument applies for the five boundaries (1:6, 6:7, 7:8, 8:9, 9:1) in Scotland, though there may be a theoretical ambiguity where a road crosses the 1:6 boundary at the border with England.  This analysis, of course, is pure WP:OR.  The A282 is anomalous because it crosses only 1:2 and should be in zone 1.  The A202 crosses only 2:3 and is correctly in zone 2.  I can not see where the A202 enters zone 5, but if it did so west of London it would cross boundaries 2:3, 3:4 and 4:5 (an adjacent set starting with 2:) and still be numbered correctly. Certes (talk) 22:10, 22 March 2009 (UTC)

M48
Is it numbered wrong? Its fully within zone 4 (comment left by 172.216.154.237 on 18th April 2006)


 * The article appears to be correct that the M48 is in zone 5. Zone 5 is the entire area west of the M5 but south of the Scottish border. Zone 4 is the area north of the M4, east of the M5, south of the M6 and west of the M1. As the M48 is west of the M5, it should be in zone 5. Road Wizard 20:25, 20 April 2006 (UTC)


 * The M48 is no where near zone 5!
 * http://en.wikipedia.org/wiki/Great_Britain_road_numbering_scheme
 * Do your reserach, any thoughts or I'm changing it. —The preceding unsigned comment was added by 81.159.59.186 (talk • contribs) 19:14, 13 May, 2006 (UTC).


 * What you are refering to is "A" road zone 5, which is defined by the boundaries of the single digit "A" roads. Motorways have their own zone system based on the layout of the single digit motorways. The zones may be broadly similar for most of the country, but the zoning system is certainly different as far as it covers the west coast of England and Wales. Using the motorway zoning system, the M48 is technically in zone 5. Road Wizard 02:33, 14 May 2006 (UTC)


 * It's a matter of debate whether the zone boundary changes at all if a single-digit road is re-aligned. It's certainly north of the M4 now, but was once the M4, and I would suggest that it's probably appropriate that it has a M4x number. Also, it's difficult to determine exactly where the 3-zone/4-zone & 5-zones are in the South West/South Wales - there is little evidence on the ground (few motorways). I have certainly seen evidence that the motorway zones were devised very late on - certainly after the opening of the Preston Bypass in 1958. There is also evidence that I've seen that the 2-zone/3-zone boundary follows the rough route of the A30 or A303, rather than the M3. Richard B 23:23, 8 August 2006 (UTC)


 * I am not questioning the appropriateness of the numbering of the M48. Most modern road numbering follows the pattern of convenience for the travelling public rather than strict adherence to the rigid zone structure. If you look at the anomalies listed in this article, I suspect you could find valid reasons for most of them as to why they are appropriate. However, this article is intended to list anomalies to the system no matter how appropriate they are. Yes the zoning system is somewhat confused along the west coast of England and Wales, but the M48 does share zone space with the M50. Either the M48 is anomalous to the system or the M50 is (or perhaps even both). Road Wizard 02:35, 9 August 2006 (UTC)


 * I've just seen the original proposal for the motorway zones, dated about 1960; it does suggest that the M48 is the 3-zone/5-zone boundary on the English side of the Severn Bridge, and that on the Welsh side - it lies entirely within the 5-zone (along with the rest of Wales). The motorway 4-zone is the region enclosed by the M1/M6/M5 and M4. So the M50 is correctly in its zone, the M48 should have a 5-zone number, and the M49 does lie entirely within the 3-zone. Richard B 11:14, 1 September 2006 (UTC)

M25
Is the M25 really numbered wrongly? It begins in the 2 zone, so takes a 2 number regardless of which zone it ends up in. Owain 08:55, 28 July 2005 (UTC)


 * Yes, that is correct. It starts in the 2M zone, and then moves clockwise into the 3M, 4M and 1M zones. GCarty 08:57, 28 July 2005 (UTC)


 * Well, I think it should still be included. But at least it gets a mention here. -- RHaworth 17:19:32, 2005-08-02 (UTC)


 * What confuses the issue is that (like for a lot of roads in Kent) the A2 is NOT the grid boundary. So the M25 starts between the A1 and the A2 and you'd expect it to be a Zone 1 road unless you realise the boundary isn't the A2. Cheers, Wol


 * The summary of the system explains, "The first digit of a road's number should be the number of the zone it occupies. If the road occupies multiple zones, then the furthest-anticlockwise zone is the correct one." No mention is made in this definition of directionality in terms of numbering of junctions. Zone 1 is farther anti-clockwise than zone 2.  In what way, therefore, is the M25 not anomalous?  Kevin McE (talk) 17:28, 29 October 2017 (UTC)


 * As GCarty said in 2005, the M25 starts in Motorway Zone 2 (the zone 1/2 boundary presumably being the Thames), so its numbering follows the rules. Mdrb55 (talk) 17:00, 8 January 2019 (UTC)

A604(M)
I question the existance of this road. The only section I can think of that this could mean is the A14/A1(M) spur at Alconbury, but the section from Huntingdon to Haverhill (Through Cambridge) has not been the A604 since the A14 was re-numbered.

As a resident of the county in which this road is supposed to exist, I have no knowledge of it existing wither now or at any time in the past. Could someone please either confirm for or against and remove it if neccessary. - Burwellian 13:46, 4 August 2005 (UTC)


 * I don't know if the A604(M) still exists, but there was one in 1993. I dug up a Statutory Instrument that refers to it at that time: The A604(M) Motorway (Alconbury to A1(M) Section) And Connecting Roads Scheme 1993. Road Wizard 23:21, 14 April 2006 (UTC)

Boldness - an apology
I missed the line about the importance of the boldness. You might want to revert my edit. Erath 14:00, August 21, 2005 (UTC)


 * It's OK - I've put the bolding back the way it should be, while retaining the rest of your welcome additions. --GCarty 16:45, 7 September 2005 (UTC)


 * Ta muchly. I don't feel half as stupid now! Erath 19:06, September 7, 2005 (UTC)

A594
Might want to stick A594 road here, as its the only example I know of a duplicate road number. Morwen - Talk 15:23, 9 September 2005 (UTC)


 * No there are other duplicate roads, which you can read about here. They should really be on a new page, as this page is devoted to out-of-zone roads. GCarty 19:10, 9 September 2005 (UTC)

This article should be renamed
I think "Incorrectly" numbered roads is misleading - surely the numbers are correct, since they are the designated numbers given to the roads in question. "Inconsistently numbered roads" is a better choice, IMHO, since the numbering is inconsistent with the official system. Comments? TH 08:54, 16 September 2005 (UTC)


 * I'll Support that. - JVG 12:37, 16 September 2005 (UTC)


 * Renaming to "Anomalously numbered roads in Great Britain"... --GCarty 18:32, 16 September 2005 (UTC)

A601(M)
This doesn't really fit into any of the categories listed; but the A601(M) should be the name of the a601 under motorway regulations. Infact, it is a small spur of the M6 near Carnforth; the A601 is in Derby! Should a new box be created for this?Robdurbar 08:26, 19 September 2005 (UTC)


 * It would be interesting to know when the A601 and the A601(M) were built/redesignated to see which was mistakenly numbered. I think the A601(M) was given its new number in 1970, as this would have been when it became a spur of the M6 due to the extension of the motorway into Westmorland (present day Cumbria). Does anyone know when the A601 was built? Road Wizard 22:18, 20 April 2006 (UTC)

Irregularities not based on the zoning system
This section mixes duplicate roads with roads which seem to be included simply because they are many miles from roads with similar numbers. I suggest that a more complete list of duplicates would be worth including but the other entries are not useful. Could we rename the section as something like "Duplicate road numbers" and fill it out? External links such as should help. Certes (talk) 00:40, 5 December 2008 (UTC)
 * It would be useful to also list roads "many miles" from similar numbered roads - by definition they have been irregularly numbered (see A598 for example). best, Sunil060902 (talk) 12:08, 5 December 2008 (UTC)
 * Do you have a source for that definition? It would only be irregularly numbered if it goes against the defined rules for road numbering. Road Wizard (talk) 20:32, 5 December 2008 (UTC)
 * While there is no official rules (other than the zones) as to which roads get numbered, it can be observed that in general "batches" of numbers are allocated to specific areas (e.g. A44x, A45x to the Midlands). Even if it's not in such an official table, I feel it is worth mentioning, with a few obvious examples. It shouldn't be taken too far though (Pointing out the A4071 is a distance away from other A407x's is a bit extreme as they are relatively unimportant roads. jenuk1985 (talk) 20:58, 5 December 2008 (UTC)
 * Yes, I would draw the line at three-digit A-roads. best, Sunil060902 (talk) 01:02, 7 December 2008 (UTC)

Many three-digit decades like A10x are close in position, probably because the 1922 scheme tended to number roads in order from London outwards. Other decades like A50x were allocated or re-allocated later and are spread evenly through their zone. A few like A40x are mainly close with one or two exceptions. Perhaps we should only include the latter type, e.g. A403 but not A500. Sabre may be useful if we wish to find other, similar cases. Certes (talk) 00:27, 8 December 2008 (UTC)
 * I disagree with the A50x, only the A500 and A506 are found north of Birmingham, but I think the current list has them all! By the way, I'm on SABRE too! best, Sunil060902 (talk) 18:06, 8 December 2008 (UTC)

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A414
In what way is the A414's numbering anomalous? It starts in zone 4, and continues into zone 5, possibly zone 6, and zone 1. That is OK according to my understanding of the rules. Mdrb55 (talk) 17:03, 8 January 2019 (UTC)
 * Zone 1 is the farthest anticlockwise of all the zones, therefore the farthest anticlockwise that this road enters. It 'should' be the A1xx Kevin McE (talk) 19:12, 11 January 2019 (UTC)
 * A414 is perfectly fine, it starts in the "4-zone" heading clockwise into the "5-zone", "6-zone" and "1-zone". The zones go clockwise around London, NOT anti-clockwise. Best, Sunil060902 (talk) 22:51, 16 January 2019 (UTC)
 * The zones do indeed go clockwise around London, which is why zone 1 is the zone which is most anti-clockwise. So according to the stated rule, "If the road occupies multiple zones, then the furthest-anticlockwise zone is the correct one," the A414, by virtue of being in part in zone 1, is anomalously numbered.
 * If that is not the rule, then the rule needs a much clearer explanation. Your response seems to suggest that roads are considered to run clockwise or anti clockwise, an assertion that is meaningless unless the centre of the imagined circle is described (and such a centre would have to be equidistant between the two ends of the road).
 * By what evidence is it determined that the road runs 'from' Hemel Hempsted 'to' Maldon rather than vice versa?
 * And what reference is there for the stated criteria?
 * P'raps I should clarify. Take the A414, it travels clockwise through four zones, namely "4-zone", "5-zone", "6-zone" and "1-zone". A total of FOUR zones, correct? Of these four zones, the "4-zone" is the one that is most anti-clockwise, correct? Therefore, the A414 should start with a "4". Therefore it is correctly numbered, and should NOT appear in this article. Conversely, the A14 travels clockwise through a total of THREE zones, namely, the "5-zone", "6-zone" and "1-zone", correct? Of these three zones, the "5-zone" is the most anticlockwise, and it is for that reason that the A14 should really begin with a "5", and it is for that reason it's listed in this article. Best, Sunil060902 (talk) 23:33, 16 January 2019 (UTC).
 * OK, thanks, but where is the reference for this as being normative? How is it described in the official Department of Transport documentation, because the current description here is very unclear.  And how does this relate to roads in 6 and 7, which share no centre? Kevin McE (talk) 08:08, 17 January 2019 (UTC)

M62
I'm obviously missing something or misreading the criteria, but as the M62 crosses (extensively) into Zone 1, why is the anomaly that it should start 5, rather than 1? Julianhall (talk) 14:49, 11 November 2021 (UTC)