M42, M25 and M16 Zones

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gepree68
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M42, M25 and M16 Zones

Post by gepree68 »

2021-06-24 M42 M25.png
2021-06-24 M42 M25.png (19.9 KiB) Viewed 1147 times
M42 starts in zone 4 and ends in zone 6.

M25 starts in zone 2, then it goes through zone 3 and zone 4, and ends in zone 1.

These two examples seem to show that an Mxx motorway's first number (in other words 4 for M42, and 2 for M25) must be the zone in which that motorway starts:
  • M42 starts with a 4 because it starts in zone 4
  • M25 starts with a 2 because it starts in zone 2
2021-06-24 M42 M25 M16.png
2021-06-24 M42 M25 M16.png (19.22 KiB) Viewed 1147 times
But I don't understand how this system would have worked when there were plans for both M25 and M16.

Following the same logic, M16 should also need to start with a 2, because (like today's M25) it passes through zones 2, 3, 4 and 1.

Was a different rule in place back then for what the first number of a motorway should be?

Or was M16 J1 going to be somewhere in zone 1 (rather than in zone 2)?
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Re: M42, M25 and M16 Zones

Post by Steven »

If only there were a website that had a whole load of information on how motorway numbering came to be, and how it works...

In addition, we simply don't know where M16 J1 would have been (unless Chris5156 or Truvelo have seen something I haven't).
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Re: M42, M25 and M16 Zones

Post by Chris5156 »

gepree68 wrote: Thu Jun 24, 2021 17:40But I don't understand how this system would have worked when there were plans for both M25 and M16.
It's unlikely that the people who devised the system for numbering motorways had any idea that there would ever be circular motorways that would pass through many zones, so their system made no account for it.

The short answer to all your questions, really, is that the idea there was ever a rigid system for numbering motorways is a fantasy. There was a system, once, which served to decide numbers for a lot of motorways. But there have always been exceptions and you cannot assume that everyone who ever had the job of allocating a number to a road even knew about the system, let alone followed it, nor can you assume that the system included rules to account for every possible eventuality.

Generally speaking a road takes its number from the furthest anticlockwise zone it enters, so M25 is entirely valid on that score, as is M42.

No junction numbers were ever allocated to M16, for the simple reason that on large parts of its route no decision was ever made about how many junctions there would be or where they would be located!
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Re: M42, M25 and M16 Zones

Post by Steven »

Chris5156 wrote: Thu Jun 24, 2021 18:28 The short answer to all your questions, really, is that the idea there was ever a rigid system for numbering motorways is a fantasy.
That's not quite true!

There was a rigid system, and it was used for the first few motorways. However, over the years since 1959, it's slowly fallen more and more into disrepair as edge cases that were never thought about came to be, as motorways were extended backwards into the wrong zones, and as the people who instigated the system retired or went to head up the Ministry of Silly Walks the new people didn't follow it quite properly, until we get to the point where actually the folk allocating numbers don't even know that there should be a system for it.

It's the same story as the all-purpose numbering system, until you end up with stupidity like the B38 in Birmingham, with the fix being the almost equally wrong B384.
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Re: M42, M25 and M16 Zones

Post by Chris5156 »

Steven wrote: Thu Jun 24, 2021 20:03
Chris5156 wrote: Thu Jun 24, 2021 18:28 The short answer to all your questions, really, is that the idea there was ever a rigid system for numbering motorways is a fantasy.
That's not quite true!
Yes, overstating it for effect and all that. But often the fact that there ever was a system is taken to mean that there is a system and that all numbers must somehow fit it. If only :shock:
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Re: M42, M25 and M16 Zones

Post by Truvelo »

Chris5156 wrote: Thu Jun 24, 2021 18:28
gepree68 wrote: Thu Jun 24, 2021 17:40But I don't understand how this system would have worked when there were plans for both M25 and M16.
It's unlikely that the people who devised the system for numbering motorways had any idea that there would ever be circular motorways that would pass through many zones, so their system made no account for it.
For the circular roads that exist, M25 M60 and Coventry Ring Road, the junctions are numbered clockwise so in theory they should be numbered at J1 which means the M25 and M60 are in zone.
Chris5156 wrote: No junction numbers were ever allocated to M16, for the simple reason that on large parts of its route no decision was ever made about how many junctions there would be or where they would be located!
For the M40-M11 section we know which would have been numbered M16 it would be in zone if the junctions were numbered from the M11 westwards but this would ago against the numbering of circular motorways. If the entire Ringway 3 was to be M16 and it followed the convention of junction numbering in a clockwise fashion then J1 would be at Dartford meaning it would be out of zone and should start M2x. However, as Chris mentions, it was scrapped before that sort of detail would ever be considered.
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Re: M42, M25 and M16 Zones

Post by gepree68 »

Chris5156 wrote: Thu Jun 24, 2021 18:28 Generally speaking a road takes its number from the furthest anticlockwise zone it enters, so M25 is entirely valid on that score, as is M42.
2021-06-25 M5 M6 M40 M42 M50.png
Let's say they built a motorway between the M5/M50 junction and the M40/M42 junction.

Would the number of the new road have to be either M50 or a new M4*, for example M43?

Pathetic.org.uk: Strensham Solihull Motorway
Roads.org.uk: Numbers for motorways
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Re: M42, M25 and M16 Zones

Post by Chris5156 »

gepree68 wrote: Fri Jun 25, 2021 17:21Would the number of the new road have to be either M50 or a new M4*, for example M43?

Pathetic.org.uk: Strensham Solihull Motorway
Roads.org.uk: Numbers for motorways
The two pages you linked to both suggest that a number in the 4-zone would be the only appropriate one for a road on that line. But that doesn't mean that - if it had ever reached that stage - a 4-zone number would necessarily have been chosen!
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Re: M42, M25 and M16 Zones

Post by Sunil_of_Yoxley »

The M25 only starts in Zone 2 because the A282 is all-purpose (though it probably needs to be!). If the Dartford Crossing were a Motorway, then of course the "M25" would start in Zone 1.

Of course, whether the M16 was supposed to have included the Dartford Crossing is another matter!
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Re: M42, M25 and M16 Zones

Post by Truvelo »

gepree68 wrote: Fri Jun 25, 2021 17:21 Let's say they built a motorway between the M5/M50 junction and the M40/M42 junction.

Would the number of the new road have to be either M50 or a new M4*, for example M43?

Pathetic.org.uk: Strensham Solihull Motorway
Roads.org.uk: Numbers for motorways
We already know what the likely number would have been. This would have resulted in the M42 number going the same way as M16 - to heaven. A continuous M50 would be in zone as it starts west of the M5.
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Re: M42, M25 and M16 Zones

Post by ais523 »

I think the most obvious plan for a Strensham-Solihull Motorway numbering would be to make it M42, and make the existing M42 west of the M40 into the M40.

I also think that this wouldn't be done in practice, due to the costs of changing all the signs in south Birmingham that refer to the M42. The most cost-effective solution would be to make it the M50 (and have the M50 terminate on the M42 at the M40 terminus).

It seems unlikely that such a road would be built at all, though; if extra capacity is needed in that area, the most likely strategy is to upgrade the A46. (Of course, this brings up the question of "if you upgrade the A46 south of the M69 to motorway, would it get renumbered M69?")
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Re: M42, M25 and M16 Zones

Post by the cheesecake man »

ais523 wrote: Sat Jun 26, 2021 05:14 The most cost-effective solution would be to make it the M50 (and have the M50 terminate on the M42 at the M40 terminus).
That would be the most likely answer, but what junction numbers would be used? :coat:

Alternatively perhaps the M40 could continue that way, leaving M42 and M50 unchanged.

Not that it's going to happen.
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Re: M42, M25 and M16 Zones

Post by Bryn666 »

What's that? M50 from Newport to Nottingham, you say? :o
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