Sorry, wrong number

Published on 03 May 2024

Road numbering is a system with clear rules. Unfortunately the people responsible for numbering roads don't always follow them - or even, sometimes, seem to care there's a system at all.

100 years of road numbers

Our year of celebrations to mark the centenary of UK road numbering has run on for slightly more than a year now - but who's counting? We're bringing the season to a close by exploring some incorrect and unhelpful numbering mistakes.

You wouldn't think it could go too badly wrong. Not only does the system come with rules to tell you what sort of number is appropriate in different situations and different parts of the country, there are also literally thousands of examples that demonstrate how it looks when it's done right.

Then again, maybe the fact that it looks easy is why it isn’t taken very seriously.

You might think a badly chosen number doesn't matter, and sometimes it doesn't. The present A42, for example, was applied to a road between Tamworth and Nottingham in the 1980s. It lies entirely within zone 5, so it should have a number beginning with a 5, so it’s technically wrong - but the downsides of calling it A42 are few, and outweighed by the navigational benefits of it forming a continuation of the M42. Choosing a number that breaks the rules, for pragmatic reasons, might be a good choice. The world still turns.

What we're here to discuss is much more interesting: bad numbers that were created for terrible reasons, or even for no reason at all. By looking at them in detail we might learn a little bit about why road numbering actually matters. But first, let's take a moment to remember how numbering is meant to work.

Zones for A- and B-roads in Great Britain. Click to enlarge
Zones for A- and B-roads in Great Britain. Click to enlarge

Rules of the road

We've got a whole long-form article about road numbering that explains the rules in detail, and if you haven't seen it before then you should take a look, because - to those with a nerdy mindset - it's surprisingly interesting. (If you are already reading this, then I'm sorry to have to break the news: you have a nerdy mindset.) Here's a quick version of the basics for Great Britain.

  • There's a zonal system that means the first digit of a road's number is chosen by its location. The zones for motorways are different to the zones for A- and B-roads.
  • The length of a road number can hint at a road's importance. Shorter numbers are often for more important roads. So motorways can have one, two or three digits, and A-roads can have one, two, three, or four digit numbers - but B-roads can only ever have three or four digit numbers, indicating their lesser significance.
  • A number might be chosen for its similarity to other nearby numbers, helping it fit into a local pattern, but that should never override the rules of the zonal system.

There's another unwritten rule of the numbering system that haunts those of us who care about these things. It's that nobody cares about these things as much as road geeks do.

Whatever the rules might be, and whatever the advantages of a neatly ordered system, there is no enthusiasm for them in the corridors of power. The engineer who is given the task of choosing a new road number will have no interest in whether it's right or wrong, and may not even know that there's a right way of doing it at all.

The dead hand of the engineer who doesn't care is all over the British road numbering system. Let's see where it has struck.

The accidental motorway

We will begin with what seems to be a genuine mistake, and maybe even a well-intentioned one. If you've read our Ringways pages you'll know that, in the 1960s and 70s, there were grand plans for an urban motorway network criss-crossing London. A few odd little bits of motorway were built but mostly the plans are unrealised.

One little stub that did get built is called the West Cross Route, which links Shepherd's Bush to the A40 but was supposed to be part of something much bigger. It's been extensively rebuilt, but when first opened was a broad dual three-lane motorway with hard shoulders that ran for about a mile between two roundabouts. Until it was downgraded to an A-road in the late 1990s, it held the fantastically grand number M41.

We're talking about numbering mistakes, but M41 was quite a good fit: it was in motorway zone 4, and the number wasn't used elsewhere, so was technically valid. The mistake was that it was supposed to be called M14.

The M41 West Cross Route shortly before opening to traffic. It never gained its intended number, M14. Click to enlarge
The M41 West Cross Route shortly before opening to traffic. It never gained its intended number, M14. Click to enlarge

An internal memorandum between civil servants at the Department of the Environment in 1972, discussing potential motorway numbers south east of Birmingham, where you might expect to find a number like M41, explained the problem with this number:

“I should explain that we have problems with the number M.41 because at a very early stage it became attached to the West Cross Route in London. Eventually this will be sorted out and the allotted number, M.14, will be introduced. But this is unlikely to be done quickly because GLC are heavily involved with public enquiries and a change in numbers would be most unwelcome at the present time.”

The phrase "became attached" sounds almost delightfully accidental. It's easy to see what happened: it was meant to be M14, but at some point the digits were accidentally transposed, and since M41 appeared to fit nicely in West London, surrounded by 4-zone numbers, nobody thought anything of it until it was too late.

In 1973 it became clear that the rest of the West Cross Route would never be built, and the jumbled number remained in service until the stump of road lost motorway status about 26 years later.

Saved by roadgeeks

Here’s a very different kind of mistake. In the summer of 2011, Birmingham City Council opened a long-awaited bypass for Selly Oak, diverting the A38 away from the main shopping street. The old road, vacated by through traffic, was downgraded to a B-road. It needed a new number.

Its new number was B38.

The B38 in Selly Oak, 2011. Click to enlarge
The B38 in Selly Oak, 2011. Click to enlarge

In other UK territories that might be acceptable, but on mainland Great Britain, B-roads can only have three- or four-digit numbers. It was unprecedented.

Needless to say, the UK’s community of road enthusiasts, SABRE, were incensed. More than one sent messages to Birmingham City Council’s highways department, including one particularly bold, brilliant and self-effacing hero who later went on to write this blog post. The council confirmed that B38 was the chosen number, and that it had been agreed back in 2002 with the Department for Transport.

The next stop, of course, was to ask the same question to the DfT: was a two-digit B-road now permissible? Did Whitehall approve of this break with tradition? The reply did not share Birmingham’s positivity.

“You are quite right that B38 is a non-standard number, and does not match normal practice in road numbering. We are aware of the issue, and are in discussions with the local council to correct this.”

The discussions went on behind closed doors, but the outcome was soon made public. In April 2012, road signs in Selly Oak had patches applied, amending the road number to B384.

Bristol Road in Selly Oak does still have an incorrect number - being entirely in zone 4, it should have “4” as its first digit, and there were no shortage of suitable options available even if Birmingham were insistent that “38” had to appear somewhere. B438, for example, has never been allocated, so it could have been used. But at least the most glaring anomaly had been fixed, and B-roads were once again restricted to three- and four-digits. Order was restored.
For a few years, anyway.

The Maybole disaster

Just short of ten years after the B38 was consigned to history, Transport Scotland opened the new A77 Maybole Bypass in Ayrshire. It takes long distance traffic around the town of Maybole, providing welcome relief for its residents who, for decades, had suffered the noise and nuisance of trunk road traffic thundering by.

The A77 now follows the bypass. The old road, vacated by through traffic, was downgraded to a B-road. It needed a new number.

Its new number is B77.

Maybole's narrow high street, now relieved of through traffic and part of the B77. Click to enlarge
Maybole's narrow high street, now relieved of through traffic and part of the B77. Click to enlarge

Once again, the vigilant members of SABRE swung into righteous action, composing messages to Scotland’s trunk road authority to ask whether this was some terrible mistake. This time, though, the authorities were not to be swayed. Scotland no longer cares about the century-old rules.

“It should be noted that road signage is a devolved matter, and there is nothing to prevent a B-class road being given a two digit classification in Scotland. This matter has been reviewed by both the Ayrshire Roads Alliance and Transport Scotland, and neither organisation has found any issue with the chosen numbering of the B77.”

That is true: road numbering and signage are devolved matters, so Scotland is not beholden to Westminster, or anyone else, when it chooses numbers for its roads. They could have called the old road through Maybole the X5000 if they wanted, or Highway Z, or Route Four Billion, and nobody can tell them not to.

However, this is the first time that Scotland has actually done anything other than follow the rules established for the whole of Great Britain a century ago. (A pedant might also note that, while Scotland has the power to make its own numbering policy, it has never actually done so, and as far as anyone can tell its current policy is unchanged from the one it inherited in the 1990s, which permits only three- and four-digit B-road numbers.)

The A77 and B77 near Maybole. Click to enlarge
The A77 and B77 near Maybole. Click to enlarge

You could argue, of course, that it doesn’t matter; the old road through Maybole has a number, and few people will pay much attention to it no matter what it is. Call it B77, or B770, or B7700, or B7777 (all of which are available for use), and life will go on. Well, yes, of course it will.

But the point of the exercise was to move through traffic to the new bypass - to encourage it to follow a different path, where the road now divides, and take an unfamiliar route around the west of Maybole rather than the familiar way through the middle. The point was to make it clear that the A77 is now over here, and this road you used to go down is now something else.

If that is the object of the exercise, then why give the old road precisely the same number as the new one? Why not call it something completely different so that motorists approaching the critical decision point see only one road with the number 77? Why link the option you wish to discourage so closely to its former designation that it is distinguished not by its number, not by the length of its number, but only by its prefix?

That might be what’s so galling about the now-permanent B77. It’s the self-defeating thoughtlessness of it. If you’re going to have road numbers at all, then you should put at least a moment’s thought into what they are there for and what your choice of number will achieve. This one seems to defy its own purpose.

And so from one double-digit road in Scotland to another.

Snatching defeat from the jaws of victory

The B77 in Maybole is an example of a minor road that risks sounding too important. Scotland has an own goal of precisely the opposite kind as well: a major road that needlessly sounds unimportant.

Travel across the central belt between Glasgow and Fife, and your journey will probably include the M876, a motorway with a long and cumbersome number that is a victim of the Scottish requirement for all motorways to adopt their number from the A-road they replace. The A876 was the motorway’s predecessor, so its successor must be M876 even though all the numbers M81 to M89 are unused.

M80 and... M876? Surely a better number was possible. Click to enlarge
M80 and... M876? Surely a better number was possible. Click to enlarge

However, in early 1980, the final section of M876 opened to traffic, bypassing the old A876 through North Broomage and Antonshill. As is common, the old road was renumbered to remove the association with the number 876 and encourage through traffic onto the new motorway. But instead of a demotion, for reasons known only to themselves, Scottish highway engineers gave the bypassed length the unused number A88.

The result is that the old road, trundling through the towns of Stirlingshire, has the important-sounding and catchy number A88, while the high speed trunk road just to the north is lumbered with M876.

Why not just renumber the whole road to A88, which would permit this vital link in Scotland’s motorway system to be called M88?

No logical reason for this decision has ever been found, no official explanation has turned up to explain it, and nor does the open goal of M88 ever seem to have been considered. But then, if you go looking for logic in British road numbering, you’ll quickly find there’s none in sight.

A88, supposedly a downgrade from A876. What were they thinking? Click to enlarge
A88, supposedly a downgrade from A876. What were they thinking? Click to enlarge

Mistakes happen, of course, and the world muddles on regardless whether Britain has short lengths of road numbered B77 or B38 or M14 or M88. But all too often numbering is treated as an irrelevance or an afterthought, even by the professionals who are tasked with upholding it.

If we’re going to use road numbers at all - and we evidently are - then we ought to credit them with at least a passing appreciation of the value they can bring.

Road numbers have now been part of all of our lives for 101 years: a part of our national furniture without which we’d see the world, and our journeys through it, very differently. Road numbers are clearly worth the trouble. So, perhaps, we ought to go to the trouble of sparing them a moment’s thought when we need to come up with a new one.


John (UK roads… 4 May 2024

I do find it absolutely pointless that the A876 was renumbered to an important sounding A88 and do wish that the M876 has the '6' dropped making it a much better sounding M87 as it's easier to patch over, I still don't get why the Scottish government had to muck about with the renumbering up north removing the M85 though, Scotland basically acts as it's own country and will of course not follow the UK rulebook on anything including road numbering, I also wonder what the rules are for road numbers in Northern Ireland. It's also funny that that B38 briefly appeared but most unusual that it was fixed. Awesome article!

It is worth remembering that the Scottish motorway numbering system is different from E&W (motorways are numbered by the A road they replace or complement, and therefore use the existing zonal system as for other roads). So M87 is effectively reserved for a never-to-built motorway between Invergarry and the north of Skye, via Eileen Donan castle. The suggestion of renaming the whole length of the road as A88 makes the most sense, and would be a good fit for its near neighbour, the A89.

Yes but Scotland *is* its own country and it *does* have its own rules, when it comes to highways. I don't see how we can expect them to follow the rules someone in Westminster created years ago, when they're not even being followed properly by English engineers. That just strikes me as typical English exceptionalism.

Scotland is not a country, merely a region of the United Kingdom.

No, it’s a country. The word “country” doesn’t mean “sovereign nation state”. Wikipedia has a good definition as a starting point:

“A country is a distinct part of the world, such as a state, nation, or other political entity. When referring to a specific polity, the term "country" may refer to a sovereign state, states with limited recognition, constituent country, or a dependent territory.”

Anonymous 8 May 2024

This is a bit random, but I remember being intrigued by a "B50" I saw in the Philip's Street Atlas of Edinburgh. Unfortunately it was a misprint for the entirely unremarkable B1350.

Where is the line where geekery crosses into becoming a killjoy?
Britain has famously always been a nation of eccentrics - quirks, oddities and one-offs are all part of our charm. Getting all hot under the collar because there are a few harmless idiosyncrasies, feeling outraged (however slight and knowing!) that B38 should be the B38x or the B438 or whatever to slavishly comply with The Official Rule Book just means there are less fun oddities to look out for to relieve the tedium of a car journey. Boo!
All power to the A77/B77 - the next time I'm down that way I will be sure to toast it with a glass of non-alcoholic something. Vive la différence!

I agree. I'd add that a system is only useful when the vast majority of users can understand and benefit from it. The road number system (as distinct from the road numbers themselves (and i will reference this caveat when you keyboard warriors launch into one)) are not understood or used by most. The only real requirements for road numbers these days is to be unique and on google maps(other map apps are available).

Perhaps the solution lies in the example of the renumbering of the bypassed sections A74 to B70xx in various places, potentially incorporating the original number in the new number?

Anonymous 9 May 2024

So we have the M77, A77 and B77... is that unique on the UK mainland?

It’s definitely unique for a two-digit number, but there are - for example - an M876, A876 and B876. There will probably be others matching the numbers of three-digit motorways. 

If you count M6 Toll as its administrative number of M600, A600 and B600 also exist

The former A601(M) comes to mind instantly when it comes to random and inconsistent road numbering!

Bryn Buck 11 May 2024

101 years since introduction it's surely time for a wholesale review in light of advances in navigation and the arrival of motorways.

The current system is no longer fit for purpose, it just isn't.

There is another post on the subject of road numbering on this site. I raised on it the case of the M62 (it should of course start with a 5) and also the A66. And with regards to Scotland the saga of the M6. Most of you will remember that during the upgrade of the A74 signs stated that it was to be called the M6, but its never happened and will never happen.
And about 30 years ago the saga of road numbering was raised in the Daily Telegraph motoring section one Saturday. Some from the the DOT said that road numbering "was being looked at". In the civil service if something is being looked at that means theyve lost the file!

I would suggest that the country has considerably higher priorities to spend a gazillion pounds on than this, what with consultants fees, patching tens of thousands of signs and a lengthy public information campaign because the government will be beside itself with worry that Outraged of FacegramtokX might be confused by changing it.
Auntie Google Maps says look for A999, Joe Bloggs looks for sign with A999 on it. Sorted. The fact that the geeks and experts say that, in an ideal world, it *should* be the Q6793 is irrelevant.

As for spending money, Blair said that it would cost at least 700 million quid to change the roads signs to metric so they werent going to be changed while he was Prime Minister.

Andrew Cameron… 17 May 2024

So, how long before the Scottish government take back control of the A1 and renumber that road (and other A1* roads) north of the border.

I have suggested this on another post. To me it seems odd the the M6 stops before the border but the A1 keeps merrily rolling along to Edinburgh.

I was told that was because the original zones were based on an A road running from major centre to major centre, so the A1 was London to Edinburgh, A2 London to Dover, A3 London to Portsmouth, A4 London to Bath, A5 London to Holyhead, A6 London to Carlisle, A7 Edinburgh to Carlisle, A8 Edinburgh to Glasgow, and A9 Edinburgh to Inverness. As I understand, it was decided that the M6 couldn't, therefore, run to Glasgow because Glasgow is the '8 zone' and the space between it and Carlisle is the '7 zone'.

Thats a very good point about the M6, but why do the Scottish government not come out and say that its because of that the A and M 74 havent been renumbered? Dont forget that the plan 30 years ago was for the M6 to run all the way to Glasgow.

Except that the A-road zones are irrelevant to motorway numbering. In England and Wales they have their own zones, which are independent of A-road zones, and in Scotland motorways simply take the number of the A road they are intended to replace.

Regardless, in both cases they are just an overall system and, by accident or design, exceptions exist (indeed, that's the entire point of this article!) so if they wanted M6 to run to Glasgow there's nothing stopping them. Personally, I suspect its more likely a case of not wanting an "English" motorway number in Scotland.

JazzDad 22 May 2024

And certainly, DO NOT come to the USA looking for any rhyme or reason to the roadway numbering system. The interstate highways USED to have a set of guidelines, but those seem to have devolved, also. When you have all the fingers of federal, state, county, municipalities (cities, towns, villages, etc) sticking their possessive fingers in the pie, the pie will be a mess.

There still is a certain amount of rhyme and reason to the number grids of the US for Interstates and US Highways. Most do follow the numbering conventions of the grids, though while one could argue that the duplicates shouldn't exist, I don't think the average driver's gonna care that there are technically two I-42s, I-74s, or I-87s. In fact, I doubt most would care too much about it, given that each state is allowed to use all nine 3dis for each 2di they have, regardless of whether or not any particular 3di is already in use in another state.

And one could very well argue that the grid was broken as soon as it was created back in 1926. US 11 runs a diagonal route from the Canadian border in far NE New York down southwest to New Orleans, LA, crossing US Routes 21, 31, and 41, with only US Route 51 being separated from it by the city of New Orleans itself. What wound-up becoming the famous (US) Route 66 was originally intended to be US Route 60 prior to some of the eastern states complaining about the lack of a major US Route. Due to getting a new alignment, the resulting US 66 wound-up being entirely north of US 60, and thus entirely out of grid.

And of course Canada changes road numbers at the boundary of each Province. For example route 401 in Ontario becomes autoroute something else in Quebec. I think the only road in Canada to keep its number is the Trans Canada Highway.

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