FAQs about the transition to metric signs on UK roads

Readers have commented recently on the obstacles to the transition to metric-only signs on Britain’s roads. This has prompted Metric Views to offer answers to some Frequently Asked Questions on this subject.

In 2006, the UK Metric Association (UKMA) produced a report ‘Metric signs ahead’. This advocated the change of UK’s road signs to metric, provided an estimate of the cost, and looked at the way the task had been tackled successfully in a number of Commonwealth countries and in the Republic of Ireland. The report produced a bewildered response from the Prime Minister, a dismissive reply from the Secretary of State for Transport, and a grossly-inflated cost estimate from his civil servants. Since then, events have followed a predictable course. In particular, the Traffic Signs Policy Review, which was billed as the most radical shakeup of road traffic signs for over forty years, failed to consider the radical option of metric-only signs, and then lost impetus. The Traffic Signs (Amendment)(No 2) Regulations and General Directions 2011, which originally promised savings from dual (imperial and metric) height and width restriction signs, also seem unlikely to deliver.

In the absence of credible responses on key issues from official sources, Metric Views is happy to offer answers to some of the FAQs put by readers.

FAQ 1. When was it first proposed that the UK’s road signs should be changed to metric?

Metrication of road signs was implicit in the original decision in 1965 that the UK should adopt the metric system as the primary and eventually the only measurement system for all official and legal purposes.  However, it was not until the late 1960s that firm plans were made – with a target date of 1973 for converting road signs.  However, following the change of government in 1970, the Minister for Transport Industries, John Peyton, postponed the target date, which has never been reinstated.

FAQ 2. Has a change on this scale been carried out successfully before on UK roads?

The system of British road signs was first developed around the turn of the twentieth century, but its most radical overhaul came between the Second World War and the Worboys Report of 1964. The final report of the Worboys Committee detailed a set of traffic signs that was an enormous improvement over its predecessor. It received widespread congratulations from the press, industry and motorists themselves. Britain, at last, conformed to European standards, and made full use of the technology then available to make large, detailed and colourful signs. Since then, the acclaimed system has been tweaked several times, but no need has ever been identified to change anything on a large scale, other than the system of measurement used. The full story can be found at: http://www.cbrd.co.uk/histories/wartoworboys/

FAQ 3. Would the costs involved for the UK in changing the measurements used on road signs, replacing signs, providing safety and publicity material and the consequential costs for businesses and other organisations exceed any benefits?

The costs are relatively easy to quantify (and inflate) and fall largely on government and the transport industry. The benefits are often less quantifiable, and involve the whole UK economy. An example is the problem of school leavers’ lack of familiarity with metric length and distance measures, particularly when entering the world of work.

On signage of height and width restrictions, a recent cost-benefit assessment showed that in England and Wales the one-off cost of the change to dual signage would be £527 000, whereas the benefits over a ten year period would be at least £2 335 000 – a net saving of £1.8 million. (Source: pages 2-3 and page 11 of Annex D to the DfT’s consultation document, http://ukma.org.uk/sites/default/files/rtc2011-12-annex-d.pdf)

FAQ 4. What is likely to be the cost of changing road signs for distance and speed from imperial to metric units?

The UK Department for Transport (DfT) prepared a report in November 2005 “Estimating the cost of conversion of road traffic signs to metric units”. (Source: The National Archives http://tinyurl.com/7bqczxa)

The estimates in the report gave an average cost of £1400 per road sign. This figure has regularly been called into question. For example, in 2009 in response to a parliamentary question, the Minister of Transport, Chris Mole, said “Driver Location Signs were introduced in 2003 and approximately 16 000 signs have been installed on 80% of the motorway network at a cost of £5.9 million. ….”. Thus, the average cost of driver location signs was £370 each. (Source: House of Commons Hansard http://tinyurl.com/6ohjtsp)

Last year, the Spanish government changed all their speed limits signs in a single day for €250 000, in order to promote fuel economy. They changed about 6000 signs by using vinyl overlays. This cost an average of €41 or about £35 per sign. (Source:http://www.bbc.co.uk/news/world-europe-12663092)

The estimate of the cost of  conversion to metric of speed and distance signs given in ’Metric signs ahead’ is in the range of £41 million to £160 million with a most likely cost of £80 million. This gives an average cost of £160 per sign, which is close to the actual cost of the change of speed limit signs in the Republic of Ireland in 2005.

FAQ 5. In this age of austerity, is there any room in the transport budget to pay the up-front cost of changing road traffic signs?

Few would claim that the transport budget is free of waste. For example, the House of Commons Transport Committee noted that £71 million had been spent on building 66 motorcyclist testing stations in order that learner motorcyclists could take the manoeuvring elements of the driving test at the requisite 50 km/h. This speed would be illegal on the quiet residential roads in urban areas where tests had previously been conducted, yet the Department had preferred to build the centres rather than seek a derogation of the requirement. (Source:http://www.publications.parliament.uk/pa/cm200910/cmselect/cmtran/442/442.pdf)

FAQ 6. It has been recognised for many years that there are benefits to the UK economy from having a single simple and widely understood measurement system used for all public purposes. Are there also benefits specifically for motorists from the transition to metric-only road signs?

The report ‘Metric signs ahead’ outlines a number of benefits for motorists from the transition. These include:

  • Consistent information
  • Compatibility with the Highway Code
  • Compatibility between vehicle manuals and road signage
  • Emergency incident location
  • Calculation of fuel consumption and engine efficiency
  • Sensitivity of speed limits
  • Cross border traffic, to and from the UK
  • Consistency with OS mapping

FAQ 7. Is there robust evidence to show that the metric changeover can be carried out without adversely affecting road safety?

There is evidence from abroad that the metric conversion of road traffic signs can be done safely. This was the experience in the 1970s in Canada, Australia, New Zealand, South Africa and in 2005 in the Republic of Ireland. More recently, Spain provided further evidence that speed limit signs can be changed safely.

FAQ 8. Can we learn from the experience of other countries?

Yes – but only if we don’t leave it too long, because officials in Commonwealth countries with experience of the changeover are likely now to have retired (and are certainly not immortal!).

FAQ 9. If the change to metric road signs is required by the EU, then should not the EU pay for it?

The EU directive relating to units of measurement permits indefinitely both metric units and the mile, yard, foot and inch on UK “road traffic signs, distance and speed measurement”. Clearly, this is a matter for the UK government. If it can be shown that the transition to metric-only road signs is in the UK national interest, then the UK should expect to pay for it, rather than other countries.

FAQ 10. Could the nations of the UK go their separate ways?

Although the directive mentioned in FAQ 9 permits metric or imperial road traffic signs for distance and speed, the implementation of this directive is a matter for the UK Government, and is not currently devolved.

FAQ 11. Is there any country in the world, other than the UK, where metric road traffic signs for distance and speed are banned?

Not as far as Metric Views is aware.

Readers may have their own questions on this contentious topic. Please pass them on to Metric Views and we will see if we can provide answers.

A copy of UKMA’s report ‘Metric signs ahead’ may be downloaded free at: http://www.ukma.org.uk/sites/default/files/MSA.pdf

45 thoughts on “FAQs about the transition to metric signs on UK roads”

  1. Re: FAQs 7 & 8
    40 years is a long time.

    In the US, the Federal government pushed for metrication while the States resisted. There are a small percentage of “exemplar” metric signs around the country, but no widespread use. Even in this mixed environment, there are no piles of dead bodies around the metric signs. The safety argument is greatly overblown. (USMA site has example photos including some obsolete signs with dual speed limits that would not be allowed under more recent editions of MUTCD. But signs that were legal when erected are generally “grandfathered.”)


  2. Re FAQ 9/10 above:

    Wales has for a long time been authorised to make Wales-only amendments to TSRGD for “purposes of language translation”. Nothing to do with any EU ruling on the subject, the Welsh Language Act requires that Welsh be regarded as equal with English in matters of public life in Wales.

    As a result you end up with some really cluttered signs in Wales!

    Now – this might be a matter for the UKMA’s legal eagles to go and take a look, but I’d say that if the Welsh Assembly’s Transport Department could be persuaded that a switch to kilometres on Welsh road signs would count as a “translation issue”, then they might well already be quite within their rights to switch Welsh roadsigns to metric and avoid a lot of this clutter. The signs would physically get smaller and would presumably be cheaper to make too.

    It would make sense for Wales to adopt the “two arrows on either side of the distance indicator” trick to indicate “hazard starts from here and lasts for the indicated distance” because current signs say things like “For 1½ miles/Am 1½ milltir” whereas they could just say “^2.4km^” (where ^ is supposed to be an up-arrow). “Am” is of course Welsh for “for”.

    Much smaller, less cluttered and understood by all. Including all those foreign visitors that Wales is keen to attract to its beauty spots and hotels.


  3. An important point on the costs; while there would need to be a rapid changeover for certain signs, which would come with a (modest) cost (and valid, but difficult to quantify, benefits), many signs could be changed at nil cost.
    It is scandalous that almost 20 years after the introduction of dual unit height signs, which the DfT itself says would reduce the number of bridge strikes which cost the economy a large amount each year, new imperial-only signs are being erected to this day with the endorsement of the DfT. Had the DfT simply required metric units to be added at that time, rather than made it optional, the nation’s low bridges would by now be signed in both units, foreign hauliers wouldn’t be causing as many accidents as they do, and we could by now be painlessly changing in-cab vehicle height notices to metres and phasing out imperial units. All at no cost.
    If this government means what it claims about investing in a more efficient economy, it should begin with metric road signs, but I’m not holding my breath.


  4. Regarding FAQ7: I can just imagine the headlines of such papers as the Daily Mail if the switch to km/h speed limits was ever announced. Probably huge letters, saying ‘CARNAGE!!’ or some such thing. Of course it simply isn’t true, as FAQ7 mentions. It is fortunate that a number of other countries have already made such a switch (Canada, Australia, South Africa, New Zealand, Ireland, to name but a few), and we can point to their ACTUAL real world evidence that such a switch had no negative impact on safety.

    I remember the conversion in Canada well. Saturday night – all the speed limit signs in mph. Sunday morning – everything in km/h. Many cars at that time (1977) had mph-only displays, yet we still coped. Other cars had km/h-only displays, having been on sale since the beginning of that year, and, prior to the switch, we still coped. Today almost all cars have dual displays (even if, as has been mentioned here before, and certainly in my own case, the secondary km/h display is all but illegible)

    The overnight switch to km/h had so little impact on safety that it was unmeasurable. IF there was any deterioration in accident rates due to confusion over the new speed limits, it was more than cancelled out by the better correlation of 10-km/h increments to prevailing road and traffic conditions. Police, for a while at least, were a bit more lenient in writing out speeding tickets, especially if you had an mph-only speedometer.

    In, I would say, less than two months, people had forgotten what the old mph figures looked like – everyone had adjusted (I remember a work colleague getting a ticket in November 1977, just two months after the switch, and, in bemoaning her misfortune, never once reverted to mph).

    Even more salient, the newspapers were notably completely silent on any safety concerns once it became obvious there weren’t any. It is a message that needs to be reinforced in very strong terms to counteract the use of this red herring by those who will oppose any idea of converting Britain’s road signs.


  5. There is conceivably a slight risk of some motorists driving too fast in say a signed 50 km/h speed limit zone not realising the sign did not mean 50 mph. But it is pretty unlikely given the publicity that is bound to precede the change. Anyone not aware would have no real excuse and serves them right if they are penalised.

    As for carnage, well such incidents would be comparativey rare and even then it would have to give rise to an accident before it counted as being a consequence of the change. I was not at all suprised that nothing was reported in the Irish press in 2005.


  6. Any reason for the UK not to adopt the Irish program of conversion of speed limit signs (and the distance signs that were still in Imperial) “lock, stock, and barrel”?

    They could use as an estimate the actual cost of the conversion in Ireland scaled up by the ratio of the number signs in the UK divided by the number of signs in Ireland.

    You wouldn’t even need a calculator to figure that one out! 🙂


  7. On 7 Feb, I wrote to the Department for Transport about this article. Here is the full text of my email to the DfT:


    I have recently written an article for Metric Views (http://metricviews.org.uk) on road signs and I hope that you will find this article informative. It was posted on the Metric Views website on 27 January 2012. You can find the article here:

    DfT staff and ministers are welcome to post comments on this web page in response to this article. Please join the debate and add your own comments.

    I have also written an 80-page booklet called “Made in Britain: Not made to measure”, which is published by the UK Metric Association. It is publicly available as a FREE download. You can find it at http://www.ukma.org.uk/articles/rcohen. This booklet includes a section called “What is Wrong with Two Measurement Systems?”. That section includes a subsection called “Odd Use of Measurement Units by the DfT”.

    I hope that you will read this article and my booklet with an open mind, even if you disagree with them. I hope that you will find them helpful in developing future policies.

    Did you know that:
    The UK is the only country in the world that bans the metric system for speed and distance signs?
    The UK is the only country in the world that uses yards on its roads?
    The UK is the only country in the developed world that bans the metric system from almost all of its road signs?
    The DfT is out of step with the modern world in its use of imperial units on UK roads (out of step with private industry, other government departments, Europe, the Commonwealth, the developed world and the UK education system)?

    This is all a consequence of DfT policies. How eccentric!

    With kind regards,
    Ronnie Cohen”

    On 21 Feb, I received the following response from the DfT (Reference: GT 51/3/3/31768):

    “Dear Ronnie Cohen,

    Metric views on road signs

    Thank you for your e-mail of 7 February 2012 about traffic signs.

    We receive many letters asking why we do not use metric measurement on traffic signs from members of the public who feel that the imperial units are now outdated. But we also have people who write to us as they do not want to see metric units on signs and request that we do not change them.

    This subject has been discussed in the European Parliament at length and they held a public consultation on amending the Units of Measurement Directive. This government asked for permission to continue to use imperial measurement (one reason being the enormous amount of money that it would cost to change) and the outcome was that this was agreed.

    This Department worked out that the overall cost of changing traffic signs would be over £680 million; there is information on how this value was worked out on our website at “Estimating the cost of conversion of road traffic signs to metric units” and we do not consider that we can take money away from other more important areas of work to do this.

    Thank you for taking the time to write and I hope that my answer has clarified the position.

    Yours sincerely,
    Ashraf Keeka”

    I wonder how much attention they paid to FAQ 4 in this article, which was about the DfT’s cost estimates for the metric conversion of road signs. Judging by their response, they ignored it and still refuse to acknowledge that their cost estimates are grossly inflated despite all our evidence to the contrary. I tried to encourage DfT staff and ministers to post comments here in response to this article but they were not interested in doing so. This is unsurprising as they are not interested in having an open debate about measurement units on road signs. Their ridiculous estimate of £1400 per sign for the metrication of road signs seems to be a deliberate attempt to stifle debate about the metrication of road signs.

    I informed the DfT about a section in my “Made in Britain: Not made to measure” booklet, which explains how the DfT illogically uses yards for metres and the random mix-and-match approach to measurement units in the Highway Code. Everything I have said about the DfT in this article and in my booklet had no impact on the DfT and they just do not care and will not listen to anyone. We saw that in their irrational, inexplicable and incomprehensible response to their consultation about mandatory dual signs for bridges, despite their own cost estimates of a net saving of £1.8 million over ten years and strong support for the change from many stakeholders.

    Interestingly, they did not dispute what I have said about the DfT except what I have said about their cost estimates. The main problem with the DfT report is that it is not based on any actual costs but is based on a whole series of dubious and wild assumptions about the cost of road signs.


  8. Perhaps what might help is to provide DfT with the detailed cost estimates from UKMA for road sign conversion and ask them to comment.

    Or is there an MP who can (and would) raise the question of the accuracy of the DfT cost estimates for sign conversion to get a detailed response from them?


  9. One more thought: might there be a private UK firm that is well respected that would be willing (pro bono, of course 🙂 to vet the numbers that DfT are using for the sign conversion project? That could shoot big holes in their inflated numbers.


  10. Perhaps Ashraf Keeka at the DfT can explain why his boss did not require dual height and width restrictions, which would have then provided money for “other more important areas of work” whatever these may be.


  11. With reference to the statement “Last year, the Spanish government changed all their speed limits signs in a single day for €250 000, in order to promote fuel economy. They changed about 6000 signs by using vinyl overlays. This cost an average of €41 or about £35 per sign. “; this comparison is so wrong on every level. Speed limit signs can easily be changed in the UK. Put a new sticker over the existing sign. The real costs involved moving gantry signs and all signs that have distances on them. These have to be moved or manufactured to reflect the correct distances. A sign with 2 miles on it cannot overnight change to read 2 kms. What next? Allow 24 hour clock times on parking signs?


  12. @Mark Swain: you state that distance signs would all need to be remade and gantry signs moved.

    Firstly, consider the state of many of our road signs – they clearly have adhesive letters applied, as you can see them peeling off! It would therefore be a case of removing the old digits, and replacing them with the amended km distance.

    Regarding gantry signs – I am not quite clear what you mean, but if you refer to signs on overhead gantries that are positioned a mile and half mile before a junction, then I think that all is need is a 1600 metres and 800 metre sign respectively to be attached in replacement. Motorists on major routes would also have have the blue and white reference markets that currently exist and are placed 100 metres apart. Other signs that warn of hazards such as traffic lights currently may refer to ‘110 yds’ or other distance is yards. I think you will find that many signs were located with a possible metric conversion in mind, e.g. 110 yds is 100 metres.

    The fact is that Britain needs to make the change to metric. The recent survey reference numeracy shows that the kids and adults alike need things to be as simple as possible, and metric offers that ease and familiarity.


  13. Mark Swain: there’s no need to physically move gantries. There would be a need to do a bit of vinyl overlay work on the signs on the gantries, and if you notice you’ll see that on newer roads there seems to be a tendency to flag upcoming junctions with “? m” and “? m” signs – obviously making those gantries conveniently able to carry “1 km” and “500m” signs in the future.

    But gantries carrying signs saying “2 miles” as you mention, these would just end up bearing signs saying “3 km” in future. No-one’s going to move the bl**dy gantry! It would cost a fortune, so should be left until the road needed a redesign. Look at the M4 around the north of Cardiff in South Wales. Used to have gantries advertising upcoming junctions in mile and half mile intervals. Then they did a 5-year long rebuild of the road to widen it to 3 lanes both ways, and now all the (repositioned) gantries have “? m” and “? m” signs.

    Bear in mind that existing signs are only accurate to the nearest permissible mileage (or yardage). Permissible (short) mileages are 1 mi, ¾ mi, ? mi, ½ mi, ? mi and ¼ mi. On “K day” they’d probably just blanket authorise these to be replaced with 1500 m (or 1.5 km), 1200 m, 1000 m(or 1 km), 800 m, 500 m and 400 m signs respectively without expecting the local authorities to re-measure or reposition anything unless they wanted to do so.

    Sure, the one mile signs would be more accurately replaced with 1600 m signs, but 1500 m is already a well understood distance in international athletics so I’d recommend plumping for that rather than being picky. It’s likely to be within about 10% of correct anyway, which is all the existing signs ever achieve.


  14. Mark (again). “Wilfred” above has a valid point (depending on how you read his comment!). After spending trillions of pounds of taxpayers’ money on designing a new dual-units warning triangle for bridges, the DfT have chickened out of either requiring old imperial-only signs to be replaced using the new sign, or requiring the new sign even to be used in a new installation. It is perfectly possible for a Luddite authority to signpost a brand new height restriction situation in imperial only.

    I thought this was what Wilfred was saying.

    I think I can sympathise with the idea that in the current financial situation, old height limits could stay as they are (even imperial-only ones) until they needed replacing. But at replacement time, imperial-only should no longer be an option. It’s a disgrace that in the 21st century with all the signs for dual-signage designed and on the statute book, that they not be mandated for new installations.

    The DfT are pasting themselves into an untenable corner. Every petrol station canopy in the UK now has height clearance signs in metric, and most are metric only. Round here (South Wales) pretty much all the council-owned off-road signage for height restrictions is in metric-only, same with the hospital trusts. The road signs are looking more and more like they belong in some theme park with every day that passes. Maybe the UKMA could lean on the railway authorities to lean on the DfT to fix this “oversight” in TSRGD 2011 where the imperial only signs didn’t get deprecated. TRSGD 2012 anyone?


  15. Mark: Your assessment in determining what needs to be changed is wrong on a couple of counts. When I lived in Canada in the 1970s and witnessed first hand how Canada did it (I even served on a conversion committee briefly), very little got changed, at least initially, in things like moving gantry signs and other major works. A level of inaccuracy was tolerated in terms of distance. In general, most distances were rounded to the nearest kilometre, so that 2 miles became 3 km (exact conversion: 3.2 km), and 1 mile became 2 km (exactly 1.6 km). Likewise for all other distances shown on signs; the signs were not moved, simply a rounded distance shown (and initially a small ‘km’ plate added above the sign if there was not room to add the ‘km’ after the number).

    The only exception to that rule was for distances less than 1 km. Then the distance was shown in metres rounded to the nearest 100 m. Half a mile did become 800 m. If there was no probability that the sign would be moved due to road works, etc, then eventually the sign would be moved to an even 1 km. Otherwise the 800 m would stay until road works/sign replacement would enable a rounded ‘km’ distance to be obtained.

    Even freeway (motorway) exit signs were rounded, so that the first exit sign said 2 km (even if it was something different), while the second was marked at 1 km. A few got marked in metres (to the nearest 100 m) where there were two or more exits in close proximity to each other. We seemed to cope with the inaccuracies with few problems – few cars back then of course had odometers that showed km (as is the case in the UK today). Over the course of time, most signs did get moved to a more accurate location, but it was not a priority or considered to be a matter of urgency.

    And yes, some provinces (notably Alberta) did change all the parking restriction and other time-related signs to 24 h format.


  16. Mark – explain why gantry signs need to be moved and why “2 miles” signs have to be changed to “2 km”… or why it has to be done overnight.

    First of all if you’re going to sticker over “2 miles” you’d likely use “3 km” and, unlike some seem to think, you wouldn’t quibble over the .21… just remember that current rules allow for a percentage of error in the distance. No need to move signs or gantries whatsoever. And you wouldn’t have to do it overnight either, most other countries who have converted did distances over a longer period, it’s only speeds that need to be done overnight.

    Coming back to gantries for a moment though, it is true that many electronic gantry signs can only display 2 digits due to the way they were designed and replacing those will cost money – however the blame for that lies clearly at the door of the DfT for not planning ahead and specifying equipment that was capable of handling km as well as miles.


  17. On reading Mark’s comment my reaction was much the same as those of other contributors. The positioning of distance signs is determined by physical requirements and practicability not the units used to express it. That is why the range of uncertainty is relatively large.

    I would simply add that as the km is smaller than the mile it is likely to be more accurate. Also the metric alternative does not need fractions and is more flexible for shorter distances. The relationship between the metre and kilometre is much easier than that of the yard and mile, so whole numbers can always be used.


  18. As a bit of an aside, does anyone know why the TRSGD specifies a combined metric/Imperial height restriction sign but two separate length restriction signs (one Imperial-only and one metric-only)? Has anyone seen the metric version on the roads? What are the rules for using one or the other?


  19. @Ezra
    Restriction signs are round so there is enough space to fit in two measurement units on the same sign. The length restriction signs you are referring to are triangular so there is not enough space to fit in two measurement units on the same sign unless the sign is made bigger. Hence roundels are dual but, until the current change to the TSRGD, there had to be two separate triangular signs to display a metric sign. I have heard that larger dual-signed triangular restriction signs are now permitted. A metric-only triangular restriction sign can be used as long as it is accompanied by an imperial-only triangular restriction sign to the left of or above the metric-only triangular restriction sign.


  20. @Ezra

    This is obviously just an opinion. On height and width, the metric fits with only minor rearrangement of the elements of the sign. The layout of the length restriction sign doesn’t allow room without radically reducing the font height of the numbers (or using a larger diamter sign)

    They would have to approve some other sign style, such as allowing a metric placard with the limit underneath or a rectangular sign with the round image and Imperial limit, and the metric limit as supplemental info underneath. More radical, perhaps the vehicle could be shown in plan (overhead) view with dimensional arrows in the left 1/3 of the sign, and leave room in the right 2/3 for both Imperial and metric length restriction. In any case, it would require a new sign type to fit the information. Since US regulatory signs are rectangular, we wouldn’t have the same issue (we just have 50 States who don’t want to use metric).

    I think in all cases, they require the Imperial and allow the metric as optional. That needs to change first. As long as they treat the metric as not really important, it won’t be used much.


  21. Ezra asks “Has anyone seen the metric version on the roads?”

    There are two 9 m length restriction signs at the start of a single track road around half an hour north of me (which I drove by today). They have been there for a good while – since March 2009 at least.

    There are no imperial length restriction signs anywhere in sight. However, there is another sign beside one of the “9 m” signs stating “Weak Bridge 4 miles ahead” with a “17 T” (capitalised) weight restriction.

    Just the usual confusion, then!

    I would provide a link to Google street view, but am worried that some BWMA sad act would waste my council tax by making a needless complaint to the local Roads Department.


  22. Hi everyone:
    I do not know how signs are placed in the UK. However, in the States we have some Informational signs where distance is placed in two columns, examples found at US Metric Association, http://lamar.colostate.edu/ miles next to kilometers. The other distance signs near the road side in miles would have to be replaced with signs in meters before an exit in a different location to be of use to drivers. The regulatory speed sings, that were put in storage, for lack of budget or interest had km/h underneath MPH.


  23. @Ed the Yank

    A long time ago, there were some speed signs in the US with both MPH and km/h. However, they were deemed confusing. The MUTCD was changed so speed limits HAD to be a multiple of 5 MPH or 10 km/h. That requirement insured no new dual speed signs. (The MUTCD generally grandfathers signs that were legal when erected.)


  24. @Ronnie
    I’ve just checked the UK Road Signs Manual and the length restriction sign is circular, not triangular. You can see a metric version here

    To be honest I can’t see any easy way to put both units on this sign without removing the vehicle pictogram.


  25. Hmm – just out of interest (regardless of the choice of units for once) does a sign like the one in Alex Bailey’s link (above) prohibit only *trucks* of the given length? If you want to prohibit buses of that length, do you need another sign with a bus icon?

    Strikes me that they should have designed it as a roundel with just a truck *and* a bus icons, leaving the max length info for a supplementary plate beneath (in dual units presumably).


  26. Perhaps all dual length, height, and width restrictions should use a secondary plate. Make a proper metric sign, and mount a supplemental imperial plate under it. Make sure the imperial plate wears faster; when it wears out, people had better have learned metric. 🙂


  27. Just a small sign (pardon the pun) of progress, but if you check out the web site that Alex Bailey pointed out and look at their full page of UK road signs here:


    you’ll see that the two signs that could have been shown in either Imperial or metric (height restriction and length restriction) show only the metric version. (Look at about 1/3 down the page and again at about 2/3 down the page for these signs.)

    From everything I hear the UK really is at a tipping point for metrication. Converting road signs and getting the BBC (at least) to stick with metric would be just the push the country needs to rapidly shed most vestiges of Imperial within a few short years.

    Ah, well …. maybe when Labour is in charge once again. Maybe!


  28. As a starter, all the signs in yards (god, what are they! says a kiwi) could be switched to meters by sticking a striker with “Meters” on it over “Yards” – they’re basically the same and would acclimatise the public.


  29. I know that metric signs have been used for several years, notably ‘Location Signs’, and the 100 m markers on the M roads and some of the A roads in this country. I’m not sure how easy it would be to convert the Variable Speed Limit signage to metric, but presumably only for the software itself; the digital displays on various motorways would be identical, physically.

    The other oddity is the continued use of the old-fashioned fuel consumption, in ‘mpg’, even though fuel has not been sold in gallons in the UK for three or more decades.

    In my own modern car (which is a Honda Civic, with digital speed display, not analogue), and I always run it in metric mode, with it’s speed display in km/h, and fuel burn in L/100 km; I prefer it that way, even in England!


  30. Just wait till the US decides to go metric and watch the lapdog UK government follow suit! Pathetic. This mess perpetuates lack of mutual comprehension, deficient numeracy skills and those who understand some units, both, all and fewer!


  31. @John Keepin,

    The problem with digital variable speed limit signs is apparently they only display to two places, thus are virtually useless for use in km/h.
    This was either a serious oversight, an excessive cost cutting exercise, or deliberate blocking of metric by DfT. I would go for the cost cutting with a bit of metric blocking for extra measure.


  32. @Americans for CW&M:

    You seem proud of the fact that the USA is stuck in the past. Considering that the America USED to be the most forward looking nation on the planet, that is very sad. Much of the world now sees through the American façade of being an advanced nation. Go to many parts of the world (especially in S E Asia and the Australian continent), and you will find no-one who understands imperial/’customary’ weights and measures, and thus will not do business with the US. Why you would be proud of that seems very strange.

    What has America got to actually lose by completing its conversion to SI? The only downside is some inconvenience and a little extra hard work in the short term. If that is too much of an effort for Americans, then maybe the country deserves to lose out in trading with the rest of the world.


  33. I have to agree with John Frewen-Lord. Despite the fiction one encounters in the US press, the American economy is very weak and industries are under-performing. Most that do make things are in a muddle. Every product produced is a hybrid with a mixture of USC and metric parts. This adds costs as mistakes are on the increase as metric and inch made parts don’t fit well together. You are never sure what tool to use for assembly and service as there will always be a mixture. Chinese inch made fasteners for the US market will more often then not need a metric tool as the head is metric even if the threads are inch.

    The German economy continues to boom while the US economy continues to dwindle. For the world it is good that the US may be demetricating. It is a better reason not to buy American products. Hard work is no longer in the American vocabulary. Quick profit with no effort is the mantra of the day.

    Everyone knows that America’s days are numbered. China is now selling all of its US debt and others are following China’s lead. Everyone sees that the US wanting to be different is not in their best interest and in a few short years a bankrupt and impoverished USA will be wishing they would have gone metric went hey had the chance.


  34. I would be curious to know what measurement changes are resulting in demetrication.

    Is ACWM referring to one Listerine Total Care product in a 946 mL size?

    Listerine Mouthwashes are still available in 1 L and 1.5 L sizes, as are their clones.

    It should be noted that there is a push in the US medical industry to get rid of pounds and dosing in teaspoons. Millilitre dosing is now appearing on most new over the counter products. And the US automotive industry is not de-metricating.


  35. There is absolutely no good or logical reason for road signs in the UK to be changed to metric! It’s just another example of pointless interference from the EU, seeking to impose unnecessary and expensive job creation schemes for no practical benefit. Everyone in this country, understands miles & yards and if they don’t; learn to!
    Such expense would be far better employed maintaining the road signs and markings that we already have. There are now so many road markings that are practically non existent, creating major safety concerns. Also, there are many locations across the country where road signs are obscured by trees and hedgerows etc.
    Lets invest some money in looking after what we have, rather than pointless change for changes sake.


  36. @ Lee

    “Everyone in this country, understands miles & yards and if they don’t; learn to!”

    Do they or is that your fantasy wish? It is time people like you learn metric (you already do and just pretend you don’t) and use it, not the other way around.


  37. @ Lee Price says: 2016-11-02 at 11:48
    “Everyone in this country, understands miles & yards and if they don’t; learn to!”

    Really? I am in my 70’s and yes I know how many yards in a mile, so what? How do I work out multiples of 1/10 th’s of miles whilst driving? Now you personally may be a mathematical genius and a master mind of mental arithmetic, great for you, but don’t expect the rest of us to be as brilliant as your good self.
    It is metric all the way for me and I personally can’t forget that b awful non-system soon enough. Metric (SI) is a world wide system and it looks like it is here to stay. So, learn it, if you haven’t already, join the 20th century and work on joining the 21st century sometime.


  38. #Lee
    A big problem with U.K. road signs is the mix of metric and imperial measurements, the latest Highway Code contains many metric references to fit in with the UK education system yet few are allowed on UK road signs.
    The Gibraltar Highway Code looks to be a straight copy of the U.K. Version with changes to driving on the right and nearly all metric, apart from that It’s what the UK system should be like.


  39. @Lee Price:

    There are loads of `good or logical’ reasons, whose validity you seemingly aren’t prepared to entertain. There are none so blind as those who shall not see. In any case, UK signed the Vienna Convention in 1968—long before joining the EU. So you’ll need another referendum, at least two new prime ministers, etc. if you want to withdraw from yet another treaty. If EU were that good at `interference’, all other member states would have road signs and markings (and roads themselves) designed, constructed and maintained as poorly as ours and/ or they’d be paying similarly high taxes for the privilege. But this is not the case. Go and have a look for yourself: you might be surprised/ perplexed!

    The risk with relying so heavily on the cost argument is that someone will eventually propose a way to do it so as to be cost neutral (or negative). Then, sadly for you, it’s game over for imperial road signs—and possibly those touting `expensive job creation schemes’, too…

    p.s. I don’t understand imperial miles or `yards’ and you cannot make me :-p.


  40. @Lee – Imperial. Units are used on British road signs to keep the whingers quiet. If you look at any road plans, you will see that they are in metres – why else are marker posts and driver location signs in metric units? Also, why are “200 yard” warning signs placed 200 metres from the obstruction to which they refer?

    Please do yourself a little favour – next the road where you live is resurfaced, check to see whether or not numbers have been painted on the pavement. These numbers give the location of the resurfacing in metres from some reference point.

    So back to your question. Why do you expext road workers to use metric units when they are on the job, but to use imperial units when they are off the job?

    Finally, the conversion from imperial to metric units started about 90 years ago when the War Office realised that the maps they “borrowed” from their allies the French and the Belgians were much easier to use than the yard-based British maps. If you go to the Churchill’s underground bunker and check the maps on the wall, you will notice a metric grid. For the record, that was the “military grid” – a new “civilian grid” had been under preparation since 1938. This “civilian grid” is the current OS National Grid. When estimating distances on a map, I frequently count the squares and the result is in kilometres or 10’s of kilometres, depending on the map scale.


  41. @Lee Price: “Everyone in this country, understands miles & yards”

    No, they don’t. People that understand miles and yards are in a small minority. A YouGov survey showed that 76% of people do not know how many yards are in a mile.

    Click to access sam-exec-summary.pdf

    Continuing to put up road signs that the vast majority of people don’t actually understand seems like a poor use of resources to me.


  42. @Lee Price: “Everyone in this country, understands miles & yards”

    Over recent years I’ve done a bit of a social experiment… now if I convey a measurement I’ll usually do so in metric, it’s only really the use of km that guarantees a response and in the ensuing discussion I’ll ask the question “Ok then, how many feet (or yards) are there in a mile?”

    The answers generally range between “Hmm”, “I don’t know”, “I’m not sure” to “Is it 1000?” I can’t say I actually recall getting anything like a correct answer from anybody. My target audience for this is in the age range of 20-50, British, gainfully employed and seemingly well educated (including my sister who is a biology professor at a university and gave me the “1000” response).

    It’s also unusual for anybody to respond to “How many pounds are there in a stone?” without stopping and thinking about it.


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: