City of London’s 15 mph plan was another missed opportunity to introduce km/h

Between 2019 and 2022, the City of London planned to become the first UK region with a 15-mph speed limit. This plan was blocked by the Department for Transport because speedometers are not accurate enough for low speeds. It meant that it was not technically possible. Like the mass rollout of the 20-mph speed limit, the plan for a 15-mph speed limit across the City of London was another missed opportunity to introduce km/h speed limits.

This would have involved no extra public expenditure. The new 25 km/h signs (instead of the proposed 15 mph signs) could be distinctive in some way, perhaps with a km/h symbol on the signs. This opportunity was missed when the 20-mph speed limit was introduced on minor roads across London. Instead of replacing lots of 30 mph signs, the authorities could have kept them and just added a “km/h” symbol to the signs, using vinyl overlays – 30 km/h is almost the same as 20 mph. This could have been officially authorised by a change to the TSRGD or by the Secretary of State for Transport using a Statutory Instrument. Alas, the political will was lacking and still is.

For years, the Department for Transport has been telling the public that “the significant costs involved for the UK in changing the measurements used on signs, replacing signs, providing safety and publicity material and the consequential costs for businesses and other organisations would far exceed any benefits in terms of meeting the EU’s objectives.” and that “we do not consider that diverting funding from high priority areas for the metrication of traffic signs is justified”.

Yet there seems to be an unlimited budget for any number of new 20-mph speed limit signs, road markings, roadside messages and publicity campaigns without any discernible impact on other parts of the transport budget. Somehow the authorities find all this extra money.

If the DfT gave the City of London the go-ahead, the funds would have been found somehow to implement the new 15-mph speed limit. Surely, this would involve replacing some signs, installing new signs and running a public information campaign. The introduction of new speed limits would surely involve a publicity campaign to raise public awareness. I have seen some banners on lampposts and “Twenty’s plenty” messages on large signs to inform drivers about the 20-mph speed limit.

The DfT always says that no money can be found for introducing metric speed and distance signs without diverting money from other parts of the transport budget, but it seems that any amount of money can be found for new signs, messages and road markings for new mph speed limits. Nobody at the DfT ever argues that it diverts funds from other parts of the transport budget.


16 thoughts on “City of London’s 15 mph plan was another missed opportunity to introduce km/h”

  1. Just like the unfortunate political pandering the current government is engaged in when it comes to irregular migration to the UK in rubber boats, the government is pandering to a certain segment of the political influencers who want nothing to do with Europe and want to control the economy for their own short term benefit.

    Any irrelevant or even harmful policy is fine with them if it helps them maintain power even if hurts the rest of the country. Hence their unwillingness to finish the job of metrication by converting road signs, etc. to harmonize units of measurement with the rest of the world outside the USA, especially Britain’s largest trading partner, the EU.

    So sad and deplorable. Maybe a new government will see things differently?

    Liked by 2 people

  2. Ezra Steinberg said:

    “So sad and deplorable. Maybe a new government will see things differently?”

    I highly doubt it. Most people are clueless on how governments work. They falsely believe that the elected person is the real leader. In truth there are men behind the curtain who pull the levers. The political “elected” official is just an image on the wall that the population can blame when something goes wrong.

    The EU, especially Germany is under US control. Germany is not an independent, free country. It is still under US occupation. England is to some extent more independent now that it is outside the EU but tries it hardest in seeking the American Oligarch’s approval in everything they do. Who knows, chatter of returning to FFU in England may be a vain attempt by the rulers in London to kiss American arse and obtain American favours?

    We see how this all plays out in reactions of the Leaders in Europe towards Russia in the Russian-Ukrainian war.


  3. A speed limit of 25 km/h/15 mph does seem a bit odd. Given that an advantage of metric speed limits is that they allow more options in rounded numbers, in regards to urban speed limits, you not only get the option of 50 and 30 km/h but also 60 and 40. While the insistence on rounded mph speed limits means that the only realistic options are 20 mph and 30 mph, with those being roughly equivalent to 30 and 50 km/h, respectively. 40 km/h would be an ideal speed limit on a lot of urban roads, but it uniquely remains unavailable in the UK due to the persistence of using mph speed limits, which are multiples of 10.

    Generally, setting speed limits below 30 km/h/20 mph​ is quite impractical for public roads, which is why you tend to only see them on private property.

    @Erza is spot on. The whole reason why imperial has persisted for this long is because successive politicians lacked the courage to do anything about it and allowed political inertia to sink it so refuse to see it as a problem.

    It is beyond time that they ripped the ban aid off, and ultimately they have nothing to worry about long-term. The cost would be utterly insignificant in the grand scheme of things and people would quickly get use to it. It wouldn’t be long before people would be wondering what the fuss was about. The continuation of miles on road signs is ideologically cowardly incompetence.

    Liked by 1 person

  4. The current 25 km/h rule comes from EU directive 2002/24/EC. This directive, which relates to electric bikes which are limited to 25 km/h and a 250 W motor.

    Liked by 1 person

  5. This discussion got me thinking about road signs in other countries (aside from the dismally backward USA) that supposedly still use “mph” for speed limits. So, I searched for speed limit signs in Liberia and found these three links:

    Based on the road sign images at the top of the first website and the description of speed limits at the second and third websites (scroll down a ways for that), it appears that Liberia has settled on “km/h” (or maybe “km/hr”) rather than “mph” for posted speed limits on their roadways.

    As for Myanmar (or Burma) I found these websites:

    and this image:

    All of this leads me to believe speed limit signs in Myanmar are now metric (at least in the big cities or wherever newer signs have been posted). I note that older websites use “mph” where they mention speed limits, so this posting of metric speed limits on the roadways may be a fairly recent development. This may also explain why some speed limits appear to have oddball values that are presumably soft conversions from the old Imperial speed limits.

    That would leave only the UK and the USA on planet Earth where Imperial speed limit signs are still being used.

    Liked by 1 person

  6. Thanks Martin, it did seem odd that they would be considering such a speed limit on public road traffic. TFL do seem more progressive in this regards but are being held back the DFT’s insistence on using imperial units. The Mayor of London even Tweeted this Yesterday.

    “By 2024, 220km of @TfL’s roads will have a 20mph speed limit, making London’s roads safer for everyone.”

    Ezra Steinberg

    Belize uses miles as well. The signs in Belize look similar to those in the USA.

    As does the Bahamas

    Interestingly, Samoa uses duel mph/km/h road signs being the only country to do so. As can be seen on page 13 here.


    And here is an example in real life.

    Liberia is in a period of transition and is phasing the mph signs out gradually. Which given that Liberia is a poor African country of about 5 million actually make sense as opposed to the DFT looking for an cop out not to. Similar story with Myanmar. The idea that Myanmar, Liberia and the USA being the only 3 non-metric countries came a CIA World Factbook report from the turn of the millennium.

    Liked by 1 person

  7. Alex M wrote: 40 km/h would be an ideal speed limit on a lot of urban roads, but it uniquely remains unavailable in the UK due to the persistence of using mph speed limits, which are multiples of 10.

    So the DfT sees multiples of 10 as a sure and safe way to regulate speed limits but does not allow those multiples to be of the units taught in school. I cannot imagine that any other in the world teaches metric units to children at school but refuses to allow those same units to be shown on road signs, which are one of the most prominent places where measurement units are visible to the general public. It verges on lunacy not to allow them. Multiples of 10 mph are very large increases (or decreases), around 16 km/h per step. Road signs in km/h with multiples of 10 allow for a broader range of speeds to be used. If one is honest, Britain doesn’t have a proper system of measurement at all.

    Liked by 2 people

  8. metricnow

    “Britain doesn’t have a proper system of measurement at all.”

    Officially, the UK government is supposed to be metric. Once you remove the units on the road signs out of the question. The only two other permitted non-metric usage are pints for draft beer/cider and Troy ounce for precious metal. Both of which are very situational and nowhere near as egregious as the continued usage of imperial units on the road signs. Which just goes to show how much of an elephant in the room it truly is.

    Liked by 2 people

  9. @Alex M I often wonder if some of these YouGov surveys are targetted in some way. I get a daily email from them asking me to take polls which I always read and I don’t recall this one ever being on my radar!


  10. Alex M wrote:

    “However this doesn’t mean that any switchover wouldn’t go smoothly and people would quickly get use to it (kilometres for speed and distance).”

    I don’t remember there being such a public survey before decimal currency was introduced. I was young at the time but I remember a few people sounding off against it in the newsreels of the day, but as you said, people quickly get used to new things if they have to. I don’t really see why the government would actually run a public survey on whether road signs and speeds should be expressed in the units which have been taught in schools for the last 50 years. It simply makes sense to do so. It is an abdication of governmental responsibility not to lead the way on this issue. There is nothing inherently better about miles and everything better about using kilometres, especially as metres are already very much embedded in the public’s mind for shorter distances of several hundred metres. It simply makes sense to count those metres in thousands and use the term kilometres. It doesn’t surprise me one bit that the result was that people preferred the status quo, if they are asked such a question. If they had done such a survey in the early 1970s to ask if people would like to switch from shillings and pence to decimal currency, I’m sure the public would have voted for the status quo back then too. Sometimes the government needs to take the lead and not hide behind the cloak of what it seems the public prefers.

    Liked by 2 people

  11. @AleX M: I looked at the various breakdowns (age, gender, region etc) in teh survey and the biggest outlier was the way in which London was so different to the rest of the country – far more so that the spread of views by age, gender, polical views or socio-economic banding.

    In teh coutnry as a whole only 11% strongly supported a change to kilometres while 44% strongly opposed such a change – a ratio of 4:1. In the case of London, the figures were 19% vs 26% which si a ratio of 1.35:1.


  12. Herin lies the actual problem. We have governments who do best for them rather than what is best for the country. Opinion polls (and poorly executed referenda) are more important to those in Downing Street and Whitehall because they win elections in the short term and even a progressive government will at the moment shy away from something that might be good for us all if their popularity will plummet.

    That said I’m still not convinced that this particular poll was representative of the wider population!

    Liked by 1 person

  13. We need to acknowledge, of course, that there is a lot of opposition to 20 mph speed limits, together with road humps that are sometimes used to try to enforce them. It is likely that there would be even more opposition to 15 mph speed limits. Some, on reading this news, will breathe a sigh of relief the 15 mph speed limits are not going to happen.

    But that is not the point.

    The point is that the DFT has fouled itself by failing to move with the times. If metrication of road signs had have gone ahead in the 1970s, as originally planned, the DFT would not now have found itself in the situation where it was unable to introduce a new measure because of the inflexibility of the imperial system.

    For how many more years will the DFT hamper its own intentions because of its reluctance to face the future?

    Liked by 1 person

  14. One of the most important questions that is missing from these questionnaires is the frequency with which people actually use the measurements in question. Should everybody’s answer get an equal weighting?

    If somebody weights themselves frequently (I weigh myself and log the results once a week as part of my diabetes management regime). Should my views count more than the views of somebody who weighs themselves once every six months? Likewise, should the units of measure preferred by mountaineers take precedence over the views of the public at large, even though mountaineers form a small percentage of the population?


Leave a Reply

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

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

Facebook photo

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

Connecting to %s

%d bloggers like this: