No DfT research on familiarity of road sign units

A Freedom of Information response from the Department for Transport reveals that it has done no research on the general public’s familiarity of road sign units. The DfT once used the lack of metric education as an argument against the metrication of road signs but has never seen the lack of familiarity with imperial units as a problem with its current use of imperial road signs.

On 31 January 2022, I made a Freedom of Information request at the DfT asking:

“What research has the DfT done or sought from other sources to find out how well the general public understands miles, yards, feet, inches, kilometres, metres and other measurements used on British roads?”

On 28 February 2022, the DfT sent me the following reply:

“Following a thorough search of our paper and electronic records, I have established that the information you requested is not held by this Department.

I can confirm that there has been no research done by the Department, or sought from other sources, on how well the general public understands miles, yards, feet, inches, kilometres, metres and other measurements used on British roads.”

The imperial system has not been taught as a separate measurement system in British schools for decades. In the Department for Education’s statutory guidance for mathematics programmes of study in the National Curriculum in England, there is a Measurement section that states what pupils are expected to be taught. One of the items in the list under this section states that pupils should be taught to “understand and use approximate equivalences between metric units and common imperial units such as inches, pounds and pints”. In other words, only conversion factors between common imperial units and metric units are taught. Apart from that, it is metric all the way.

Despite the fact that relationships between different imperial units are not taught in British schools and have not been taught for decades, the DfT still expects young drivers to be familiar with the miles, fractions of miles, yards, feet and inches used on British road signs. The DfT has never seen this as an issue for imperial usage on British roads.

However, the DfT once claimed that drivers who have not received metric education at school would be confused by a change to metric units (Parliamentary Written Answer, 11 July 2002, Hansard, Col 1116w). Subsequently, it was suggested that conversion might be considered when a majority of drivers had received metric education.

The UK has already passed this point because metric units have been mandatory in state schools since 1974, and therefore all drivers who were born after 1964 will have received their secondary education using metric units. In any case, evidence from other countries’ changeovers demonstrates that such “confusion” is not a significant problem.

Why did the DfT see this as an issue for metric units but never for imperial units? The DfT does not mind if you do not know the number of inches in a foot or the number of yards in a mile. This information does not appear in DfT publications.

In 2013, the UKMA commissioned YouGov to do a survey to find out the public’s understanding of the imperial and metric systems. This survey showed that the public were more familiar with the metric system. It revealed that 76% of respondents were unable to answer correctly how many yards there are in a mile and 43% could not say how many metres there are in a kilometre.

Despite the UKMA findings that over three-quarters did not know the number of yards in a mile, despite the widespread usage of both units on British roads, the DfT has never seen this as an issue. So why did the DfT see unfamiliarity with metric units as an issue despite the fact that far more knew the number of metres in a kilometre? How could lack of education be an obstacle to the metrication of British road signs but not with the current imperial road signs?


11 thoughts on “No DfT research on familiarity of road sign units”

  1. Do they not see how patronising it is to claim that the British public is somehow unable to cope with a much simpler system that is almost universally adopted? Somehow the British public are too stupid to cope with something that the rest of the world adopted without much issue.

    I am personally betting that it is a way to excuse the lack of political will to move on from the status quo just like the claims of it being too costly are used for as well.

    Liked by 1 person

  2. Part of a response from the DFT  I received, following a letter to my MP a couple of years ago, was that there was no safety aspect to metricating road signs. A few years ago, on returning home from the Eurotunnel terminal, I had a close call with a French registered car at some roadworks where temporary speed restrictions (in mph of course) were displayed.
    Foreign drivers are not familiar with speed limits in mph, and their speedometers show km/h only. I would have thought this was a safety issue. Has the DFT done a risk assessment on this? I think I can guess the answer to that one.

    Liked by 1 person

  3. I know that there is an artificial distinction made in Britain when it comes to measurements for ‘trade’ and for ‘other purposes’, but I still think it is worth pointing out to the powers that be that it makes no sense, from an educational or any other point of view, to require, say, material to have to be visualised, requested in the shop and worked with in metre lengths, while the highway has to be visualised and worked with in yards, albeit normally hundreds of them at a time. Why are lengths of things bought and the lengths of things experienced in the open environment measured using different units of measurement? The situation becomes all the more ridiculous when it is remembered that there is only about a ten percent different between a metre and a yard. What exactly, I would like to know from the DfT, is the problem with showing distances and height and width restrictions on the road in metres and metres only? Often two signs now appear, one old one in imperial units and one modern one in metric. I recently saw two such signs using a total of three different units of measurement to sign a minor road width restriction (metres, and feet and inches). When it comes to road safety, surely it is safer to have one sign in metric units, the units taught in school now for half a century. Why the need for three different units? If anything is confusing, it is looking at two signs trying to tell you the same thing.


  4. It is not only road signs that cause problems to visiting drivers, but also tyre pressures. The handbooks for many British cars give the recommended tyre pressures in kilopascals and possibly in bars but very few use psi. Yet almost all tyre pressure points that I have come across in British garages default to psi. Why?

    For the record, 100 kPa = 1 bar = 14.7 psi. How many people (British or visitor) know this?


  5. Martin,

    One has to ask how these shops are able to obtain gauges in non-standard units. It obviously shows a lack of cooperation between the various industries. The tyre and automotive manufacturers design their products in SI. There should have been some type of communication between the auto/tyre manufacturers and the companies that design pressure gauges to design and produce gauges that measure and display pascals.

    The shops that have psi gauges have to be buying them from somewhere. If they had stopped producing them decades ago, the old psi gauges would have worn out all been kPa by now. Even in metric Australia, the tyre gauges are in psi and not kPa. Why?

    It’s almost as if the auto/tyre manufacturers as are at war with tyre gauge manufacturers. The gauge manufacturers using FFU hoping it will force the auto/tyre manufactures to switch to FFU as well and the auto/tyre manufacturers using SI with the hope the gauge manufacturers will switch with neither budging. Leaving it to the guy on the street to figure it out. The same is true with bicycle tyres too.


  6. @Daniel – In the United Kingdom tyre pressure gauges and pumps can be found at most garages. You pay your money for five minutes use of the machine, then preset the required pressure and pump each tyre up in turn (changing the preset as you go from front to back). Most machines are set to display psi, but there is a button that switches the machines to bars.


  7. I am surprised (appalled?) that 43% of those asked could not say how many metres there are in a kilometre. This is after nearly 50 years of metric education in schools! I wonder if part of the problem is the way many people pronounce the word ‘kilometre’, as if it rhymes with thermometer, instead of with stress on the first syllable. The meaning of the prefix ‘kilo’ should surely be understood by most people now, given that it is often abbreviated to ‘k’ in running events and in figures denoting salaries to indicate one thousand (metres in the case of sports and pounds in the case of salaries). I wonder if there is some work to be done there.


  8. I think that the real reason can be summed up by the statement often [wrongly] attributed to Confucius “I hear and I forget. I see and I remember. I do and I understand.”. Children might be taught that the prefix “kilo” means “1000x”, but unless they actually put that into practice, they will forget it. One of the best ways to put it into practice in in cooking where grams and kilograms are often used. The next best way is to advertise salaries are being £xk.

    Of course there are some sectors of society who just have a complete blank when it comes to numbers – they will always be with us whether we use yards and miles or metres and kilometres.

    Liked by 1 person

  9. Driver location signs help a driver to use their mobile phones to pass on their location to the emergency services should the need arise. Although all motorways in England (but not Scotland Wales or Northern Ireland) have driver location signs, they are very poorly advertised. In an incident in the Taunton area in 2007 (before driver location signs were introduced on the M5), the emergency services had to mobilise four teams because motorists who phoned in gave misleading information regarding their position.

    Unfortunately driver location signs have been poorly publicised, the reason being, I believe, that they quote kilometres rather than miles. If a similar incident were to occur today, it is still likely that the emergency services would have to mobilise more than one team.


  10. Alex M wrote:
    “Do they not see how patronising it is to claim that the British public is somehow unable to cope with a much simpler system that is almost universally adopted? Somehow the British public are too stupid to cope with something that the rest of the world adopted without much issue.”

    Alex, I have lived in several fully metric countries and live in one now. Not only has the rest of the world (bar the obvious exception) adopted metric but it has done so without any issues whatsoever. I too fail to understand why the DfT seem to think that Britons are incapable of relating to road signs showing the units of measurement that virtually all Brits were taught at school over the last half century. I’m sure that most of the very small minority who are old enough not to have learnt metric at school and who are still driving will have had exposure to metric units on road signs on holidays in other countries. That doesn’t leave many people who will have had no exposure at all. We are in a difficult economic period at the moment, so the DfT would likely claim that there is no money to upgrade road signs to the units taught in school, but this really is an issue that should have been dealt with long ago. The DfT does the country a great disservice by not allowing this upgrade to go ahead, except in piecemeal fashion, almost at the rate of one type of sign every few years.


  11. @metricnow I think that the sad reality is that there is little political interest in seeing progress in this area. As such it is easy for the DFT to make up a pathetic excuse as to why road signage can’t display modern logical units that have been taught in schools for decades.
    Most people are simply happy to muddle on with it and don’t see why it is such an issue. So when someone complains to the DFT it is easier for them to come up with a pathetic excuse like the cost or claim lack of familiarity. When in reality even their inflated cost of £730 million is by no means prohibitively expensive, particularly for a one off expense and the longer they leave it there more it is likely to cost them. While their claim of lack of familiarity is a catch 22 even if it held water.
    Although it does go both ways, as such when it is done it is done and people will quickly move onto other things. People seem to forget how small of a minority the people who oppose metrication really are.

    Liked by 1 person

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