Metres and yards – now interchangeable?

A reader of Metric Views has drawn our attention to a paragraph in the DfT Traffic Signs Manual that allows distances shown as ‘yards’ on some traffic signs to be measured in metres. We wonder if this idea on interchangeability has spread beyond the DfT.

The only official use of the Imperial yard in the UK since 2000 has been â??for traffic signs and for related distance â?¦ measurementsâ??. As civil engineering was one of the first sectors of the British economy to go metric, in the early 1970â??s in fact, the continuing use of the yard can present problems for contractors.

One of our readers has shed some light on this. He writes:

â??Looking for something totally unrelated on the DfT website I came across this paragraph in Chapter 8 Appendix A1 of the Traffic Signs Manual (

â??7. The siting distance of the first sign is given in metres or miles. However, to comply with the Regulations the distances on supplementary plates must be shown in imperial dimensions. Tables and plans show the placing of road works signs in equivalent metric dimensions; this utilises part of the permitted 10% tolerance on the placing of signs (Part 1: Design, paragraph D4.4.7), e.g. signs showing 400 yards being placed at 400m.â??

If I’m reading this right that they’re basically saying the distance between the signs is in metres but because of regulations we have to use the word yards on the sign.â??

Metric Views has suspected for some time that BBC reporters use metres and yards to mean the same thing. If this catches on, then what future is there for the yard, except as a comfort blanket for the insular?

12 thoughts on “Metres and yards – now interchangeable?”

  1. The diagrams in the document (for example the diagram on page 75) explicitly specify that “200 ydâ€? warning sign should be placed 200 m from the obstruction. The same rule holds for “400 yd” and “800 yd” signs.

    It is a pity that these regulations make no provision is made for “500 yd” or “1000 yd” signs event though they are permitted by the TSRGD 2002.


  2. I was able to scan through the document and found more pages with the same situation. That is where signs marked as xxx yards are to be placed as xxx metres. See pages 172-183, 190, 191 193, 200, 227-230, 233.

    There are most likely more, but this is all I looked at.

    I wonder how it would work if the signs didn’t bother to use the words yards or metres and just showed the numbers. This way the numbers will mean metres.


  3. In response to Daniel we already have this – signs with no units shown denote miles.

    Unfortunately, there are a number of signs where somebody has deemed it necessary to add the letter “m” after the number, hence giving the Department for Transport another excuse not to allow “m” on distance signs to mean metres.

    What makes the thing worse is that British drivers are expected to know from context that “m” on a distance sign means miles yet the same thing on a height or width sign means metres. It seems that our government doesn’t deem us intelligent enough to deal with more than a few metres at a time unless they’re labelled “yards”!


  4. I didn’t realise at first, but it these signs are only temporary ones used at construction sites. Are these rules also true for permanent signs? Even though the manual has nice, pretty diagrams with accurate metric placement, it may be the case that these temporary signs are not placed precisely or even close to the metric distance they are suppose to be at.

    I’d be more concerned where the permanent signs are placed.

    Alex, I was referring to unit-less signs for metres. If this were the case, then all short distance signs could be placed at true metric distances (if they are not already) and be stated as such. If a Luddite wants to think the numbers mean true yards, then let him/her be fooled.

    Any idea how often a mile is measured out as 1600 m?


  5. Not far from me, a fairly new roadsign has been erected showing a road junction ahead. The road forking off has a height restriction in metres and feet shown, but the interesting thing is that the distance to the junction is given as “500m”. Even if this is an accurate measurement as this thread implies, I am mystified how such signs get through a system that prohibits the use of metres for distance purposes. Is there no such thing as quality control or could it be that the Department for Transport is happy to turn a blind eye to these errors (albeit welcome errors) as part of a process to familiarise the public with metres ahead of any relaxation of the law? It might seem like wishful thinking but the government’s approach to metrication has always seemed slightly underhand. I wonder what others think and if anyone has any understanding of the process that leads to the design and manufacture of roadsigns.


  6. Again responding to Daniel – there are permanent signs near my home which also follow this rule (the road has markers at 100 m intervals and signs showing pedestrian crossing in “400 yards” exactly 4 markers away) so it is applied in other areas. Only part of the Traffic Signs Manual is currently available on-line so other examples of this “approximation” may become apparent in the future.

    I did understand your question with regard to “unit-less” signs, which continues the theme of how “intelligent” our government thinks we are. The UK isn’t large enough to show long distances in anything more in hundreds of miles so its unusual for distaces to be over 100 miles – short distances such as approaches to junctions and motorway services are the only ones which would have an “m” to mean miles, but we’re seemingly not intelligent enough to know the difference between “London 120” and “Services 500 m”.


  7. Keith asked what sort of quality control there was on road signs. My understanding is that road sign QA works as follows:

    1) The DfT publishes new version of the TSRGD from time to time and also manuals for the building of roads. The last version of the TSRGD was issued in 2002.

    2) The owner of the road uses the manuals and builds the road. In the case of trunk roads, the owner is the Highway Agency while most other roads are built by the local authorities, though other agencies such as MoD or private concerns sometimes build their own roads. The DfT does **NOT** QA the road designs.

    3) If the owner of the road wishes to use a sign that is not in the TSRGD, they should apply for permission to do so from the Secretary of State for Transport (in England) or similar person in Scotland or Wales. For example, the Driver Location Markers that are now being erected on our motorways were approved by the Secretary of State. If they fail to apply for permission before erecting the sign, the permission may be granted retrospectively.

    4) The QA of road design is exercised by somebody objecting to a sign. Under the 1985 Act, the objection should first be directed to the “Owner� of the sign. If the owner does nothing, then the objection should be directed at the Local Highway Authority. If they do nothing, then the objection should be directed at the Secretary of State.

    5) If the Secretary of State chooses to do nothing, then I believe (the Act does not say anything in this respect) that the plaintiff can raise a court case against the Secretary of State, but in practice, if this happened, the Secretary of State would probably grant retrospective permission for the sign to remain in place.

    6) ARM (Active Resistance to Metrication) often cite the 1980 Act which gives the public permission to remove “illegal signs�. It is my understanding that the 1985 Act overrides this permission (under the Henry VIII principal which was cited by the so-called “Metric Martyrs� in the case Thoburn et al vs Sunderland City Council et al) except in cases where the “owner� of the sign cannot be traced.


  8. Daniel says “I didn’t realise at first, but it these signs are only temporary ones used at construction sites.”. I think he is correct. I have read a few other official documents and they quote signs of, say, 200yds being xyz metres away. So I guess it has something to do with application rather than “across the board”. Having said that – for small distances I don’t think anyone can realistically “sense” a difference between 200 yds and 200 m – they are very very close if you are driving at anything more than 10 or 20 km/h.


  9. It seems to be the case that the 3-2-1 countdown markers at motorway exits are now possitioned at 300, 200 100 metres on newer motorway junctions. On older juctions you will find them at 270, 180, 90 metres (and in the Highway Code, of course, it says they indicate at 300, 200, 100 yards).


  10. It’s not just temporary signs that we’re talking about… Dave Brown mentions the junction countdown markers and just last night I spotted some signs on the A14 in Northamptonshire, the signs indicate 400 yards to a pedestrian crossing, the sign is located right next to a marker post, the crossing itself is right next to a marker post too, exactly 400 metres from the sign. This is the same in both directions!

    I’m sure if we looked we’d find hundreds of similar examples!


  11. “It seems to be the case that the 3-2-1 countdown markers at motorway exits are now possitioned at 300, 200 100 metres on newer motorway junctions”

    I wish this were true. There are a number of new exits near me and the 3-2-1 markers do not line up with the emergency locator / rescue signs placed precisely 100 m apart. The “slightly less” distance stinks of yards to me – and it just goes to show that even with new signs there’s a right old mix!


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