Imperial confusion on new tunnel signs

Transport for London (TfL) was today criticised by the UK Metric Association (UKMA) for bungling the erection of new signs at the Rotherhithe tunnel, including banning all vehicles over 33 inches long from using the tunnel – and for wasting up to £6000 on erecting or amending new signs that will soon be obsolete.

This is the press release issued by UKMA on 26 March.

LONDON, 26 March 2010. Transport for London (TfL) was today criticised by the UK Metric Association (UKMA) for bungling the erection of new signs at the Rotherhithe tunnel, including banning all vehicles over 33 inches long from using the tunnel.

Warning signs at low bridges and tunnels are normally signed in metres as well as feet, following Department for Transport (DfT) advice to reduce the number of large vehicles getting stuck and causing delays, particularly foreign goods vehicles.

However, TfL recently spent over £6,000 on new restriction signs at the tunnel entrances, but failed to add metres to many of the signs at the southern end, despite increasing problems with over-height vehicles at London’s river crossings (see pictures below).

Even more bizarrely, not only is the 10 metre length restriction still not posted in metres, but new signs have been erected which ban all vehicles longer than 33 inches from using the tunnel, instead of 33 feet.

UKMA Chairman Robin Paice said, “It beggars belief that new height restriction signs have been installed at the Rotherhithe tunnel without following long-standing national guidance and including metres, which could have been added at no extra cost and reduced the delays incurred whenever over-height vehicles try to enter the tunnel.”

“At the northern end, metres are included on the height and width signs, but not on the length restriction. Even those erecting the signs clearly don’t understand the imperial units very well, having signed the 10 metre length restriction as 33 inches!  If the government allowed the simple 10 m restriction to be added it is highly unlikely that the wrong measurement would have been posted as it would have been quite obvious that the signs were wrong.”

In 2009 the Department for Transport announced a proposal that the current recommendation that metres should be included on height restriction signs should become mandatory – meaning that the new signs will need to be replaced again.

When asked what plans TfL  had to implement the DfT’s 1990s advice to add metres to height restrictions, TfL replied that “currently there is no programme to replace any signs which remain legal. If the use of metric becomes mandatory, a cost effective programme will be put in place to update all of the non-compliant signs.”

Robin Paice responds, “It is extraordinary that rather than implement the DfT’s guidance at no cost when new signs are erected, TfL would rather waste money on new signs which will shortly be obsolete, and which increase the risk of accidents on London’s main roads.”

UKMA is calling on all highway authorities to update their vehicle restriction signs to include metres in accordance with DfT advice at the earliest opportunity, rather than waiting for the deadline for mandatory replacement of imperial-only signs to approach.


Traffic Signs Manual Chapter 3

Department for Transport, 2008

On width signs (para 5.36):

“It is recommended that this sign [metric and imperial] is used in preference to the sign to diagram 629 [imperial-only signs].”

On length signs (para 5.38):

“It is recommended that both the imperial and metric sign should be used wherever practicable.”

On height signs (para 5.42):

“It is recommended that the sign to diagram 629.2A [metric and imperial] is used in preference to the imperial-only sign.”

Draft Traffic Signs (Amendment) Regulations and General Directions (TSRGD) 2010

Department for Transport, September 2009

Draft changes to the regulations to come into force in Spring 2010:

“Width and Height Restrictions

2. We are making changes to require both metric and imperial triangular warning signs to be displayed to give warnings of restricted headroom, with the upgrade being complete in four years’ time. Using the imperial sign on its own will no longer be permitted.

3. We are making similar changes to require both metric and imperial measurements to be displayed on all width and height restriction roundel signs, with the upgrade being complete in four years’ time. The current imperial-only signs shown in diagrams 629 and 629.2 will be withdrawn.”


All photos by UKMA. News organisations are free to use any of these photographs to accompany this story, with or without credit to UKMA (but not credited to others).

1-New panel missing height metresPicture 1: New panel at Rotherhithe tunnel with height in feet only

2-New panel missing metresPicture 2: New panel at Rotherhithe tunnel with height and width in feet only

3-New sign 33inch length restrictionPicture 3: 10 metre length restriction signed as 33 inches (or around one metre)

4-Close up 33inch length restrictionPicture 4: Close-up of 10 metre length restriction signed as 33 inches


22 thoughts on “Imperial confusion on new tunnel signs”

  1. This is clear evidence, if any were needed, that the quaint old-fashioned imperial system of measures is not actually understood by the people of Britain. The sooner we get on with the job of obsoleting these ancient measures and implementing modern metric-only signage on all our roads the better.


  2. Despite having the pro-imperial lobby ramming it down our throat that “Brits don’t understand metric”, we have here yet more evidence that even those responsible for our safety don’t understand imperial measures.

    The fact that this sort of thing is happening at a cost to the taxpayer which in the long term may be more than it would have cost to metricate properly in the `70s is just adding insult to injury!

    If only the national press, who always seem ready to bash the metric system, would take on this waste of time and money and encourage the government to do the job properly.


  3. If only signs had been made mandatory metric years ago. I recall in the 1980s seeing some metric signs for height restrictions, but I am still waiting for the full metrication of road signs. TfL are just wasting public money putting up imperial only signs, especially when no one who worked on the signs understood them! We have an ever-decreasing educational standard in the UK and eventually most young people will understand neither metric nor imperial. But if the roadsigns were metricated now, at least there would be no confusion over the imperial measurements. I doubt if any young person today could specify more than 1 or 2 imperial conversions (e.g. how many feet in a yard?). If metric is taught properly, it is very easy to use.


  4. Just as Lord Howe contributed so eloquently recently in the House of Lords to the discussion of the muddle in the NHS’ use weighing machines, I hope this might be an opportunity for the gentleman to raise the issue of signage with the appropriate minister in the House of Lords given this appalling sign (no pun intended) of how long overdue the use of metric on road signs has become in the UK.


  5. Unfortunately I believe that this is a mistake rather than people thinking that vehicles over 33 inches long are not allowed. Worst still I suspect that people will see the sign and ‘autocorrect’ it because it would be seen as obvious from the mistake. It’s a bit like signs that say “Parking 2m” – people do not think that the parking will be 2 metres from the sign. They would do this by weighing up the odds of whether this means miles or metres and apply common sense accordingly. Worst still people would know ‘instinctively’ that this would be miles. A disgrace. It is a similar issue to the 33 inch vehicle though. This does not make up for the sloppy way metrication is being handles in Britain. It’s a disgrace. When we can truly make people not know what 33 inches are, that will be when we will have dragged ourselves into the 21st century. ‘Miles’ will be trickier but even those measures will completely disappear from the British mind just as it has in Australia and Ireland. Bring it on!


  6. I was just re-reading the brochure “Traffic Signs 2.0” published by the UKMA (copyright 2009). On page 2 it states:

    The symbols used on road signs for feet and inches are … incorrect.
    The symbols, as listed in the Units of Measurement Regulations 1986, are
    ‘ft’ and ‘in’.

    Does that mean that the use of the single quote for feet and double quote for inches on restriction signs violates the Units of Measurement Regulations? And does the DfT (or anyone else in the government) much care? [ Editor – Yes, it does mean that. Schedule 1 (3) of the Regulations reserves single and double quotation marks to mean respectively minutes and seconds of angle. The DfT chooses to ignore this]


  7. What a mess!

    It’s bad enough that we see dual signs in some places in the country and imperial only at others, but when we see the same ambivalence at a single location that’s even worse!

    Clearly, if metric was the norm, none of this uncertainty would prevail and the signs would be simple and uncluttered.

    Whilst we might accept dual signage as a transition to metric, this example shows the unsatisfactory state of affairs being stored up by present DfT policy, which rules out the only sensible solution to the whole thing.


  8. In 2009 there was a DfT consultation:-
    The Government’s aim is to make Britain’s roads the safest in the world.

    Click to access roadsafetyconsultation.pdf

    Comments by Jim Fitzpatrick MP (Parliamentary Under Secretary of State for Transport), include:
    “We are among a small group of leading nations on road safety, but we believe that our proposals for a new approach to road safety and for new safety measures can make Britain’s the very safest roads in the world. This is an ambitious, but achievable, vision.”
    “So I encourage you to let us have your views on road safety and on our proposals, to help us to make our roads the safest in the world.”

    Submissions were made requesting metrication of road signage. Copies of the UKMA’s brochure “Traffic Signs 2.0? were sent to the DfT.

    In separate correspondence to the DfT I asked:
    *How long will it take for the DfT to ensure that Britain’s roads are the safest in the world?
    ** When do you think Britain’s roads will be the safest in the world?

    In their replies answers weren’t provided.


  9. @Phillh – Unfortunately while your argument is sound, people of a lesser intelligence will trott out the old “when there was no metric it was less cluttered” remark – citing that it works both ways. The fact that these people are wrong and we are obviously right is beyond them of course.


  10. In my view the ideal way to convert warning signs from imperial to metric is to use metric only on the sign itself with the imperial on an “information sign” (yellow with a black rim) below the sign. The information signs would be in smaller text than the official sign and would just not be replaced once they reached the end of their useful life.

    The other law that I believe runs contrary to the EU directive is the requirement for all vehicles over 3 metres in height to have their height quoted in feet and inches in a location where it is visible to the driver. Hopefully this will change once the new “dual unit” signs are brought it. Of course, if it becomes mandatory for “large” vehicles to have their dimensions displayed in metric units, the transition described above will not be necessary.


  11. Two reforms can help to minimise bridge strikes. The first is to have metric heights on all the bridges. The second reform is to require all vehicles over 3m in height to have the height displayed in the cabin. If the height displayed in the cabin is in metres, then the heights in feet and inches will become superfluous and may be dispensed with at a later date. Therefore, the thing to push for is having the height of the vehicle displayed in the cabin in metres.

    But why metres? Well, it is obvious that British trucks occasionally are driven on the Continent and the Irish Republic, so it makes sense to have the heights in the universal measurements, especially as these measurements are now being made mandatory in the UK.

    What if the Minister or the Department of Transport insists on the height being displayed in feet and inches as well as metres? That’s obviously second best, but it’s better than nothing. The essential thing is to get the height of the vehicle displayed in metres in all truck cabins. This could be a condition of registration, so that this requirement comes in over the course of just one year.

    It is not acceptable for the height of the vehicle to be displayed in feet and inches only. Trucks go to the Continent from England and to and from the Republic of Ireland from Northern Ireland. Therefore feet and inches only is not in the public interest. The only acceptable arrangement is for the height of the vehicle to be displayed in metres in the cabin, with – or preferably without – the equivalent in feet and inches. This is something that must be pressed on the Minister and the Department of Transport.


  12. I quite agree with Michael Glass. I would only add that lengths be displayed in meters also on tractor-trailer trucks (articulated lorries) to take care of those instances where length restrictions are posted also.


  13. The potential argument that we can reduce clutter by imperial only as well as metric only doesn’t answer the point that metric indications, like it or not, are now recognised as indispensable.

    Now that metric indications for height, width and length restrictions are being made compulsory for future signage the next logical step is to make sure that all future HGV drivers understand metric. This should be part of training and testing.

    HGV drivers with a British license are entitled to drive anywhere in Europe. A condition of that license should be a reasonable comprehension of metric indications. The new signage rules will mean that a comprehension of imperial can be optional even in the UK.


  14. I responded to the Government consultation and suggested that over a period of time (I think I said 5 years), in cab information should be switched to being metric only. I suggested that it be part of a vehicle MOT and it would allow all imperial measures on restriction signs to then be phased out leaving metric only. I referred to a previous DfT correspondance that stated than km could not be shown against miles (distance or speed limits) as it would create clutter and be hard to read. I also made the usual points about metric only being the norm in car parks, ferry terminals, garage forecourts etc without any problems being caused. Keeping imperial is expensive, unnecessary and makes signs hard to read. Whether or not the finalised TSRGD or future amendments reflects this remains to be seen.


  15. I see that the local newspaper is reporting that TfL has now removed the offending sign. See It would be interesting to know whether they are going to correct the other mistakes – especially changing the imperial-only signs for dual signs in accordance with the new rules.


  16. Of course, the officials were quoted in the article as saying there are no requirements to post restrictions in metric. They conveniently omit the fact that those requirements are coming soon.


  17. I use a bus to get to and from work and above the driver it says – ” Vehicle Height 13′ 10″ and then underneath (4200 mm). At the front next to the door is a metal plate certifying the bus, with every height, width and length measurement listed in mm. Its ridiculous that the vehicle has been constructed entirely in metric and then the height is listed in feet and inches more prominently for drivers, with metric in brackets.

    Also the speedometers seem to have km/h more prominently than mph – imagine your car’s reversed with mph on the inside and smaller than km/h. Even on the newer ones, there is an analogue mph speedo, with a digital km/h underneath!


  18. Having read the comments above, I can’t help stating the obvious: Education first, mandating second. Both in the UK and in the USA, people in charge of measurements, teachers, legislators, government officials and traffic coordinators have proven time and again that they do not understand SI (the streamlined version of the metric system), and the Imperial system is just vaguely familiar to them. Instead of looking for faults or persons to blame for this, let us start a comprehensive training course for the teachers of the metric system, thereby guaranteeing that the inormation they pass along will be flawless and logical. Then, we can streamline legislature to post correct metric signs on the roads, on the groceries and on wine bottles.


  19. Isn’t proper education going to take government commitment to full metrication? I can hardly imagine that taking place without it.

    As Shakespeare wrote (and Hamlet said): “Aye! There’s the rub!”


  20. Like most things in life it is difficult to learn how to use the metric system in a vacuum. People need to see it in action and be encouraged to adopt it.

    It isn’t rocket science but what people cannot cope with is two incompatible systems both in use and at the same time.

    Metric units have been around in the UK for decades. It is the failure to decisively phase out imperial that has prevented people from learning to use it properly.


  21. Philh,

    I agree. That is certainly the case in the US. I wasn’t sure enough to say anything about education in the UK.

    I am sure there are some problems in education about the metric system, but they arise primarily because one learns it in school and then forgets it. The teachers have no practical experience with it, even though everyone has learned it in school for decades.

    I don’t think education can improve until there is a commitment to using it (and phasing out Imperial/Customary.) Both of our countries seem deeply committed to dragging out the process forever and never completing it. Bothly sadly need a JDI (Just Do It) process.


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