Lack of co-ordination between DfT publications

This week, Ronnie Cohen looks at a problem faced by the UK Department of Transport (DfT) resulting from the our two-system measurement muddle. With continuing staffing cuts in Civil Service and the diversion of effort to deal with Brexit, it would appear that such problems are unlikely to be resolved in the foreseeable future.

The Traffic Signs Regulations and General Directions 2016 (TSRGD) were made on 16 March 2016, laid before Parliament on 22 March 2016 and came info force on 22 April 2016. Since TSRGD 2016 came into force, there have been updates to the online versions of the Know Your Traffic Signs publication and the Traffic Signs Manual (TSM). Know Your Traffic Signs was last updated on 4 May 2016 and the TSM was last updated on 23 February 2017. As the TSRGD 2016 was already in force when the most recent updates were made to these publications, it would be reasonable to expect them to reflect the current regulations regarding the mandatory use of metric units on all new the replaced vehicle dimension signs. However, this is not the case.

All references to vehicle dimension signs in the TSRGD 2016 make it clear that the metric units are now mandatory. Imperial-only versions of the new and replacement signs are no longer authorised, though existing imperial-only vehicle dimension signs can remain in place until they become life-expired or are due for replacement. Here is a summary of all the references to vehicle dimension signs that I have found in the TSRGD 2016:

  • Sign table — Schedule 2, Part 4, Item 2 on page 55 shows Diagram 530A. It shows a dual triangular height limit sign.
  • Sign table — Schedule 2, Part 4, Item 3 on page 56 shows Diagram 531.1A. It shows the maximum headroom available at arch bridge ahead with two triangular signs with images of arched bridges (one imperial and one metric).
  • Sign table — Schedule 2, Part 4, Item 5 on page 57 shows Diagram 629.2A. It shows a dual circular height limit sign.
  • Sign table — Schedule 3, Part 2, Item 25 on page 73 shows Diagram 629.1. It states that vehicles or combinations of vehicles exceeding the length indicated are prohibited. It shows two circular length limit signs together side-by-side (one metric and one imperial).
  • Sign table — Schedule 3, Part 2, Item 26 on page 73 shows Diagram 629A. It shows a dual circular width limit sign.
  • Sign table — Schedule 3, Part 2, Item 27 on page 73 shows Diagram 629.2A. It shows a dual circular height limit sign.
  • Sign table — Schedule 12, Part 20, Item 6 on page 327 shows a dual triangular height limit sign.
  • Sign table — Schedule 12, Part 20, Item 33 on page 331 shows two circular length limit signs together (one metric and one imperial).
  • Sign table — Schedule 12, Part 20, Item 34 on page 331 shows a dual circular width limit sign.
  • Sign table — Schedule 12, Part 20, Item 35 on page 332 shows a dual circular height limit sign.
  • Sign table — Schedule 12, Part 28, Item 23 on page 363 shows Diagram 818.5. This is described as the location of a low bridge with indication of alternative route. It contains an inset image of a dual triangular height limit sign.
  • Sign table — Schedule 13, Part 6, Item 14 on page 386 shows Diagram 7243. This is described as a temporary road layout with lane restrictions. It contains an inset image of a dual circular width limit sign.

The Know Your Traffic Signs online manual still shows imperial-only vehicle dimension signs in a number of places. Drivers would still be expected to be familiar with the imperial-only versions because many still exists on the road network and it will take a few years for them all to be phased out and replaced with the dual-unit versions. The print and online versions of Know Your Traffic Signs will eventually need to be updated when imperial-only vehicle dimension signs no longer exist. However, the Signs for road works and temporary situations section on pages 130-132 should not show imperial-only width restriction roundels on road works signs. These signs are temporary and road contractors are no longer authorised to use the imperial-only width limit roundels on road works signs. The TSRGD 2016 states that they must use the dual-unit versions of these roundels on road works signs.

As the TSM instructs road contractors on signage, it is  important that the TSM reflects the current regulations in the TSRGD 2016. In several places, it does not. The TSM contains several references to imperial-only vehicle dimension signs, which are not authorised in TSRGD 2016. Accompanying text suggests that the metric units are optional and does not make clear that dual-unit circular and triangular width and height limit signs must be used. Likewise, it does not make clear that metric length limit signs must be shown alongside imperial length limit signs but suggests that the metric versions of these signs are optional. These discrepancies can be found on the following pages (using PDF page numbering, which counts the cover page as Page 1):

  • Pages 40-42 of TSM Chapter 3.
  • Page 34 of TSM Chapter 4.
  • Pages 40-41, 64, 71, 80, 121, 131, 152 and 154 of TSM Chapter 7.
  • Pages 99-100, 186, 188, 198, 206 and 214 of TSM Chapter 8 Part 1.

Ideally, the text around the images in Know Your Traffic Signs and TSM should also be updated to reflect the current regulations in TSRGD 2016 which mandate the use of dual units on new and replaced vehicle dimension signs. Presumably, lack of staff prevents this being done immediately for the online versions of these publications. Any forthcoming print versions of these publications should be updated to reflect the current regulations, but whether this happens remains to be seen.

This lack of co-ordination between the TSRGD 2016, TSM and Know Your Traffic Signs publications is an unfortunate consequence of the decision taken in 1972 not to proceed with the conversion to metric measures of UK road traffic signs, and it does the UK Government no credit. Perhaps it is an indication that our two-system measurement muddle has become a luxury the UK can no longer afford.


7 thoughts on “Lack of co-ordination between DfT publications”

  1. On top of the mental conversion to metric that people make when road signs are converted to metric (only!), there is the more obvious fact that I did not take sufficiently into account that converting road signs to metric only requires that metric signs be made the only legal signs on roads and Imperial signs become consequently illegal.

    Such a change will finally put a knife into the heart of ARM, BWMA, and anyone else who tries to shamelessly intimidate people into scuppering metric. And that day cannot come soon enough.


  2. I was interested to read the comment about temporary signs in roadworks, in the last few days I’ve been scratching my head at the relatively newly placed width restriction signs in road works on the M1 in Northamptonshire and Nottinghamshire and I know I’ve seen more in recent months on other roads in the East Midlands.

    It does strike me that one of the things Brexit has done is made people believe that they no longer need to comply with laws that they believe have been imposed on us by the EU and given the anti-EU theme generally used by the pro-Imperial camp it would hardly be surprising that road contractors would be caught up in this. Sadly there seems to be little or no compliance checking on this sort of thing at the best of times so it’s hard to see how there will be any movement in this field now for several years.


  3. @Alex Bailey:

    Stand-alone dual unit signs are supposed to be larger than normal so that all the numbers are at a readable size. It’s not obvious from these uncoordinated documents—and difficult without being a classics scholar given several days to unpick them all—whether sub-signs (signs within signs) are supposed or even allowed to do the same, so you would end up with dual temporary signs where both measurements are illegible at speed. So many layers of bodging just to avoid getting rid of the imperial altogether… Is there a single HGV operator still licensed who wants or needs it to be there?

    DFT send out circulars to highway authorities, which are probably another source of contradictory cruft. These notionally advise staff when deprecated signs are about to lose their legal status and have to be removed, instructing them to change all their height/ width signs to dual within 2 years from 2016, etc. Assuming everybody reads and acts on them, of course!

    My conspiracy theory is that UK highways illuminati have tried to regress to pre-Worboys signage via the back door. Hence red background for ‘CYCLE TRACK CLOSED’, inter alia. A blue rectangle for ‘CYCLISTS DISMOUNT’ only makes sense in those terms and ‘cycling prohibited’ isn’t a blanket-authorised form of words since the 1950s & probably deeply illegal with that roundel. Might also explain why they are so reluctant to allow metric and keep open a possible switch back to imperial-only on regulatory signs. Likewise the zealous obstruction of metric distances for supplementary plates and direction signs. It would only have taken a few well-placed individuals to do this and then rely on the institutional complacency and well-entrenched incompetence to keep it in place for fifty plus years.


  4. @Mark Williams

    Having spoken to the Highways Agency in the past about these signs and their use (the recommendation to use dual metric/imperial has been in place for years before they became mandatory) I’ve heard all the excuses in the book. One of which was that the dual-unit signs have to be so large that they are more difficult and dangerous for contractors to move while working on motorways!

    In any case I was interested to see that the signage that was put in place on the M6 around Coventry that originally had a mix of dual-unit and imperial-only width restrictions has since been replaced with dual-unit signs!


  5. @Alex Bailey

    In your contact with the Highway Agency, have you ever inquired why metric speed and distance signs are forbidden? What reason do they have for not allowing them? I understand they may have a valid reason for not wanting to change, but I don’t understand why they won’t even allow metric speed and distance signs on the road.

    The problem they have created is that there are those that want metric signs and when they do appear a terrorist group runs around changing them.

    They need to change their policy in two ways, first they need to make metric signs completely legal and they need to make it a criminal act to deface or amend a road sign.


  6. @Daniel Jackson

    My conversations with the Highways Agency (HA) have been strictly limited to their interpretation and implementation of the rules handed down by the Department of Transport and published in the Road Signs Manual.

    The HA are merely a branch of the government responsible for managing the major roads in the UK and, as far as I’m aware, probably have little or no influence in policy making.


  7. @Alex Bailey:

    LOL. ‘Won’t someone please think of the wind loading (in newtons)’ 😁? Only a few weeks ago they were replacing lots of large MS4 on the M1—4.4 m × 3.2 m, 730 kg, ≤2.7 kW—for no reason evident to me as a non-insider. HA doesn’t seem too bothered about the workers when it is something the bosses want to happen.

    Of course, the metric-only height sign fits on a standard size roundel with not only full sized numbers but also extra large number of whole metres and decimal marker. A metric-only width sign would, too, with the ‘m’ cheekily split onto a second [overlapping] line as the Bangladeshi version does: diagram A15, UK diameters (450, 600, 750 and 900) mm, 10 % wide border, Transport Heavy typeface, 50° isosceles triangles. Excuses void!

    @Daniel Jackson:

    HA have more policy influence over DFT than either care to admit. When they put up hundreds of illegal variable motor speed limit signs at an eye-watering cost which the loophole lawyers then discovered could not be enforced; an amendment to the regulations was hurriedly drafted, passed and enacted within a couple of years to retrospectively legalise them. Lightning fast considering DFT’s usual lethargy! If HA had insisted on metric-only lane restrictions to keep the sign size down instead of ignoring dual unit ‘recommendations’ for 15 years until the deadline, it almost certainly would have been done that way nationwide. The compulsory addition of metric to height signs was the result of forceful demands by Network Rail, not DFT benevolence or UKMA campaigning (sorry!) and applies everywhere.

    HA could agitate decisively for metric speed and distance if they chose to. All of the HGVs making up most of the traffic on their network have metric tachographs and we’re already well past the point where the majority of the population received only metric education. DFT know this, which is why they’ve had to abandon most of their previous excuses and are left with a pathetic ‘we can’t afford it’ and ‘we’re incapable of project managing it’.


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