Eight years after the Traffic Signs Regulations and General Directions (TSRGD) were updated to require all new vehicle restriction signs to show vehicle width and height restrictions in both metric and imperial units, the Department for Transport’s Traffic Signs Manual (TSM) has still not been fully updated to take account of the fact that new imperial-only vehicle restriction signs are no longer authorised.
Whilst most other chapters of the Traffic Signs Manual have been updated since 2016, Chapter 8 Part 1 has not been updated since 2009. It includes diagrams for both imperial-only width and imperial-only height restriction signs for use in road works and temporary situations – signs which were legal back in 2009, but have not been authorised for new sign installations since 2016.
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Vehicle restriction signs included in the current TSM – Chapter 8 Part 1, page 98
The Traffic Signs Manual contains guidance for traffic authorities on the use of traffic signs and road markings. By failing to fully update it in a timely manner, the Department for Transport stands open to the accusation that they have been promoting the use of unauthorised imperial-only road signs for the last 8 years.
click on the image to access the pdf
The diagram for weight restriction signs is also obsolete as it includes the now unauthorised upper case “T” symbol to represent tonne. The diagram for this sign was corrected to show the lower case “t” in the 2011 amendment to the TSRGD.
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| 629A | 629.2A | 622.1A |
Vehicle restriction signs in the current TSRGD
Whilst diagrams in publications for the general public, such as The Highway Code and Know Your Traffic Signs, were updated long ago, it is inexplicable that guidance for authorities that install road signs should not also have been updated.
UKMA would be interested to hear from readers of any cases that they might be aware of in their area where imperial-only restriction signs have been installed since 2016, and would encourage writing to the relevant highway authority asking for such signs to be replaced with legal dual-unit signs in order to avoid possible legal ramifications.
Editor: For an update on this issue see:
Metric Views 
the upper-case “T” is the symbol for teslas, a unit of measure that of magnetic fields. The only vehicle that I am aware of that might produce a field of 7.5 teslas is a tardis, but to date I have yet to see an authoritative measurement of this quantity.
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The DFT is not my idea of a well-organized department. I remember the debacle over the latest Highway Code. Several controversal changes were announced in the media, but we had to wait many months for the booklet itself to appear in the book shops so that we could see for ourselves.
Could it be that the Traffic Signs Manual has been updated, but the copy on the Government web site has not been?
There are still plenty of imperial-only height and width signs around, but I don’t know of any that have been installed recently. I do however know of a couple of height restriction signs showing metric only. (I am not planning to snitch on the authority concerned.)
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Metricmac,
Is there a possibility that the metric only signs you have encountered may have been purchased from outside of England. After-all, they are the same sign format. It may be that the cost of the sign is much cheaper elsewhere, so those signs would be metric only, thus the reason the ones you encountered are metric only.
One has to wonder if an English company that has been producing these signs for decades in FFU would suddenly produce a small amount of signs in metric only. The company may be aware of the law and thus refuse to produce metric only signs. So, those that want them have to purchase them from a company in a metric country.
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@Daniel
Metric-only height restriction signs have been around since 1981. They could only be legally installed alongside an equivalent imperial sign.
The roundel sign was de-authorised in 1994, when it was replaced by a dual-unit roundel. The metric-only warning triangle sign was de-authorised only as recently as 2016.
See:
https://metrication.uk/transport/roads/vehicle-restriction-signs/#1981
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@Daniel: I visited teh sites of a number of UK road sign manufacturers. Most of their signs are metric-compliant, though there are circumstancs where metric and imperial signs should be used side-by-side and the manufacturers will supply either separately. Here is a list of manufacturers that I found:
https://startsafety.uk/collections/post-mounted-signs
https://hirstsigns.co.uk/product-category/road-traffic-signs/
https://morelock.co.uk/standard-tsrgd-signs/
https://www.road-signs.uk.com/Road_Signs/Width_or_Height_Restriction.html
https://roadsignsdirect.co.uk/road-signs
All of the suppliers have “Free TExt” signs.
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