Successive UK governments have retained imperial units exclusively for distance and speed on road traffic signs. Ronnie Cohen argues that, as a result, we have been unable to take advantage of universal unit symbols, a feature of the metric system but not of imperial.
A consequence of the retention of imperial is the use of unnecessarily large and verbose traffic signs, which could otherwise be so much smaller, simpler, cheaper and more legible at speed. The measurement muddle also leads to many variants for common traffic signs, including some unofficial ones not found in the Traffic Signs Regulations and General Directions (TSRGD). Here are some examples of verbose signs where simpler pictograms and symbols could be used instead:
There are standard, non-textual, signs for all three signs shown above. The first image shows an odd number of yards, which is equivalent to 250 metres. The second image could have been shown with a roundel with the number 30 on it. The last one appears just before the junction with Finchley Road. There is a pictogram for that too. To what extent does the diversity of variant signs encourage the erection of large verbose signs?
The problem of verbose signs is particularly evident in Wales where textual signs must be bilingual. Here are a few examples:
Distance plates could show “800 m” and “500 m” with arrows added where necessary. How much would that saved if that approach was taken across the country? As we saw in a previous article, the limitation in the TSRGD of imperial for distance signs is out of step with the private sector where private distance signs to car parks, attractions, restaurants and business premises often show metres rather than yards.
There are other issues with the use of verbose signs. Some describe new features of roads in particular locations:
Why aren’t pictograms used instead of these large signs? Given that the life span of a typical road sign is 10 years, is it ever a good idea to describe something on the roads as “new” on a road sign? After a while, that road feature will no longer be “new”.
Some verbose signs are probably unnecessary. Drivers are expected to know what road markings mean so why does Barnet Council find it necessary to attach several signs like this one to the railings by the same zigzag road markings? Perhaps garish signs are seen as an alternative to enforcement.
Other textual signs used on British roads are sometimes surprisingly large. Pictograms could often be used as an alternative, and some signs are unnecessary. Here are some examples of large textual signs:
The major issues with the use of verbose signs are that they are large, expensive, often illegible at speed and unsightly. Remember the Department for Transport (DfT) estimated in 2005 that the average cost of converting a sign from imperial to metric was about £1400. Some are unnecessary and some could be replaced with pictograms. Metric versions of verbose signs that show measurement units could be so much simpler, smaller, clearer and cheaper.
Incidentally, the Welsh translation on the bilingual sign is incorrect – another reason for using pictograms and internationally recognised symbols whenever possible. At least, the sign at the ford refers to depths in an internationally understood measure.
Successive governments, in refusing to convert road traffic signs to metric, have often given cost as a reason. The DfT, in justification, has said, “The significant costs involved for the UK in changing the measurements used on signs, replacing signs, providing safety and publicity material and the consequential costs for businesses and other organisations would far exceed any benefits ….” This statement relies partly on grossly inflated and discredited cost estimates for the conversion of road signs, and takes no account of consequent savings. I have written about DfT cost estimates in a previous Metric Views article: http://metricviews.org.uk/2012/05/dft-cost-claims-busted/.
How much money is spent on verbose or unnecessarily large signs when these could be smaller, simpler and cheaper if metric units were permitted and pictograms adopted? As long as the units on the signs are clear, that should not be a problem. The USA, the only other developed country that uses non-metric units on its road signs, allows metric units as an alternative. By changing the TSRGD to permit metric units for road traffic signs showing distance, the phasing out imperial units on British roads could begin at no extra cost and without “diverting resources from higher priority areas” – another favourite phrase of the DfT and its political masters.
Speed signs are a special case as they are safety-critical and would need to be replaced quickly with a full education campaign to inform drivers about the changes. The Republic of Ireland did this in 2005 and showed how it can be done safely and for a small fraction of the DfT’s estimated cost.
You can find examples of how traffic signs can be so much simpler and more legible in metric at http://www.ukma.org.uk/gallery.
You can find more information about the issues with vehicle dimension signs in the UK at http://www.ukma.org.uk/sites/default/files/ukma-dimension-signs-review-2014-05.pdf.
You can find more information about how metric signs could improve the quality of road signage in the UK at http://www.ukma.org.uk/sites/default/files/Traffic_Signs.pdf.