Ronnie Cohen reports on his recent correspondence with the UK Department for Transport (DfT).
I recently asked the DfT what measurement units they expect drivers on British roads to be familiar with. It responded (ref. GT51/2/2/F0014554), saying “The answer to your question is that we would expect drivers, for the task of driving on British roads, to be familiar with miles, yards, feet, inches, metres and tonnes.” (my emphasis). I also asked it to supply me with any relevant documentation about what drivers are expected to know about measurement units, especially the ones that appear on traffic signs, and was told that this information can be found in the Highway Code and Know Your Traffic Signs and that both can be accessed from the following link:
What a contrast this is to the claim that drivers who have not received metric education at school would be confused by a change to metric units (Parliamentary Written Answer, 11 July 2002, Hansard, Col 1116w). In a previous Metric Views article, I asked the DfT what evidence it had for this claim and it admitted that it had none (see https://metricviews.org.uk/2013/05/dft-guilty-of-making-unfounded-claims/).
Metres are used throughout The Official Highway Code, sometimes on their own. For example, the 2015 edition of the Highway Code, an official DfT publication, states on page 29, “You MUST be able to read a vehicle number plate, in good daylight, from a distance of 20 metres (or 20.5 metres where the old style number plate is used).”. Metres appear on their own in other places in the 2015 edition of the Highway Code:
- Page 32 shows a table with an entry for a “child from 3rd birthday up to 1.35 metres in height”.
- Page 40 of the Highway Code shows a table on speed limits with an entry for “buses, coaches and minibuses (not exceeding 12 metres in overall length)”.
- Page 42 tells drivers, “If you have to stop in a tunnel, leave at least a 5-metre gap between you and the vehicle in front.”.
- Page 101 tells drivers, “Tramway overhead wires are normally 5.8 metres above any carriageway, but can be lower.” and “Where overhead wires are set lower than 5.8 metres, these will be indicated by height clearance markings – similar to ‘low bridge’ signs.”.
- Page 117 contains a couple of sentences with metres only. Under the heading “Large goods vehicle rear markings”, it states, “The vertical markings are also required to be fitted to builders’ skips placed in the road, commercial vehicles or combinations longer than 13 metres (optional on combinations between 11 and 13 metres)”. Under the heading “Projection markers”, it states, “Both required when load or equipment (eg crane jib) overhangs front or rear by more than two metres.”.
Metres also appear on their own in a few places in Know Your Traffic Signs:
- Page 87 tells drivers, “Marker posts, located at the back of the hard shoulder at 100 metre intervals, show the direction to the nearest telephone (housed in an orange box).”
- Page 88 tells drivers, “Some motorways may have special chevron markings in the centre of traffic lanes. These are spaced 40 metres apart, …”
- Page 127 tells drivers, “Drivers should stop at the broken ‘give way’ line (about 1 metre before the crossing) when pedestrians are using the crossing.”
Despite the fact that the DfT expects drivers to be familiar with metres, as we can clearly see in the Highway Code and in Know Your Traffic Signs, they have never allowed distance signs to display metres. Since 1981, the DfT have allowed metres to be displayed on vehicle dimension signs but only alongside feet and inches, never without the imperial conversion.
So why are the Government and the DfT so opposed to the use of metres on distance signs and why do they still insist that vehicle dimension signs must display feet and inches when metres would be enough? Why is there a disconnection between the measurement units that appear in official DfT publications and the measurement units that appear on official road signs? The fact that they do not even allow distances to be expressed in metres in the Traffic Signs Regulations and General Directions 2016 surely has nothing to do with cost. The use of yards for distance signs could be phased out over several years and replaced with ones showing metres when the signs are due to be replaced with no additional public expenditure. Alas, the political will to do so is absent. The UK is virtually unique in the whole world for not allowing metric units on almost any road signs. This is unlike the USA, the only other major country that uses non-metric road signs, which allows them as an alternative.
Successive governments and the DfT apparently have had an unwritten policy for many years of using metric units for professionals and imperial units for general road users on British roads. An example of this can be seen with its instructions to road contractors to place road works signs at intervals of 100 metres but display the signs in multiples of 100 yards. How illogical is that? Only the DfT insists on such nonsense. Yet, the DfT expects drivers to be familiar with both systems of measurement in the Highway Code!