A Freedom of Information response from the Department for Transport reveals that it has done no research on the general public’s familiarity of road sign units. The DfT once used the lack of metric education as an argument against the metrication of road signs but has never seen the lack of familiarity with imperial units as a problem with its current use of imperial road signs.
On 31 January 2022, I made a Freedom of Information request at the DfT asking:
“What research has the DfT done or sought from other sources to find out how well the general public understands miles, yards, feet, inches, kilometres, metres and other measurements used on British roads?”
On 28 February 2022, the DfT sent me the following reply:
“Following a thorough search of our paper and electronic records, I have established that the information you requested is not held by this Department.
I can confirm that there has been no research done by the Department, or sought from other sources, on how well the general public understands miles, yards, feet, inches, kilometres, metres and other measurements used on British roads.”
The imperial system has not been taught as a separate measurement system in British schools for decades. In the Department for Education’s statutory guidance for mathematics programmes of study in the National Curriculum in England, there is a Measurement section that states what pupils are expected to be taught. One of the items in the list under this section states that pupils should be taught to “understand and use approximate equivalences between metric units and common imperial units such as inches, pounds and pints”. In other words, only conversion factors between common imperial units and metric units are taught. Apart from that, it is metric all the way.
Despite the fact that relationships between different imperial units are not taught in British schools and have not been taught for decades, the DfT still expects young drivers to be familiar with the miles, fractions of miles, yards, feet and inches used on British road signs. The DfT has never seen this as an issue for imperial usage on British roads.
However, the DfT once claimed 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). Subsequently, it was suggested that conversion might be considered when a majority of drivers had received metric education.
The UK has already passed this point because metric units have been mandatory in state schools since 1974, and therefore all drivers who were born after 1964 will have received their secondary education using metric units. In any case, evidence from other countries’ changeovers demonstrates that such “confusion” is not a significant problem.
Why did the DfT see this as an issue for metric units but never for imperial units? The DfT does not mind if you do not know the number of inches in a foot or the number of yards in a mile. This information does not appear in DfT publications.
In 2013, the UKMA commissioned YouGov to do a survey to find out the public’s understanding of the imperial and metric systems. This survey showed that the public were more familiar with the metric system. It revealed that 76% of respondents were unable to answer correctly how many yards there are in a mile and 43% could not say how many metres there are in a kilometre.
Despite the UKMA findings that over three-quarters did not know the number of yards in a mile, despite the widespread usage of both units on British roads, the DfT has never seen this as an issue. So why did the DfT see unfamiliarity with metric units as an issue despite the fact that far more knew the number of metres in a kilometre? How could lack of education be an obstacle to the metrication of British road signs but not with the current imperial road signs?