By international agreement under the auspices of the United Nations, new road signs showing pedestrian escape routes with distances were adopted for international use in tunnels in 2003, providing a common design for use in all countries to improve evacuation in the event of a tunnel incident. These new signs added the distance in metres to the nearest exit, as illustrated in the updated Vienna Convention on Road Signs and Signals:

In the UK, the Department for Transport (DfT) noted this advance, but decided that new signs using obsolete imperial units should be erected in tunnels across the UK, regardless of whether young people or visitors to this country may need to be evacuated from a tunnel, and heedless of government guidance that metric units are the primary system of units in the UK.

New signs are being installed by highway authorities in tunnels across the UK, including in London, where Transport for London (TfL) are refurbishing road tunnels with new signs showing the distance only in yards (and to the nearest yard!), as shown in this picture taken in the Rotherhithe Tunnel:

Meanwhile, TfL re-opened the refurbished East London line last month, whose tunnels pass below the Rotherhithe road tunnel.

This being the UK, the same standards do not apply in road and rail tunnels. New escape signs have also been installed by TfL within the rail tunnel adjoining the road tunnel:

Unlike the road tunnel, the rail tunnel is signed in metres, meaning any visitors are able to judge the distance to the emergency escape. Full marks to the rail authorities for using units all potential users will understand, but it highlights the mess that the UK is in when adjacent tunnels, one road and one rail, under control of the same authority, provide critical passenger safety information in different units and expect users to be able to understand both.

Sadly, other backward steps have been made within the rail tunnel. Line distances on the London Underground network changed to kilometres as long ago as 1972, but with the conversion of the East London line to National Rail standards, new mile and chain marker posts have replaced the metric signs which have stood for nearly 40 years. The new yellow sign below indicates the 3 ¾ mile mark:

At least these signs are not for public consumption!

Hugo Vickers, chairman of the Jubilee Walkway Trust, told the Evening Standard that “as soon as we at the Jubilee Walkway Trust heard that the Olympic Games would take place in London in 2012, the same year as the Diamond Jubilee, we dreamed up a new route for London, 60 kilometres — one for every year of the Queen’s reign — to help people walk to the main Olympic sites. It will also leave a lasting memorial to the Diamond Jubilee.”

The route will take in many of central London’s main sights as well as the Olympic Park at Stratford, and sections of the Thames Path, and will be marked with 60 illuminated beacons.

Sadly the 60 kilometres of the new trail will not actually be signed as such despite walkers’ reliance on kilometre-based Ordnance Survey mapping. This is due to the insistence of the Department for Transport (DfT) that, despite more than 30 years of metric teaching in schools, the British are not considered to be ready to see signs in metres and kilometres.

While some enlightened authorities erect informal signs in kilometres (understandable to British walkers and tourists alike) while others prefer to use signs that visitors can’t understand, the DfT is introducing yet a third system of hours and minutes for walking and cycling signs – which are of limited value to anybody not walking or cycling at the assumed speed (see this article).

Many others, knowing that foreign visitors are not familiar with imperial units, that journey times are useless for anyone slower or faster than the assumed speed, and that metric units are not permitted on official signs, choose to do without distances (or times) at all.

So two systems are permitted by the DfT, but not the one which is most readily understood by those who need to follow them.

The Select Committee’s report can be read at this link.  The background is that the Second EU Driving Test Directive (91/439/EEC) requires Member States’ own driving tests to include an emergency stop at 50 km/h (which is the standard speed limit for urban areas throughout Europe – except, of course, in the UK, where the speed limit is 30 miles per hour).  However, 30 mph equates to 48 km/h, which is a lower speed than that required for the driving test. Consequently it would have been illegal to conduct the motor cycle driving test on 30 mph roads in urban areas in the UK – as has been the practice in the past.  So how could the DfT solve this problem?

There would appear to have been (at least) three possibilities:

• Negotiate an exception (derogation) to the Directive, so that the UK test could be conducted at 30 mph.
• Build special off-road testing stations, where speeds above 30 mph could be permitted – at a cost of £71 million.
• Raise the UK’s default urban speed limit to 50 km/h (and convert other mph speed limits to the appropriate km/h value).  This would have entailed amending approximately 200 000 speed limit signs at a cost of ca £20 million¹.

With regard to the first option, we can do no better than quote the Select Committee report verbatim:

“It is difficult to see why the Government failed to obtain a derogation from the 50 km/h speed requirement for certain elements of the Module 1 test. Testing riders at a speed which exceeds the standard limit in built-up areas is both inconvenient and confusing for candidates. Requiring test candidates to drive according to a scale of measurement not widely used in the UK is bizarre……. It is unacceptable that the Minister was unable to offer any satisfactory explanation for the Government’s decision not to seek a derogation.”

It may well be that, as was suggested by some witnesses who gave evidence to the Committee, the DfT wanted to build these testing stations anyway – for reasons unconnected with speed limits.  On this view, it was convenient to be able to blame the EU for imposing an unnecessary cost on the long-suffering British taxpayer.  The Committee added “It is tempting to conclude that other priorities may have coloured the Government’s decision to implement [test centres] in the UK.”

The third option -  bringing the UK’s speed limits into line with those elsewhere in Europe –  does not seem to have been even considered by the DfT – nor, for that matter, by the Select Committee or its advisers and witnesses. Yet it obviously would have been a far cheaper solution than building 66 testing stations.  This failure to consider an obvious solution illustrates the imperialist, anti-metric mindset of those in charge of the DfT.  The appearance is given, yet again, that the DfT is prepared to waste large sums of taxpayers’ money rather than admit that the changeover to metric road signs is inevitable, and that the longer it is postponed, the more it will cost.

______________________________________________________________

¹UKMA estimate based on the actual unit cost of the Irish changeover in 2005 (i.e. £100 per sign) applied to an updated DfT estimate of the number of speed limit signs.  See also paragraphs 6.4 to 6.16 of “Metric signs ahead”, which can be downloaded at this link.

A summary of the case for converting the UK’s road signs can also be read on the UKMA website at http://www.ukma.org.uk/Campaign/policy/transport.aspx

Ironically, the proposal is one of a number of changes actually intended to align motorway speed limits with commercial vehicle speed limiter settings.

Speed limiters are required by law to be fitted to all new heavy goods vehicles (HGVs), and passenger carrying vehicles (PCVs). 90 km/h is the setting used for all HGVs over 3.5 t, and 100 km/h is the setting for all PCVs capable of carrying more than 8 passengers.

In recent years, as older vehicles have gradually been replaced by newer ones fitted with speed limiters, the de facto commercial vehicle motorway speed limit has become 90 km/h for HGVs, and 100 km/h for coaches and buses. As a consequence, it obviously makes sense to review commercial vehicle motorway speed limits and align them with corresponding speed limiter settings.

Yet, rather than opting for the obvious solution of setting commercial vehicle motorway speed limits equal to their corresponding speed limiter settings, the DfT has proposed rounding up to the nearest 5 mph. This means that all commercial vehicles will have motorway speed limits higher than their speed limiter settings. In their consultation document they state,

“it would be unrealistic to align the relevant speed limits exactly with speed limiter settings”.

Presumably, the option of setting speed limits in km/h, the same units that define speed limiter settings, has been overlooked.

Whilst it would be undesirable to have a mix of mph and km/h speed limit signs on our roads, the fact that speed limits for commercial vehicles are not signed means that there is no good reason why motorway speed limits for HGVs and PCVs cannot be defined in km/h, as speed limiter settings already are.

Also, as speedometers are required to show speeds in km/h, as well as mph, drivers of vehicles not fitted with speed limiters should have no problem complying with speed limits in km/h. The ideal solution to the DfT’s conundrum is therefore perfectly practical – commercial vehicle motorway speed limits can be aligned exactly with speed limiter settings.

Of course, having speed limiter settings defined in km/h, as is required by international regulations, means that regardless of how the DfT eventually choose to define new HGV and PCV speed limits, the reality will remain that two different systems of speed measurement are being used on our roads – a situation that can only be satisfactorily resolved by switching to km/h speed limits for all vehicles.

We would therefore recommend that the DfT should as soon as possible initiate a comprehensive plan to complete the switchover to metric units for all road traffic purposes – something that was originally scheduled for 1973, but was postponed in 1970 without a new date being set.

Consultation

The Department for Transport is inviting comment to their speed limit proposals in a public consultation.

The UK Metric Association’s consultation response can be viewed at the following link:
http://ukma.org.uk/docs/rtc/speedlimits201003.pdf

The consultation remains open until 27 April 2010.

References

Consultation on Heavy Goods Vehicle and Passenger Carrying Vehicle motorway speed limits.
http://www.dft.gov.uk/consultations/open/2010-06/

Speed Limiter Legislation

The Road Vehicles (Construction and Use) (Amendment) (No.2) Regulations 2004
http://www.opsi.gov.uk/si/si2004/20042102.htm
The Road Vehicles (Construction and Use) (Amendment) (No.5) Regulations 2005
http://www.opsi.gov.uk/si/si2005/20053170.htm

House of Commons - Roads (Speed Limit Signs)
9 December 1970 vol 808 cc417-8
http://hansard.millbanksystems.com/commons/1970/dec/09/roads-speed-limit-signs

UKMA’s leaflet Traffic Signs 2.0, summarising the case for metric signs, can be downloaded by clicking on this link.  Alternatively, free printed copies can be obtained by e-mailing secretary@metric.org.uk

This is the press release issued by UKMA on 26 March.

LONDON, 26 March 2010. Transport for London (TfL) was today criticised by the UK Metric Association (UKMA) for bungling the erection of new signs at the Rotherhithe tunnel, including banning all vehicles over 33 inches long from using the tunnel.

Warning signs at low bridges and tunnels are normally signed in metres as well as feet, following Department for Transport (DfT) advice to reduce the number of large vehicles getting stuck and causing delays, particularly foreign goods vehicles.

However, TfL recently spent over £6,000 on new restriction signs at the tunnel entrances, but failed to add metres to many of the signs at the southern end, despite increasing problems with over-height vehicles at London’s river crossings (see pictures below).

Even more bizarrely, not only is the 10 metre length restriction still not posted in metres, but new signs have been erected which ban all vehicles longer than 33 inches from using the tunnel, instead of 33 feet.

UKMA Chairman Robin Paice said, “It beggars belief that new height restriction signs have been installed at the Rotherhithe tunnel without following long-standing national guidance and including metres, which could have been added at no extra cost and reduced the delays incurred whenever over-height vehicles try to enter the tunnel.”

“At the northern end, metres are included on the height and width signs, but not on the length restriction. Even those erecting the signs clearly don’t understand the imperial units very well, having signed the 10 metre length restriction as 33 inches!  If the government allowed the simple 10 m restriction to be added it is highly unlikely that the wrong measurement would have been posted as it would have been quite obvious that the signs were wrong.”

In 2009 the Department for Transport announced a proposal that the current recommendation that metres should be included on height restriction signs should become mandatory – meaning that the new signs will need to be replaced again.

When asked what plans TfL  had to implement the DfT’s 1990s advice to add metres to height restrictions, TfL replied that “currently there is no programme to replace any signs which remain legal. If the use of metric becomes mandatory, a cost effective programme will be put in place to update all of the non-compliant signs.”

Robin Paice responds, “It is extraordinary that rather than implement the DfT’s guidance at no cost when new signs are erected, TfL would rather waste money on new signs which will shortly be obsolete, and which increase the risk of accidents on London’s main roads.”

UKMA is calling on all highway authorities to update their vehicle restriction signs to include metres in accordance with DfT advice at the earliest opportunity, rather than waiting for the deadline for mandatory replacement of imperial-only signs to approach.

ANNEX 1: DEPARTMENT FOR TRANSPORT GUIDANCE

Traffic Signs Manual Chapter 3

Department for Transport, 2008

http://www.dft.gov.uk/pgr/roads/tss/tsmanual/tsmchapter3.pdf

On width signs (para 5.36):

“It is recommended that this sign [metric and imperial] is used in preference to the sign to diagram 629 [imperial-only signs].”

On length signs (para 5.38):

“It is recommended that both the imperial and metric sign should be used wherever practicable.”

On height signs (para 5.42):

“It is recommended that the sign to diagram 629.2A [metric and imperial] is used in preference to the imperial-only sign.”

Draft Traffic Signs (Amendment) Regulations and General Directions (TSRGD) 2010

Department for Transport, September 2009

http://www.dft.gov.uk/consultations/closed/trafficsignsamendmentregs/consultation.pdf

Draft changes to the regulations to come into force in Spring 2010:

“Width and Height Restrictions

2. We are making changes to require both metric and imperial triangular warning signs to be displayed to give warnings of restricted headroom, with the upgrade being complete in four years’ time. Using the imperial sign on its own will no longer be permitted.

3. We are making similar changes to require both metric and imperial measurements to be displayed on all width and height restriction roundel signs, with the upgrade being complete in four years’ time. The current imperial-only signs shown in diagrams 629 and 629.2 will be withdrawn.”

ANNEX 2: PHOTOGRAPHS ATTACHED

All photos by UKMA. News organisations are free to use any of these photographs to accompany this story, with or without credit to UKMA (but not credited to others).

Picture 1: New panel at Rotherhithe tunnel with height in feet only

Picture 2: New panel at Rotherhithe tunnel with height and width in feet only

Picture 3: 10 metre length restriction signed as 33 inches (or around one metre)

Picture 4: Close-up of 10 metre length restriction signed as 33 inches

Although the Department for Transport (DfT) has recently proposed the replacement of imperial-only height and width restriction signs (roundels and warning triangles) with dual metric/imperial signs within 4 years, it has furiously denied that this proposal is part of a comprehensive plan for converting the UK’s road signs. A DfT spokesperson is quoted as saying that the proposal was “absolutely not the thin end of the wedge” and that there were no plans at all to use kilometres, rather than miles, on distance signs, adding: “This is a specific solution to a specific problem” (i.e. a disproportionate number of damaging bridge strikes by foreign lorries).

In its refusal to accept the inevitability of metric road signs the DfT is increasingly at odds with other Government Departments – and indeed with stated Government policy on metrication.  Consider the following quotations:

(a)  “As you will be aware, all Governments since 1965 have adopted the policy that the United Kingdom should – in stages – switch from imperial to metric units of measurement for an ever-increasing range of uses.”

(b)  “The Government’s longstanding policy in relation to units of measurement is to move to full metrication in time but at a pace that recognizes that a significant proportion of consumers are still more comfortable with using imperial units.”

Quotation (a) is from a letter dated 15 September 2004 from former Prime Minister, Tony Blair, to UKMA’s patron, the former Chancellor and Foreign Secretary, Lord Howe.  Quotation (b) is from a letter dated 7 December 2008 from the Minister for Science, Lord Drayson, to the Chairman of the UK Metric Association.

Even more recently (25 February 2010),  the junior Minister of Health, Baroness Thornton, said in the House of Lords that she “absolutely agreed” that it is time to clear up the “very British mess”.  All these statements make it clear that full metrication is the ultimate goal, and none of them adds  “Oh, by the way, we didn’t mean to include road signs”.

Indeed the Transport Department itself appeared for many years to accept that metric conversion was inevitable – while endeavouring to postpone the date for as long as possible. For example in July 2002, in answer to a Parliamentary Question asking what plans there were “to replace miles with kilometres on traffic signs used to indicate speed limits and distances”, the then Transport Minister, David Jamieson, responded:

“Although many drivers are familiar with metric units, it would not be appropriate to fix a date for converting speed limit and distance signs while there is still likely to be a significant proportion of drivers for whom the change could be potentially confusing.” (Hansard, 11 July 2002, Col. 1116w).

The clear inference to be drawn from this somewhat ambivalent reply is that, when there is no longer a “significant” proportion of such confused drivers, then it would be appropriate to fix a date for conversion.

Since then, the DfT has hardened its stance against conversion.  As it is now likely that the majority of UK drivers were born after 1964 (and would therefore have received their secondary education in metric units), the argument about “confused “ drivers has lost most of whatever validity it had. So the DfT have come up with a new argument: cost. They claimed that the cost of converting half a million signs, estimated at £680 - 760 million (ca. £1400/sign) would be disproportionate to the benefits for transport and is not a priority for scarce resources.

UKMA believes that the costs have been grossly exaggerated – possibly deliberately. It is palpably absurd to claim that the average cost of amending or replacing road signs is £1400 per sign. UKMA’s “most probable” estimate was £160 per sign, and this is supported by independent data. [See this link for details]. The DfT is guilty of “shroud waving” in order to protect its budget.

Even if the DfT cost estimate were credible, it is still only a tiny proportion of total transport expenditure (£21.5 billions in 2007/08), and is capable of being spread over several years and partially absorbed within existing budgets.

All other sectors of the economy have already absorbed the costs of change within their own budgets. Manufacturing industries have retooled their factories, retailers have invested in new scales and retrained their staff, schools have redesigned syllabuses and purchased new textbooks – yet the DfT has continually sought to postpone the inevitable – thereby actually increasing the eventual cost (as any additional new imperial signs will have to be amended or replaced). An example of this DfT waste is the decision to launch a programme of reduced speed limits in residential areas while still denoting those speed limits in miles rather than kilometres per hour. Thus, in 2007/08, as a Freedom of Information request has revealed,  the city of Portsmouth installed 3128 “20 mph” signs (on new posts) at a cost of £313 000 (average cost £100), much of which will have to be duplicated when they are eventually changed to “30 km/h”.

Indeed the DfT appears to believe that it can stand aside indefinitely from Government policy on measurement units and that road signs will always be a “stand alone” system, separate from the rest of society.  In doing so, the DfT is the last major obstacle to the achievement of a single, rational system of weights and measures in the UK.

As long as road signage and speed limits remain imperial, it will be difficult for many people to shed the habit of thinking of distances in terms of miles, yards, feet and inches or of speeds in terms of miles per hour.  This lack of facility to think in terms of metres, kilometres and kilometres per hour then spills over to other walks of life.  Weather forecasters feel obliged to translate windspeeds from metres per second or kilometres per hour to the more familiar miles per hour.  Journalists, fearing that their readers will not understand metres, feel bound to translate foreign news stories from metres to feet (or yards).  DIY shops and garden centres feel bound to give product descriptions and instructions in feet and inches.  Publishers of road maps and atlases fail to take full advantage of the kilometre-based National Grid for identifying locations.

As long as this imperial anomaly persists, many people will have difficulty in making the change in other fields and in “thinking metric”.  It is therefore essential to the achievement of the metric changeover in other fields (such as news reporting, weather forecasting, advertising, product description and maps and atlases) that road signage is brought into line.  It is untenable that it can continue to be a “stand alone” system.

In the national interest, the DfT should fall in line with Government policy.

One further Government pronouncement is worth quoting. This is from the 1972 White Paper (paragraph 107):

“The present system for showing speed limits and other road signs is unlikely to be changed for a long time to come.”

The author of that statement was right: 38 years later they haven’t been changed. One wonders how much longer they think they need.

“Now navigation.  There are still lots of aircraft that are flown around the world that do not have sophisticated navigation aids and pilots need simple ways of mentally calculating navigational requirements.  One of the most common is based on the fact that 1 radian (the angle at the centre of a circle that is subtended by an arc equal to the radius) is approximately 60 degrees.  The navigational trick is known as the “one in sixty rule.”

Very simply put, if a pilot is 1 mile off track after 60 miles then the  error is 1 degree which gives a simple way of calculating the change needed to take out the error..  As an example, if the distance to be flown is 120 miles and after 60 miles the pilot identifies that he is 1 mile off track then he needs to turn 2 degrees to make good his destination (one to fly parallel to his track and one to close the destination).   Now this will work for any unit of measurement.  One banana off after 60 bananas is still an error of 1 degree.   The crunch it seems to me is that, as I understand it, the internationally agreed global positioning system is still based on latitude and longitude (all the GPS systems I have dealt with start with a very sophisticated lat/long model of the earth) and the angle subtended by one minute of arc at the earth’s surface on a latitudinal meridian is a nautical mile.  Now any maritime chart or aviation chart/map is overprinted with the lat/long grid so it is very easy to see 1 minute of arc and therefore see what 1 nm [sic] looks like irrespective of the scale of the map.   It makes using the one in sixty easier.  One could do it in kms but I think you would need to know the scale and use a ruler to measure kms so why make life difficult?.  As the Merecats would say – Simple.   Incidentally this also explains the dominance of using knots as a measurement of speed.”

This was my reply:

“Thanks for the explanation, which I think I understand. [Actually, I didn’t fully]

In your example, the deviation from course (1 nautical mile or banana) divided by the distance travelled (60) is in fact the sine of the angle subtended, and inverting this gives 0.955 degrees – i.e. roughly one degree off course. Presumably, this is good enough for travelling short distances. ( I couldn’t see the relevance of radians, but I note that one radian is 57.296 degrees, and this divided by 60 degrees gives 0.955). So far, so good. However, as you say, this relationship is independent of measurement units.

Turning to the latitude and longitude grid, surely this only works in a due north-south direction, as the parallels of latitude are shorter as you approach the poles. Measuring from my Philips world atlas, I calculate that 5 degrees along the equator (i.e. 300 nautical miles) in Brazil represents 554 km, which gives 1846 m per nautical mile (the SI definition of a nautical mile is 1852 m), whereas, measuring horizontally from British OS maps, one degree at latitude 50 degrees north (The Lizard) represents 1190 m. At 60 degrees north (Shetland) it is 940 m. So even at the scale of the UK, there is a considerable difference – and this ignores the related problem of portraying a curved surface on a flat map! (I also thought of introducing the Heisenberg Uncertainty Principle, but that would be a digression).

I suppose that if you have a pair of dividers to hand you could use the vertical scale of minutes of latitude to set the dividers to measure in nautical miles, but assuming that the map or chart has a scale in km, it would be just as easy to set it to measure in kilometres. Or use a standard scale rule calibrated in metres at the appropriate scale (such as architects and planners have used for 40 years). (The 1939 OS national grid, which I believe is used by the army, is based on kilometre squares).

(Incidentally, I gather from browsing internet sites that GPS can use decimal degrees as an alternative to degrees, minutes, seconds – so it is not necessarily dependent on minutes – hence, nautical miles are not essential to GPS systems. As I understand it).

So my conclusion is that the claimed advantage of using nautical miles is fairly weak. It must be primarily a question of resistance to change and the historical domination of the Americans in the aviation industry. Of course, changing the habits of a lifetime is always inconvenient at first, but I would have thought the long term advantages of a world-wide system, used and understood by all for all purposes, far outweighs the temporary inconvenience of a small minority having to adjust to change.

Incidentally, as NATO armies work in km, whereas air forces work in nautical miles (and feet for height?), what units do they use when they need to talk to each other about ranges, distances, heights etc – e.g. an OS map shows that a mountain is 782 m high, so what altitude do I need to fly at to clear it? (I seem to remember a Chinook helicopter flying into a hillside on the Mull of Kintyre – attributed to pilot error – could confusion over measurement units have had anything to do with it?).

Anyway, I have gone on too long. Hope this makes some sense.”

There was no reply from my correspondent – so I did a little more research.

It seems that the fundamental problem is that maps are flat, whereas the Earth is (roughly) spherical. So a co-ordinate map grid based on kilometre squares that is suitable for a relatively small land area – say, the UK – does not work when extended to a continent. (I am advised that navigators on ships crossing the Irish Sea have to make minor adjustments when they sail from the British National Grid area into the Irish grid area, as the latter has a different origin). For longer distances, navigators use latitude and longitude as a co-ordinate system in order to determine their position and their course.

However, what I still do not understand is why this should affect the units of distance used. There is no particular logic in dividing the Earth’s circumference into 360 degrees of longitude and then into    21 600 minutes (i.e. 360 x 60), and then using the distance that one minute represents at the equator (and only at the equator) as the basis for a unit of measurement.  Wouldn’t it perhaps be more useful to divide the distance from the equator to the poles by a convenient number – say, 10 000 – and then base measurements on that?  But, oh, I forgot: that’s exactly what the founders of the original metric system did.

In fact, until the Second World War, most aviation outside America and the British Empire actually did use the kilometre for distances (and, consistently, metres for height), and indeed, for domestic aviation, Russia still does.  It was only the post-war dominance of the USA in IATA and ICAO (supported of course by the British) that imposed nautical miles on an otherwise metric world.

Or have I missed or misunderstood something?  Can anybody help?  Above all, is there any hope of getting the situation changed?

Go into your local DIY superstore, and head for the lawn mowers. Now try to compare the power of different models. For small petrol mowers it is likely to be given in cc, for large petrol mowers in hp, or PS for German models; electric mowers will be rated in W or kW.

Of course, it is rarely necessary to compare the power output of different types of mowers, because the type required is usually determined by the lawn to be mown. However, for cars the choice is not so simple, and anyone considering the purchase of an electric car will surely wish to evaluate its performance against that of comparable petrol or diesel models.

Tim Bentley, a frequent contributor to MetricViews, writes:

“With a huge growth in the number of electric cars about to be launched on the British market, it is now time to adopt the kW as the standard unit of power for all cars. Whilst kW is generally used for electric cars, hp, bhp and PS are used for petrol and diesel cars. It is important that customers are able to compare the different cars on offer and the use of a standard unit (kW) is not only sensible but essential.”

A webpage from ‘Which’ highlights this problem: www.which.co.uk/advice/power-converter/index.jsp

The arrival of electric cars also provides scope for confusion in the matter of fuel consumption. A useful article about this appears on the US site Metrication.US:

www.metrication.us/content/demise-mpg

David Brown, well known to readers of MetricViews, provides a helpful comment on the US web site.

The US article understandably omits to mention the confusion arising from the difference between the US gallon and the imperial gallon, which is still used alongside L/100 km for fuel consumption in the UK.

However, if both the British Government and the shadow transport secretary don’t want road users to get their heads round km for distance and km/h for speed, as appears to be the case, then what chance is there for MJ/km for consumption of fuel (or energy) and p/MJ for price?

Many UK road signs use improvised English language abbreviations and English language names for measurement units, in addition to extensive use of English text. This is despite the existence of internationally-recognised symbols, and standard units of measurement, which are already in use on road signs in the rest of the world.

This failure to use standard symbols and pictograms, compels Welsh traffic authorities to modify parochial English traffic sign designs, so that traffic signs in Wales can meet the requirement to be understood in both Welsh and English.

If traffic signs throughout the UK made maximum use of standard symbols and pictograms,  the majority of signs could be understood by drivers speaking any language, without additional translation.

With increased international traffic in recent years, one would expect that this aspect of traffic sign design would be given high priority in the current Traffic Signs Policy Review. However, some new road signs planned for introduction in 2010, will actually exacerbate the problem. For instance, the new cycle route directional sign, that gives distances using estimated journey times, does not use the standard symbols for hour (h) and minute (min), but uses improvised English language abbreviations instead. Consequently, a special bilingual version will be required when it is used in Wales.

Metric solution

The diagram below shows how simple the above cycle route sign would be if standard symbols and units of measurement were used.

All metric units of measurement have standard internationally-recognised symbols. This means, for example, that the ‘km’ symbol will be understood to mean ‘kilometre’ regardless of language.

Existing language-dependent signs can also be simplified by using standard symbols.

The use of yards is not compatible with the Welsh language.

The UK is the only country in the world that uses yards on road signs (the USA uses feet or metres).

Further examples of how current parochial traffic signs could be more widely-understood by using standard metric symbols can be seen on the UKMA website.

1968 Vienna Convention on Road Signs and Signals

The issue of designing signs for road users of different languages is not a new one, and was addressed many years ago by those countries, including the UK, that signed up to the 1968 Vienna Convention on Road Signs and Signals. This international treaty lays out the principles, and standard symbols, for road signs used throughout most of the world, and includes the following statement:

“The Contracting Parties,
Recognizing that international uniformity of road signs, signals and symbols and of road markings is necessary in order to facilitate international road traffic and to increase road safety,
Have agreed upon the following provisions:
…”

The huge increase in international traffic over the past 40 years, and the modern needs of the Welsh language, should make the Vienna Convention even more relevant today, but it seems that the Traffic Signs Policy Review is not addressing this fundamental issue. So, if it is not going to be addressed in, what was described in September 2008 as, “the biggest review of British road signs for 40 years”, when will it be addressed?

Traffic Signs Policy Review

Details of the Traffic Signs Policy Review can be found at the following link
http://www.dft.gov.uk/pgr/roads/tss/policyreview/

You can apply to join the sounding board, or comment directly using the following e-mail address
traffic.signs@dft.gsi.gov.uk

You can comment on the new journey-time cycle route sign, and other proposed amendments to traffic signs regulations, in the DfT consultation. Details of which can be found at the following link.
http://www.dft.gov.uk/consultations/open/trafficsignsamendmentregs/

Other traffic sign issues that can be solved by using univerally understood symbols and units of measurement are described in UKMA’s leaflet Traffic Signs 2.0 . Free printed copies can be obtained by e-mailing secretary@metric.org.uk .

The long-overdue official acknowledgement that road safety can be improved by using metric measurements on vehicle restriction signs, comes as one of the proposed changes to the Traffic Signs Regulations and General Directions (TSRGD) 2002. The DfT has calculated that savings can be made from the projected reduction in costly accidents, such as bridge strikes, that currently involve a disproportionate number of foreign drivers, who generally do not understand restriction signs in feet and inches. The change will of course benefit British drivers too, as there will no longer be a need to know vehicle dimensions in two incompatible measurement systems.

In the Traffic Signs (Amendment) Regulations and General Directions 2010 consultation documents, it states:

“We are making changes to require both metric and imperial triangular warning signs to be displayed to give warnings of restricted headroom, with the upgrade being complete in four years’ time. Using the imperial sign on its own will no longer be permitted.

We are making similar changes to require both metric and imperial measurements to be displayed on all width and height restriction roundel signs, with the upgrade being complete in four years’ time. The current imperial-only signs shown in diagrams 629 and 629.2 will be withdrawn.”

“… approximately 10 – 12% of bridge strikes involved foreign lorries. This is disproportionately high in terms of the number of foreign lorries on the road network.

… Furthermore, for several years this Department has recommended, through the Traffic Signs Manual, the use of the dual unit height limit warning and regulatory signing in preference to the imperial only alternative.”

This is a welcome development. However, by replacing imperial signs with dual unit signs, an opportunity is being missed to make further savings, as in the not-too-distant future, the new dual unit signs themselves will be replaced with Vienna Convention-compliant metric-only signs. Garage forecourts, warehouses, and many car parks have already been using metric-only height restrictions for many years.

The proposed amendments to the TSRGD have come about as part of the Traffic Signs Policy Review, which was announced in September 2008. UKMA’s contribution to the review included the production of a leaflet, Traffic Signs 2.0, which highlights the many issues within the remit of the review that can be solved by switching to metric road signs. Unfortunately, the DfT continues to refuse to consider switching to metric measurements on road signs, and as a consequence it has dismissed the proposals in the leaflet, apparently even the recommendations that are not directly related to metrication, such as the use of language-independent up-arrows to indicate hazard extent, and the replacement, where possible, of text-only signs with standard pictograms.

As an example, the DfT has overlooked the principles of the 1968 Vienna Convention on Road Signs and Signals in the proposed new warning sign (diagram 7014.1) that indicates a temporary or permanent reduction to bridge headroom. The sign is text only, and consequently a non-English speaker might be unaware that the figures in brackets relate to a height restriction.

The diagram below illustrates how the essential information in the sign can be shown in a language-independent way using standard symbols from the Vienna Convention.

The Vienna Convention does not prescribe feet and inches on restriction signs though, and stipulates that the measurement units should be in metres only.

Traffic Signs Policy Review

Details of the Traffic Signs Policy Review can be found at the following link.
http://www.dft.gov.uk/pgr/roads/tss/policyreview/

You can apply to join the Traffic Signs Policy Review sounding board, or comment directly using the following e-mail address traffic.signs@dft.gsi.gov.uk

You can comment on the new signs and other proposed amendments to traffic signs regulations in the DfT consultation, details of which can be found at the following link.
http://www.dft.gov.uk/consultations/open/trafficsignsamendmentregs/

UKMA’s Traffic Signs 2.0 leaflet can be downloaded by clicking on this link.  Alternatively, free printed copies can be obtained by e-mailing secretary@metric.org.uk