Transport for London raises the bar on vehicle signs

Metric Views is pleased to give credit where it’s due, and this week it is due to Transport for London (TfL) for raising the bar on the signage of vehicle restrictions. We have previously criticised the signing at the Rotherhithe Tunnel, a road operated by TfL, but a few weeks ago new signs were installed which meet the standards recommended in the Traffic Signs Manual.

Previously, vehicle restrictions were signed on a hodge-podge of different signs, some clearly showing their age. Height and width limits were both signed in both feet and metres, but inconsistently, with some signs showing only feet/inches and others both units. Length signs showed only feet, and in a style not permitted under the current regulations.

A few weeks ago the signing was overhauled, with the previous collection of signs being swept away and replaced with smart new signs incorporating the best practice, as outlined in the Traffic Signs Manual.

These include:

– consistent application of dual units for height and width limits;
– length limits in the correct format, including the 10 m limit;
– use of the correct lower case “t” for tonne

The new signs should increase driver comprehension of the vehicle restrictions in force and provide a good template for the operators of other roads with vehicle restrictions.

Ultimately the UK Metric Association looks forward to the time when imperial units will no longer be necessary, allowing even clearer signs.

The only downside is that the new emergency escape signs within the tunnel, erected at a not inconsiderable expense, use yards instead of metres. Metres are required under the Vienna Convention, and indeed reading the UK government’s position suggests that metres should be used in this case, as it pertains to personal safety; while drivers unfamiliar with yards could arguably be expected to learn them before taking to the road, this isn’t true of people who happen to be being transported through the tunnel when they find themselves in an emergency situation.

Alas the Department for Transport has chosen not to enact the sign to the standards required in the Vienna Convention, nor to follow UK government policy on metrication, but to require the erection of new signs using antiquated units. More on this latter point can be found in this earlier post, part of which is reproduced below for ease of reference:

Signs indicating the emergency escape routes in tunnels are of critical importance to the safety of tunnel users, given the particular hazards of fire and smoke within tunnel environments. Sadly, the government’s irrational position on units of measure even extends to these safety critical signs.

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:


21 thoughts on “Transport for London raises the bar on vehicle signs”

  1. Is there any way of finding out who the owner is of the single-digit IQ brain that is responsible for this obstinate stupidity with pedestrian escape signage? Then write letters to him/her, copies to your MP, the Minister, the PM and Deputy PM.


  2. I believe that the new signs in the Rotherhithe Tunnel are a great precedent for the Department for Transport to put similar signs at low bridges with a record of bridge strikes. If dual signs are important in the Rotherhithe Tunnel, then they are even more important at low bridges that are often struck.

    There need be no question about which low bridges should be dealt with first. A good list can be found at Just begin with the bridges that are struck the most! Of course, there could be good reasons why the order should be varied, but I think that this list would be a good place to start.


  3. The problem with the metre is that it shares the same abbrevaton as the mile and I think that is one of the reasons for its slow progress in its use for linear distances on road signage.
    I expect the legal types in the DfT are scared someone will sue them because they thought that 54m meant 54 miles and decided not to run to safety! This presents a dilemma as it’s rather late in the life of the mile to give it a new abbrevation of mi. In the short term, until the mile ceases to be used it would make sense to use the complete word, metres. Some people try and get over the problem by using the dreaded Mtrs which I hate to see.


  4. To me it seems the Department for Transport (DfT) is being spiteful and Transport for London (TfL) is obstinate. Both are not thinking of safety.

    It is blatant show of power that the signage at the Rotherhithe Tunnel is dual unit and seems to be proper convention. Best of both worlds to maintain peace. Meanwhile the other signs that seem to be in convention colour code is left in yards and could have been in meters and or dual as in the first example.

    I also noticed both departments seemed to ignore their own convention of not having the words yard and feet in Irish clos and chos or Welsh llath/iard and troed!


  5. @Tim – to this day I always look back at a DfT memo dated 12th Jan 1989 (from a FoI request, possibly even by the UKMA) which discusses the very problem of the use of “m” for miles. The paragraph in question states:

    “At present ‘m’ is used for miles on certain directional signs and for metres on regulatory or warning signs. The next round of consultation on new traffic sign regulations (a Statutory Instrument) proposes to remove this anomaly by removing the miles reference”

    So, nearly 23 years later we’re still waiting for this to happen.

    Rather more telling is a scribbled note in the margin next to the first sentence which says “What signs? and who allowed this to happen?” Is somebody asking why “m” was being used for miles or how “m” had managed to make it’s way onto regulatory and warning signs? However more telling was the comment further up the page that stated “metrication of the yard could be accomplished at relatively little costs providing this were done under the normal cycle of sign renewals”

    You don’t have to look very far to see why we’re still even discussing this!


  6. @ Tim Bentley:
    With respect mi. is the abbrevation for mile. Also stat mi. for Statute miles and naut mi. for Nautical miles.
    Be well,


  7. The Rotherhith tunnel sign could be criticised for containing more information than a passing driver can reasonably expect to assimilate momentarily.

    It is clearly a strong case for metric only which would allow each component to be larger and simpler.


  8. The professional drivers who need to see the information on the Rotherhithe Tunnel sign are most likely to be in an age group which received a metric education at school and should understand the metric units. Even if that is not the case, i.e. if the driver is well into his sixties and only learnt ‘imperial’ at school, it is reasonable to expect the driver to have updated his skills during his working life as part of his continous training and to know the dimensions of his vehicle in metric units. The inclusion of feet and inches serves no useful purpose and the repetition of the vehicle length sign to show those units also slows down the intake of the information.


  9. My first reaction from a driving point of view is that of trying to read ‘1568 and 54’ while driving irrespective of the units, it would not get that far. Better to have used 1570 and 50 and moved them 3m to the right if they wanted the accuracy well within 10 percent.
    Not criticising Jake, but I often wonder who these ‘old folk’ are that don’t understand the metric system. I am well into my 60’s and retired years ago. My later education was 100 percent metric and I have just been looking at one of my text books, fully revised into the then m.k.s. system in 1958. Glancing over the calculus, vectors and trig articles therein I also wonder why today I have a rated mathematical ability (a UKMA metric / imperial test I think) of less than a primary school pupil!
    You do not need an education to understand metric – that is the whole point of it.
    It is those stupid imperial things that are so difficult.


  10. Indeed, Transport for London deserve credit for making the Rotherhithe Tunnel advance signage dual unit. The issue of using ‘yards’ on pedestrian emergency exit signage is indeed troubling; the problem is that they are classed as road signs like any other and are therefore specified under TSRGD, which, as we know, never uses metres for distances (although it is only a matter of political will that procludes the regulations being changed to replace yards with metres).

    @Michael: the Network Rail 2010/2011 bridge strike data is very interesting. I’ve done a summary check via Google Street View of all the bridges that suffered >10 strikes via Google Street View to see what signage is in place (at the time the imagery was captured, at least):

    *A52 Barrowby Road, Grantham, Lincolnshire (18 strikes): dual unit
    *A624 Hayfield Road, Chinley, Derbyshire (18 strikes): IMPERIAL ONLY
    *A2218 Southend Lane, Lower Sydenham, Greater London (17 strikes): dual unit (IMPERIAL ONLY on western approaches)
    *Kenworthy Road, Homerton, Greater London (12 strikes): dual unit (IMPERIAL ONLY at “overheight vehicles” divert point on northern approach)
    *Station Road, Langley (12 strikes): dual unit (IMPERIAL ONLY verbal warnings on approaches)
    *Abbey Road, Thetford, Norlfolk (11 strikes): IMPERIAL ONLY
    *A507 Baldock Road, Baldock (11 strikes): IMPERIAL ONLY
    *Cook Street, Glasgow (10 strikes): dual unit
    *Lower Downs Road, Wimbledon, Greater London (10 strikes): twin signs (IMPERIAL ONLY on approaches)
    *Newhouse Road – Long Drive, South Ruislip, Greater London (10 strikes): dual unit (IMPERIAL ONLY at “overheight vehicles” divert point on northern approach)
    *Summer Lane, Barnsley (10 strikes): IMPERIAL ONLY

    As we can see, four of the most frequently struck bridges in the country (including the joint first most struck bridge) still have imperial-only signage, and five others are lacking dual unit signage at many or all crucial approach points.

    One wonders if Network Rail are really serious about eliminating strikes due to foreign driver miscomprehension if they still haven’t managed to erect dual unit signage at and on the approaches to the most struck bridges in the country.


  11. With regard to the frequently hit bridge in Glasgow, there are specific issues involved.

    The two most frequently hit bridges used to be Cook Street & West Street, which are just round the corner from each other. West Street used to be hit more often, and was the site of a major crash involving multiple fatalities when hit by a double decker bus carrying a Girl Guide troop.

    In both West Street & Cook Street, a vehicle will have to pass under 2 railway bridges which are very close together. Both bridges are marked with the height of the lower bridge, which is roughly one metre lower than the higher bridge. In many of the strikes, the vehicle has safely got under the first (higher) bridge and then hits the second (lower) bridge.

    As such, it has been suggested that the signs on the higher bridge may have been ignored by drivers as they appear to be incorrect, and the drivers then go on to hit the lower bridge.

    As a result, West Street has been closed to through traffic, and is now used as a car-park for the adjacent subway station.

    The second factor that may influence the number of strikes at Cook Street is that FirstBus have a major depot close by. Apparently their double decker busses based at this depot have big signs in the driver’s cab saying “Do not use Cook Street”

    These signs are not metric or imperial, and are specific to this one depot. Unfortunately, they still seem to fail to prevent the occasional driver error.

    I would therefore suggest that the strikes at this particular bridge may not be due to confusion between imperial and metric. In this one instance, it is probably more due to bus drivers forgetting that they are in double decker busses as they set off from the depot.


  12. The persistence of dual units in UK society has the potential to cause accidents. That is plain common-sense.

    Understanding height in metres is a “no brainer” – what is there to understand if you take the trouble to acquaint yourself with the height of your vehicle in metres – its only a number and everyone can tell if one number is bigger than another.

    We don’t really need actual incidents to justify the move to a single system. That’s the philosophy of waiting for an accident to happen before taking precautions against a foreseeable hazard.


  13. @Hughster: good research, very interesting. However, it is not Network Rail’s responsibility but the highway authority’s. Perhaps UKMA should write to these authorities and point out that their signage doesn’t appear to comply with the recommendations in the Traffic Signs Manual and that to protect themselves from blame they should add metric signs ASAP.


  14. I believe that the push for dual signage is an obvious safety issue. The Department for Transport will be culpable if the recommendations are not taken up.


  15. My push is for single signage, for me dual signage is a no brainer and a waste of time, money and effort.
    100 days to go to the start of the London Olympics. Far too late for our optimistic wish for road metrication to be a done deal by this time. Lets see what happens when ‘millions’ of visitors arrive in Britain having been told it is now a metric country, only to find a set of road and shop signs that they know nothing about and for which they have no prior warning.
    OK, right, they want to come to our country so they better learn our stupid measuring system, time to think again I think.


  16. Metric-only signs are used all around the country by the private sector with no damaging effects. Despite the successful, well-established exclusive use of metres in so many places, the DfT still refuses to allow it on any public signs for ideological reasons.

    Unfortunately, the DfT is still stuck in an anti-metric mindset and is out of touch with the rest of society and the modern world. Given that a metre is only slightly longer than a yard, why is the DfT so strongly against the use of metres?


  17. Ronnie Cohen has it exactly right … the opposition to metrication in the government is for purely ideological reasons. And, I would add, also for political reasons.

    So, a major factor for the future development of the UK is being cynically used as a tool to curry favour with the voting public simply in order to try and stay in power. How utterly reprehensible! And how utterly not surprising. 😦


  18. To add to Ronnie’s and Ezra’s comments, I can’t think of anyone seriously benefitting from the status quo regarding the metrication situation in the UK, other than some getting an ego boost perhaps, but that’s about it. Everyone is losing out in some way.

    The DfT, with their current attitudes, are only delaying the inevitable and increasing the costs for a future DfT that will surely do the full metric road signs changeover (and not just metric-only restriction signs). Who knows when that will be, but it has to happen eventually.


  19. Regardless of the unit used for the pedestrian exit sign, surely in a state of emergangy the only information you would care about is which exit is closest, not “which exit is closest and how long will it take me? How many steps will I need?”. At the end of the day meters and yards are so close in length that over short distances we are really splitting hairs.


  20. @Robin
    True, metres and yards are within 10%, the problem is many (or most) foreigners, Americans included will not know this fact, nor indeed will many from UK I suspect. Everyone will know what a metre is.
    As for not knowing how far to the exit not being important, I can stake my life on the fact that it is of VITAL importance. If one is in smoke, do you run and risk injury, or is there time to walk? Is the nearest exit before or after the incident, or do you take the longer route and go the other way? If it is dark (assuming the sign is lit) knowing how many paces to take is a pretty useful aid in finding an exit not knowing if it is a major opening or more likely just a tiny hole in the wall (or floor or ceiling if it is an escape hatch).


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: