Driver location signs – possibly coming to a motorway near you

Martin Vlietstra, a regular contributor to Metric Views, draws our attention to a trial of driver location signs, to be conducted by the Highways Agency. Martin notes that these signs are metric, and draws attention to the explanation for this. 

The Highways Agency (HA) has received funding to conduct trials that involve the erection of 3000 driver location signs (DLS) on Britain’s motorways and trunk roads – see http://www.highways.gov.uk/business/14730.aspx.  DLS are blue signs with the following items of information in orange:

*Road Name (e.g. ‘M25’)

*Carriageway (Usually ‘A’ or ‘B’)

*Location

The location is the nominal distance of the sign in kilometres from the reference point of the road concerned.  In the case of the M25, the reference point is the north bank of the Essex/Kent section of the Thames. 

The purpose of the trials is to see whether or not such signs can assist the emergency services in responding more quickly to incidents upon receipt of a call from a mobile phone. A further document http://www.highways.gov.uk/business/16043.aspx  discusses DLS from the point of view of responses to incidents.

An update of the specification of Driver Location Signs can be found on the HA website:  http://www.highways.gov.uk/business/16039.aspx.  This update also includes a link to FAQ, question 14 of which deals with the reason why the signs are in kilometres.

DLS are a welcome addition to our roads, but for them to be really effective, drivers need to understand why they are there.  This can be done in a number of simple ways:

* Proper publicity by the HA

* Numbering of Service Areas by reference to the nearest DLS

* Numbering of trunk road exits (and possible motorway exits at a later date) by reference to the nearest DLS. This is the practice in Spain, South Africa and the US.

In Italy, DLS are frequently used to advertise locations of out-of-town establishments, for example, a restaurant that I used when I was working in Italy was advertised as being “on the Via Salaria at km 19.7”.

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14 Responses to Driver location signs – possibly coming to a motorway near you

  1. Alex Bailey says:

    While the DLS is a great idea, more credit should be given to the "marker posts" that already exist along all of our motorways and are becoming more common on trunk roads. These marker posts show the same distance information in increments of 100 metres and as anybody who has broken down on a motorway will know, also point to the nearest emergency telephone.

    These marker posts have been there since the very early days of the motorway and although many have (and still are) sucked in by the myth that these posts are 100 yards apart, this is untrue. The very first marker posts installed were "half a furlong" apart which is 110 yards - perhaps coincidence, perhaps design, but that is 100.58 metres!

    As well as the obvious safety function, these marker posts also work well as a tool to judge distance between vehicles at speed and if you know the distance to your destination in km are fantastic for travelling with kids (from simple countdown to your destination for younger kids to maths for the older ones - working out distances or speeds). They would, of course, be an additional aid in route planning if our other signs and road atlases were also metric!

    It's also ironic that, if you see temporary signs on motorways such as "x yards" before roadworks that the signs are generally placed right next to these marker posts meaning yards=metres. Perhaps this is where the myth above comes from... more importantly though it blows out the theory that British drivers wouldn't be able to cope with metres!

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  2. Ezra Steinberg says:

    Alex makes a shockingly pertinent point. If distances to road work are posted in yards with the expectation that British motorists will understand them safely, then there is no reason not to post them in meters and simply tell the public that for all practical purposes they can be thought of as "yards"!

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  3. Daniel Jackson says:

    I wonder how feasible it would be for distance signs to show metres at exact metre distances but without any unit labels. For example a sign could read: "Curve ahead 200". The 200 would imply metres, but imperialists could think it is yards.

    This way those who try to damage metric signs by changing the units wouldn't be able to and should the day come when all signs are metricated, then the cost is reduced because nothing will have to be done to these signs.

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  4. David says:

    I think it would be a great idea to use distance location signs as the basis for junction numbers: it would save a lot of expense (renumbering the existing junctions or having strange junction numbers) and confusion every time a new intermediate junction is built. It would also mean that you could easily work out how far it is to the junction you need to exit at, from your current position: eg, junction 150, 150 km if following the road from the start or 100 km if you join the road at junction 50.

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  5. Dave Brown says:

    I find it odd that the M25 markers have been set at x.3 and x.8 km from the origin. Why on earth didn't they use x.0 and x.5? However I was pleased to see on the M11 this morning just south of junction 8 (Stansted Airport) they are erecting new distance markers: M11 B 42.5; M11 B 42.0 etc. That makes a lot more sense to me.

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  6. John Frewen-Lord says:

    Road exit numbers on North American major highways are almost universally given in miles (USA) or km (Canada) from the distance reference point (usually the start of the highway - in the case of Highway 401 in Ontario it is in Windsor on the US border, and stretches to the Quebec border, some 800 km (very approximately) away. Thus exit 427 is 427 km from the reference point. This has some useful features, two being that new intermediate junctions can be easily added (as David says), also that it is easy to work out how far you have to go to your chosen exit. Another example of not only other countries doing things better than the UK, but the UK stubbornly refusing to learn from them! Ostriches anyone?

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  7. acer says:

    Road exit numbers on North American major highways are almost universally given in miles (USA) or km (Canada) from the distance reference point (usually the start of the highway - in the case of Highway 401 in Ontario it is in Windsor on the US border, and stretches to the Quebec border, some 800 km (very approximately) away. Thus exit 427 is 427 km from the reference point. This has some useful features, two being that new intermediate junctions can be easily added (as David says), also that it is easy to work out how far you have to go to your chosen exit. Another example of not only other countries doing things better than the UK, but the UK stubbornly refusing to learn from them! Ostriches anyone?

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  8. Jacqui says:

    These markers are a superb idea, but only if the emergency services know that they're there and how to use them...We made a call whilst on a motorway to let the police know there was an injured swan in the middle of the motorway and it was going to cause an accident...We were asked our location and didn't have a clue, so we gave them the numbers on the location markers...Imagine our dismay when the person on the other end of the phone said she didn't have a clue what I was talking about and just kept repeating 'but, where are you?'...How do you know if you're not near a junction???????
    I just hang the phone up and thought I hope I never have an accident on the motorway and need the emergency services...It really didn't instill any confidence in me whatsoever....You might just as well say 'I'm between this tree and that tree' !!!!!!!!!!!

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  9. John Steele says:

    @ Jacqui

    That must have been an unsettling experience. Four years after the start of the trial, the signs fail at the very purpose for which they were created, to help emergency services respond to an incident.

    As pointed out above, US exit numbers on freeways are the mile marker values rounded to the nearest whole mile. As a result, anyone reasonably familiar with the road (or looking at a map) can at least narrow the mile marker reference to between two exits (based on the next larger and next smaller numbered exit). The emergency vehicle can then use the mile marker sticks to narrow the range until they see the incident. Obviously, the scheme works as well in kilometers (as Canada proves).

    Using the rounded values as exit numbers is key to people getting familiar with the system. Otherwise the markers are ignored.

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  10. Patricia Golds says:

    I have read all the above remarks and agree that Driver Location Signs (large blue rectangular) and Distance Marker Posts (red, white and blue 'sticks') fulfil a need. However, nobody has mentioned that these signs are, actually, illegal, because distances in Britain are still supposed, by law, to be in miles, yards, furlongs, etc. I believe this is intended to introduce metric distances, without the rule of law. Metric distances are permitted, but alongside Imperial measurements. Even if one approves of metrication, it is still not right to do it 'by the back door'.

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  11. John Frewen-Lord says:

    @Patricia:

    These signs don't actually show distances, just a specific location. There is therefore no reason why they should be considered illegal. As for metricating 'by the back door', as you describe it, all our roads are already designed and built using metric measurements and design standards/codes, so there is nothing furtive about labelling these markers in metric units.

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  12. michduncg says:

    @ Patricia

    The index markers you refer to are not illegal as they do not refer to a unit of measurement. They are merely presented as index locators so that people can easily identify their location on any major road. It is one of the the rare pieces of DoT forward planning that the markers are placed 100m apart so that when distances are metricated these signs will already be in the right place.

    As for metrication being by the 'back door' - I don't think that clear Government intention announced as long as go as 1965 and backed up by other policy decisions in the meantime including a change to Weights and Measures in 1994 is 'back door'!

    Finally, the important thing about measurements is that people understand them. Following the very clear use of metric in all events at the 2012 Olympics the universal acceptance of metric measurements is clear. I appreciate that population at large is familiar with the term 'mile', but ask them for a definition of it and you will not get a reliable answer. I asked 15 people under the age of 40 how long a mile was and without fail, not one of them knew. Same goes for the yard and as for the furlong, I have no idea and really don't care! Ask young people how many inches in a foot or ounces in a pound and again they have no idea. So how is that good for us as a country? But ask them how many metres in a kilometre or grammes in a kilogram and they do know.

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  13. BrianAC says:

    @Patricia Golds: -
    The above links no longer work, here is one new link http://www.direct.gov.uk/prod_consum_dg/groups/dg_digitalassets/@dg/@en/documents/digitalasset/dg_185820.pdf - for the locator signs.
    These are specified by the DfT, so if they are illegal it is further evidence of the stupidity of their own laws that they themselves have to break them in order to provide sensible and meaningful information. In my view the are not illegal because they do not have 'km' on them, it is just a number that us plebs are not supposed to understand but the emergency services find essential. A further indication of the stupid mindset of those in power over these matters.

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  14. derekp says:

    The units of measurement directive permits, but does not require, only "road traffic signs, distance and speed" to be in imperial units. Our own DfT decides what is legal within this framework when issuing traffic signs regulations. Some comments on this article have suggested that a location marker does not a indicate a distance, but in any case the use of imperial measures on traffic signs is an option not a requirement. Surprisingly, the DfT interprets 'distance' to include height, width and length.

    The permitted imperial units on road traffic signs are mile, yard, foot and inch, so we should forget furlongs, chains, rods and other historical baggage that was dropped by successive UK Weights and Measures Acts during the last century.

    Ms Golds suggests that location markers are part of a move to a single, simple and coherent measurement system for the UK "by the back door". If only!

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