ARM will be interested to know that part of the reason for not allowing the m symbol on road signs to mean metre is because of the potential confusion with the m for mile.

The Department for Transport regard the yd symbol as an alternative for the metre because they are effectively the same within the limits of accuracy distance indications. It has nothing to do with people not understanding metric.

If you don't believe me (as I'm sure you won't) write and ask them.

If you were a GPS nut like me you'd realise quite how "off" speedos and mileometers are.

BTW- martin will tell you about those km sticks by the side of the road whereas the 3-2-1 yard marker boards are slightly closer together than those 100mtr interval sticks.

I wonder why?

re (Stan): "The Department for Transport regard the yd symbol as an alternative for the metre because they are effectively the same within the limits of accuracy distance indications. It has nothing to do with people not understanding metric".

REPLY: It's very encouraging when your opponents post what is, to put it delicately, utter nonsense. Does the same apply to bridge heights? LOL

<<REPLY: It's very encouraging when your opponents post what is, to put it delicately, utter nonsense. Does the same apply to bridge heights? LOL>>

Oh really. Then consider:

(i) Bridge heights are not given in yards or any unit that has a close approximation to metric, hence metric is allowed on them.

(ii) There is no danger of confusion with m for mile.

(iii) The degree of accuracy is more critical than for distance indications.

Hence an entirely different case.

Stan If you had a GPS you'd know that it's closer to yards than metres.

Also I drove a van once with km odometer. And that showed that they weren't metres.

However, for rough approximation where accuracy can only be dubious (eg, claiming that a pub is "100 yds on the left" to a member of the public) then I'd agree that metre and yard are practically the same thing. Give or take a few inches of light in a vacuum ;-)

Some 3-2-1 countdown markers are at 100m intervals and others are at 100yd intervals.

If you are a passenger in a car, you can identify which is which by comparing their location with the closest 100m location markers. If the difference between the countdown markers and the location markers is the same, they are at 100m intervals, if they get closer, they are at 100yd intervals.

<<<Some 3-2-1 countdown markers are at 100m intervals and others are at 100yd intervals.>>>

I must admit that I take the word "yards" on British road signs to mean metres anyway so I would never have noticed this - but some of the posters on here will be deeply upset if this is really true..

indeed certain posters might even start suggesting that having them at 100/200/300m is highly dangerous and start moving the markers

I sort of metioned that (on your behalf).

Except that there are no 3-2-1 100metre marker boards.

On motorways they are 100yds apart.

On other roads they could be anything, depending on circumstance.

Since you have - I will repeat myself (again)

Near Bridgend in a place called cefn cribbwr there is a level crossing (railroad X-ing) placed on a corner around a bend with no barriers (just the lights). The speed limit is 30mph and the 3-2-1 marker boards are about 100ft apart.

The reason for this is that if they were 100yds apart it would not "flow" properly with the danger present. In fact - it would look silly.

Do you see, Martin?

<<<Except that there are no 3-2-1 100metre marker boards.>>>

How do you *know* ? Would there be crashed cars strewn all over the motorway exits if they were?!

<<If you were a GPS nut like me>>

Why? Are you afraid of getting lost? What do you do with the information? Do you keep a log?

I always wondered who "Captain Slogg" was ;-)

Andy - the information was gleened from a publication.

It said something like "motorway countdown boards are placed 100 yds apart however those not on the motorway may not be 100yds apart".

I believe that Martin thought the "may not be" referred to "they are really 100m apart".

My example showed how varied they can be apart with my example of marker boards around 100ft apart.

<<Stan If you had a GPS you'd know that it's closer to yards than metres.

Also I drove a van once with km odometer. And that showed that they weren't metres.>>

I'm not claiming that all signs with yds on them have been placed according to distances measured in whole numbers of metres. I'm only passing on the fact that the DfT now regard distance signs with yds on them as sufficient for the purpose of indicating the distance in whole numbers of metres within the normal limits of accuracy.

In the event of a publicised programme of change to metric they will allow such signs to persist (in some cases) until they are due for replacement in order to reduce the costs. It's purely a strategic point. They are not maintaining them because they are worried that people will not understand metres.

For all we know there may be signs out there that have deliberately been placed so that they meet the requirements for distances in both metres and lots of 0.9144 m within the normal 10 m margin.

<<distance signs with yds on them as sufficient for the purpose of indicating the distance in whole numbers of metres within the normal limits of accuracy>>

I agree upto a point - however the common 800yd sign (for impending traffic change, eg traffic lights) is almost a whopping 100yds out if you were to apply that logic.

Pace out 300ft to see how off this would be.

<<
Near Bridgend in a place called cefn cribbwr there is a level crossing (railroad X-ing) placed on a corner around a bend with no barriers (just the lights). The speed limit is 30mph and the 3-2-1 marker boards are about 100ft apart.

The reason for this is that if they were 100yds apart it would not "flow" properly with the danger present. In fact - it would look silly.

Do you see, Martin?
>>

I was talking about motorway countdown markers. I don't think that there are any level crossings on motorways.

A hundred yards is nothing in the confused world of UK measurements...

How many British road users could tell you how far half a mile is to the nearest 100 yards?

If you are in favour of a mixture of measurements, one thing you have to accept is that peoples won't have as accurate a perception of them, as they would if there was consistency.

I think you might be speaking for yourself Andy.

..if so that is very worrying, because I have a better sense of measurements than the average

Seriously, think about my question above. What percentage of road users would be able to tell you to within 100 yards? 10%? pro0bably not even that.

People associate yds with walking distances - equating to a pace per yard.

Someone saying "about 100yds on the left" would mean that they'd guess it out at 100 paces. The viewable distance becomes associated with this.

Mileage is usually assoc with driving.

If you ask someone how far -say- their home is away from work they can usually predict how far it is in miles (sometimes to the half mile if the distance is short) quite accurately.

As far as quarter miles - I'm pretty confident that most will get it right - my Dad used a qtr m the other day.

BTW - something to annoy you Andy - one of the kids at the set of Charly and the chocolate factory was excitidely talking about the 50ft chocolate fountain yesterday on TV.

<<<one of the kids at the set of Charly and the chocolate factory was excitidely talking about the 50ft chocolate fountain yesterday on TV.>>>

and how high was it?

The kid was far too young to have been dabling in drugs, Andy!

<<I agree upto a point - however the common 800yd sign (for impending traffic change, eg traffic lights) is almost a whopping 100yds out if you were to apply that logic.>>

The 800 yd sign isn't very common, at least not for permanent signs. The rules actually say that distances over 1/3 mile (587 yd, 536 m) must be signed in miles not yards.

<<
If you are a passenger in a car, you can identify which is which by comparing their location with the closest 100m location markers. If the difference between the countdown markers and the location markers is the same, they are at 100m intervals, if they get closer, they are at 100yd intervals.
>>
Martin, each pair of subsequent markers would only be about 10 metres closer than the previous. I don't know how you can detect such a difference with your eyes (unless the first pair coincided).


<<
How many British road users could tell you how far half a mile is to the nearest 100 yards?
>>
Why does that matter? That's trivia, it's not useful to most people besides traffic engineers.


<<
If you are in favour of a mixture of measurements, one thing you have to accept is that peoples won't have as accurate a perception of them, as they would if there was consistency.
>>
But their perception would be good enough for whatever they need to do, and that is all that is necessary.

<<<How many British road users could tell you how far half a mile is to the nearest 100 yards?
>>
Why does that matter? That's trivia, it's not useful to most people besides traffic engineers. >>>

It matters because it is crucial to knowing how far half mile or quarter of a mile is.

<<The 800 yd sign isn't very common>>

Not True!

Next time you are out and about check out the "traffic lights coming up" signs on major roads - and also "men at work" approach signs on major roads. Also on motorways its used for when a lane is about to be absorbed or ended. They have to be posted as:

800 yds
600 yds
400 yds
200 yds

Have you never noticed it as a handy countdown feature as you're going along?

<<It matters because it is crucial to knowing how far half mile or quarter of a mile is.>>

It seems to work then!

<<
<How many British road users could tell you how far half a mile is to the nearest 100 yards?
>>
Why does that matter? That's trivia, it's not useful to most people besides traffic engineers. >>>

It matters because it is crucial to knowing how far half mile or quarter of a mile is.
>>


The way you know how long any distance is is by experience. You can "feel" a half mile. If you know how long a mile is, you know how long a half or quarter mile is. Yards are a separate story, used for smaller distances. There is no need to connect the two.

<<
Yards are a separate story, used for smaller distances. There is no need to connect the two.
>>

Pedestrians have a need to conenct the two. For example, it is about 1100m from my office to the nearest tube station. I checked the distance on a map in my personal organiser when I was deciding whether to use a second tube line for two stops or whether to walk. It is also about 2km from my home to my main-line railway station. On the other hand the closest mail box is abuot 300m from my home.

I think that the overlap between metres and kilometres can easily be seen here. If I wer usign yards and miles where dose one stop using yards and start using miles - the converion is a lot more difficult.

You live an exciting life, martin.