What doe these m-way signs mean?

[jaffamuffin]

Been wondering for a while when travelling up and down the M6 what the significance of these type of signs are - I thought it may be related to bridges/tunnels along the motorway but not sure - anyone know what the numbers mean?

[Beardy5632]

They're the distances in kilometres of the road. The letters mean:-
A-Away from London.
B-Towards London.
J/K/L/M-Sliproads.

[Haydn1971]

More details can be found in our wiki pages

Here > Driver Location Signs

[jaffamuffin]

Cheers. I wonder how many people actually know what these mean and what they are called, thereby bringing into question how useful they actually are?

Is it mostly emergency services that use them between themselves?

[nowster]

They're the distances in kilometres of the road. The letters mean:-
A-Away from London.
B-Towards London.

London distances only applies to radials of London. It definitely doesn't apply to: M56, M62, M66, M67, M74, A1(M), etc.

I've updated the Wiki page to expand on this.

[wrinkly]

And I've added a qualifying clause to what he said about the A74(M).

Also a bit on marker posts.

Is there anything on emergency phone numbering?

[michael769]

Cheers. I wonder how many people actually know what these mean and what they are called, thereby bringing into question how useful they actually are?

Is it mostly emergency services that use them between themselves?

I think the idea is that drivers don't need to know what they are:

Driver: "help! My car is on fire/broken down/crashed"
Control Room: "Where are you?"
D: "Ermmmm????"
CR: "Can you see a little sign with numbers and letters on it?"
D: "Yes"
CR: "tell me what it says"
D: "Blah blah blah"
CR: "OK help is on it's way"

[Steven]

There is a story, probably an urban myth that talks about a broken down driver on the M6 getting confused as to whether they were near Warrington or Walsall...

These signs should prevent that sort of silliness when people use their mobile phones rather than the SOS phones (which clearly know exactly where they are).

[Vierwielen]

London distances only applies to radials of London. It definitely doesn't apply to: M56, M62, M66, M67, M74, A1(M), etc.

I've updated the Wiki page to expand on this.

My understanding is that driver location signs (the big blue ones) are only used in England, not in Scotland, Wales or Northern Ireland. However the standard location marker posts are used in all parts of the UK. Anybody from Scotland, Wales or Northern Ireland care to comment?

Also, anvbody from RoI care to comment what is used there?

[nowster]

These signs should prevent that sort of silliness when people use their mobile phones rather than the SOS phones (which clearly know exactly where they are).

Often the phones themselves don't know where they are... They're supposed to send a stream of DTMF digits as part of the call setup, but not all are correctly programmed. Also, the entire emergency phone network along a stretch of motorway is a single party line. If two phones are off-hook at once, neither will work, as there's not enough line-borne power to run more than one phone.

[Vierwielen]

These signs should prevent that sort of silliness when people use their mobile phones rather than the SOS phones (which clearly know exactly where they are).

Often the phones themselves don't know where they are... They're supposed to send a stream of DTMF digits as part of the call setup, but not all are correctly programmed. Also, the entire emergency phone network along a stretch of motorway is a single party line. If two phones are off-hook at once, neither will work, as there's not enough line-borne power to run more than one phone.

If nowster has proof of this (rather than having heard it as possibly urban legend), then it is worth a letter to his MP as the Highway Coode (http://www.direct.gov.uk/en/TravelAndTr ... /DG_069863) has a whole paragraph on using emergency phones, but nothing on the use of driver location signs.

[Haydn1971]

If nowster has proof of this (rather than having heard it as possibly urban legend), then it is worth a letter to his MP as the Highway Coode (http://www.direct.gov.uk/en/TravelAndTr ... /DG_069863) has a whole paragraph on using emergency phones, but nothing on the use of driver location signs.

]

Proof that the phones are simple devices ? I was tasked with checking them on the A42 once a week on my way into work, the noise on the line and the sheer noise from the busy dual carriageway made them useless. I suspect the current generation of roadside phones are better, the comms upgrades suggest new line technology, digital perhaps ? perhaps even IP based, so locations would be known - perhaps one of our comms or control centre members could clarify ?

As to a paragraph in the Highway Code - The code needs to be simple so that people remember the important parts. When a call is made to the emergency services, they will ask for which motorway you are on, which direction and which junction you have passed, the calls comming in afterwards focus the detail, which is why its important to call a serious accident in, even if you think that the 999 service will know about it.

In general, the fire service in South Yorkshire will dispatch an appliance to a junction each side of the assumed location of the accident and make a pass each way, because many people don't know the direction they are travelling in. Its fair to suggest that this would be standard fire service proceedure.

The driver location signs tie into the marker posts, I'm aware that South Yorkshire Fire Service have always had a motorway map with marker post details, its no great leap to suspect the police have one too. Should there be some confusion over location, whilst appliances are on the way, the control room will contact the local HA control room or police to get a clearer indication of location... The driver location signs are just an extra layer of information that may be of use once the first responder is at the incident.

[wrinkly]

My understanding is that driver location signs (the big blue ones) are only used in England, not in Scotland, Wales or Northern Ireland. However the standard location marker posts are used in all parts of the UK. Anybody from Scotland, Wales or Northern Ireland care to comment?

As far as I know that's true. The last time I was on the M4 in Wales was before DLSs were invented, but I've driven on various Scottish motorways in the last couple of years and not seen DLSs. The stuff about the A74(M) in the Wiki DLS page should really only refer to marker posts.

Perhaps it should be organised as two pages, with the one on DLSs referring to the one on marker posts for anything that applies to both.

[nowster]

If nowster has proof of this (rather than having heard it as possibly urban legend)...

I got talking once to the guy who fixed the SOS phone database a few years ago. Apparently it used to crash several times a day because of the unset phone serial numbers.

[michael769]

My understanding is that driver location signs (the big blue ones) are only used in England, not in Scotland, Wales or Northern Ireland. However the standard location marker posts are used in all parts of the UK. Anybody from Scotland, Wales or Northern Ireland care to comment?

I have yet to see a DLS north of the border. Marker posts are pretty commonplace, though there are plenty of bits where many are missing.

Often the phones themselves don't know where they are... They're supposed to send a stream of DTMF digits as part of the call setup, but not all are correctly programmed. Also, the entire emergency phone network along a stretch of motorway is a single party line. If two phones are off-hook at once, neither will work, as there's not enough line-borne power to run more than one phone.

May of the folks who I have spoken to who have had reason to use one (My job frequently involves interviewing folks who have been in collisions) report that the operator asked them to read out the numbers on the side of the phone box. I have always assumed that this was how they located them.

I would be surprised if the original 1960 and 70 vintage systems (pre DTMF) had any means to identify themselves to the control room.

[scynthius726]

The stuff about the A74(M) in the Wiki DLS page should really only refer to marker posts.

There is one DLS on the A74(M), on the short section on the English side of the border!

[wrinkly]

Are you sure you're not thinking of the chopsticks sign that marks where M6 becomes A74(M)?

It would be very odd to have a DLS on the A74(M) in England when there are none on the top bit of the M6.

[ScottB5411]

Are you sure you're not thinking of the chopsticks sign that marks where M6 becomes A74(M)?

It would be very odd to have a DLS on the A74(M) in England when there are none on the top bit of the M6.

There is one there for the A74(M), just before the A6071 bridge, GSV isn't upto date. 504.1 if IIRC

[ScottB5411]

It would be very odd to have a DLS on the A74(M) in England when there are none on the top bit of the M6.

Yes there is

[wrinkly]

Must be new then. There were none when it was first upgraded to motorway less than 2 years ago. But the marker posts showed M6 and either A or B as if they were mini-DLSs.