Matrix board not displaying variable speed limit

[qwertyK]

Today on the M11 they have variable speed limit boards, very old ones I think they're from the 70s and 80s when the road first opened.
Showed 50 just near the turn off for the A11 heading north, so I slow down accordingly.
Next board I pass there's no speed limit shown on it, so I assume it's back to NSL as the road was clear, so I get up to 70-73mph.
Next board I pass just shows "End"
So it worries me that I was going 20mph over the tempoary speed limit but i didn't know that as nothing was shown on the next board. Other drivers too were doing the NSL.
What would your rights be here?

Set me thinking. If we were to change to km/h, which variable speed limit boards could easily be changed to show 100 km/h and which ones could not?

The MS1 and old boards like the one I'm talking about almost certainly couldn't, I suspect the smart motorway ones could though? Maybe not

[Ishtaria1980]

No idea but I hit the traffic coming southbound wasn't a continuous queue just pockets around the Essex-Cambs border at the A11, Stansted/A120 and the m25 . Mind you there's always traffic at the m25 junction .poorly designed junction IMO to have two lanes going towards London but just one for the m25.

Same as with the M1 to the M25. I simply cannot fathom why they can't have the lane 1 drop then allow lane 2 to junction on like they do with pretty much most other LILO motorway junctions

[Bomag]

Today on the M11 they have variable speed limit boards, very old ones I think they're from the 70s and 80s when the road first opened.
Showed 50 just near the turn off for the A11 heading north, so I slow down accordingly.
Next board I pass there's no speed limit shown on it, so I assume it's back to NSL as the road was clear, so I get up to 70-73mph.
Next board I pass just shows "End"
So it worries me that I was going 20mph over the tempoary speed limit but i didn't know that as nothing was shown on the next board. Other drivers too were doing the NSL.
What would your rights be here?

Set me thinking. If we were to change to km/h, which variable speed limit boards could easily be changed to show 100 km/h and which ones could not?

None, as you cannot fit '100' at the presibed text size in a roundel of the prescribed diameter. You would always end up with a smaller size than is considered clearly readable.

[Nicola_Jayne]

So can the matrix boards you see on central reservations ever show mandatory speed limits or only ever advisories ?

In all honesty I probably would have continued at 50 but the road was clear and I was **** people off even in lane 1 of 2

traditional Matrix oin the central reeservation - speeds shown on them entirely advisory

not sure if there are any central reservation matrix able to show the correct pictogram for an enforceable speed limit

[nowster]

Set me thinking. If we were to change to km/h, which variable speed limit boards could easily be changed to show 100 km/h and which ones could not?

When they converted to metric speed limits in Ireland, they narrowed the number font.

I'm sure the MS1s could be adapted by changing the bitmap for the matrix, just like Ø became "End". However advisory limits on them normally max out at 50 mph, which is 80km/h.

[Bomag]

Set me thinking. If we were to change to km/h, which variable speed limit boards could easily be changed to show 100 km/h and which ones could not?

When they converted to metric speed limits in Ireland, they narrowed the number font.

I'm sure the MS1s could be adapted by changing the bitmap for the matrix, just like Ø became "End". However advisory limits on them normally max out at 50 mph, which is 80km/h.

Even with a 20mm dot pitch, a bi or tri coloured LED panel (needed for enforcement) would have difficulty squeezeing the font.

[nowster]

I'm sure the MS1s could be adapted by changing the bitmap for the matrix, just like Ø became "End". However advisory limits on them normally max out at 50 mph, which is 80km/h.

Even with a 20mm dot pitch, a bi or tri coloured LED panel (needed for enforcement) would have difficulty squeezeing the font.

If you can get the wicket gate on an MS1, you can get the numbers 100, 110 and 120 on it. The matrix seems to be 11×11.

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[nowster]

Someone on Wikipedia has mocked one up already:
https://commons.wikimedia.org/wiki/File ... it_120.svg

And that's based on page 14 (Sheet 5 of Drawing MCX 1022) here: https://www.standardsforhighways.co.uk/ ... nline=true

[tom66]

Set me thinking. If we were to change to km/h, which variable speed limit boards could easily be changed to show 100 km/h and which ones could not?

I think only the MS4's could do so and even then that would be a stretch*.

Say you need to display up to 120 kph. Well the existing AMI units have a 32x32 pixel resolution, but the current characters are approximately 14 x 28 for legibility and the sign has a 'dead pixel avoidance' algorithm where characters are moved around to avoid dead pixels.

So just on that basis unless you go for a narrow font you can't fit anything above 90 kph. Note that showing just a single vertical bar for '1' isn't enough. The '1' has a tip and 'feet' to distinguish it. So you need at least a few extra pixels. You could just compromise and say that 120 is NSL and 90 and below are VSL. But that means you lose the '60 mph' running that current smart schemes enjoy.

*The secondary issue is the AMI's and MS4's are not arbitrary graphic displays but character-glyph addressed, using some proprietary Highways RS485 interface. So they just don't have glyphs to support what you'd want. This goes back to some of the original digital displays using halogen lamps. The software would need to be updated on all of these units - no idea if this can be done remotely or if it would require every sign to be refurbished.

[nowster]

Set me thinking. If we were to change to km/h, which variable speed limit boards could easily be changed to show 100 km/h and which ones could not?

I think only the MS4's could do so and even then that would be a stretch*.

See the standardsforhighways drawings PDF I linked to above (also attached below as PNG). The glyphs are probably already in the hardware in recent units built since 2001.

[tom66]

Set me thinking. If we were to change to km/h, which variable speed limit boards could easily be changed to show 100 km/h and which ones could not?

I think only the MS4's could do so and even then that would be a stretch*.

See the standardsforhighways drawings PDF I linked to above (also attached below as PNG). The glyphs are probably already in the hardware in recent units built since 2001.

Well that sent me down a rabbit hole!

https://www.whatdotheyknow.com/request/ ... 0codes.pdf

Page 19 onwards lists the valid MS1,3,4 and AMI indicators. For whatever reason, the kph ones are omitted from AMIs. So, no capability to display anything above 60 mph (don't know if they could display a 70 mph roundel for Welsh/Scottish special roads?)

So why on earth can MS4s show kph, if AMIs can't? Are the same models used in the EU and this is harmonised, but if so, why were the AMIs not harmonised?

[wallmeerkat]

Surely they would need higher resolution, presumably like Ireland has

I think this shutterstock image is Australia https://www.shutterstock.com/image-phot ... 1124095142

[Chris5156]

The ability to show three-figure speed limits was built in to MS1s in the 1960s, in anticipation of a change to metric speed limits.

Sheesh, doesn’t anybody read Roads.org.uk any more?

[tom66]

The ability to show three-figure speed limits was built in to MS1s in the 1960s, in anticipation of a change to metric speed limits.

Sheesh, doesn’t anybody read Roads.org.uk any more?

That offers some explanation of why the MS1's have such characters built into them but why on earth the AMIs have them (but do not have the 'mandatory' ones) is baffling. Are we going to introduce metric advisory limits and imperial mandatory limits?

[wallmeerkat]

The ability to show three-figure speed limits was built in to MS1s in the 1960s, in anticipation of a change to metric speed limits.

Sheesh, doesn’t anybody read Roads.org.uk any more?

There's so much good content on that site it's finding it

I see one of the matrix settings is 'GA', I'm trying to figure out which one it would pair with, 'GA TE'?

[nowster]

Sheesh, doesn’t anybody read Roads.org.uk any more?

How did I miss this?!?!

https://www.roads.org.uk/sites/default/ ... ymbols.jpg

[Chris5156]

The ability to show three-figure speed limits was built in to MS1s in the 1960s, in anticipation of a change to metric speed limits.

Sheesh, doesn’t anybody read Roads.org.uk any more?

That offers some explanation of why the MS1's have such characters built into them but why on earth the AMIs have them (but do not have the 'mandatory' ones) is baffling. Are we going to introduce metric advisory limits and imperial mandatory limits?

That I can’t explain! I suppose more recent signal specifications haven’t had the rose-tinted optimism of the sixties. At the time metrication was policy whereas now it’s clearly not on the cards.

There's so much good content on that site it's finding it

I see one of the matrix settings is 'GA', I'm trying to figure out which one it would pair with, 'GA TE'?

I never found anything to explain the words, but yes, I’ve always assumed that pairing was to make GATE.

The two-panel worded messages seem to be:
FOG
GATE
SLOW
STOP
HIGH
WIND

The word WIND was certainly used on the double-panel MS1s deployed to the Severn Bridge, and it’s possible that the signals alternated between HIGH and WIND.

The others I don’t think were ever used: no other double-panel MS1 signals were ever installed, and many of the signal’s capabilities were never used in the end. However, if you assume they could alternate between two different symbols, it’s conceivable that there was an intention to alternate between SLOW and FOG. STOP would obviously work on its own, which just leaves GATE. I don’t have the faintest idea what it might have been for, but there may have been a use envisioned that never happened - such as signals on urban roads leading up to a multi storey car park, where you might warn people STOP GATE as they approach the ticket barrier. We can only guess.

Similarly, I’ve always been intrigued by some of the never-used symbols. One is for two-way traffic, so maybe the idea was that you could run an emergency contraflow; another seems to mean “end of dual carriageway”, which is baffling. I would hazard a guess that the decimals (“0,2” etc) were for double-panel displays, so you could show a hazard or lane closure symbol and a distance to it side by side.

[ROAD ROVER]

Also what on earth was going on with the M11 yesterday? Seemed like there were half a dozen truck that had had blow outs

If they're in the same locality then a lost ratchet strap will be a likely candidate.

[nowster]

The others I don’t think were ever used: no other double-panel MS1 signals were ever installed, and many of the signal’s capabilities were never used in the end.

Glyphs E3 to E6 are Sev, dge, Bri, ern.

I wonder what you can make with them?

[Bomag]

I'm sure the MS1s could be adapted by changing the bitmap for the matrix, just like Ø became "End". However advisory limits on them normally max out at 50 mph, which is 80km/h.

Even with a 20mm dot pitch, a bi or tri coloured LED panel (needed for enforcement) would have difficulty squeezeing the font.

If you can get the wicket gate on an MS1, you can get the numbers 100, 110 and 120 on it. The matrix seems to be 11×11.

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The point was about an enforceable limit, which the MS1 cannot do. You need a bi- or tri- coloured panel to do that and the options are limited. When they wanted to test 55mph limits it did not fit (with required gaps).