Are the "orange speed signs" mandatory?

[mikdys]

I was thinking aoubt this last night travelling down the M40 at about 11pm. Not much other traffic about, good road surface and good visability. No sign of any roadworks or other problems yet the "orange signs" were on 50mph. The temptation to keep going at 70 was very strong (all other traffic was doing this!) but what would have happened if I had been caught doing this also?

Anyone know the answer?

BTW I know the chances of being pulled for this are slim but I don't want to risk any points at all just now!

[CommanderJameson]

They're advisory.

The ones you may encounter on the south and west quarters of the M25 are mandatory, and have a red ring to indicate this.

Red is a good indicator of mandatoriness. Red flashers or a red X (for a lane closure) are mandatory.

[s2ooz]

This also applies to those signs often used on tight bends "warning - 30mph"
they are advisory.

They will not have a NSL sign after them to enable you to regain speed. No red ring, not mandatory.

[Flat in Fifth]

s2ooz said:

This also applies to those signs often used on tight bends "warning - 30mph" they are advisory.

All very true but they might just give you the heads up that something ahead is a bit different.

Example M5 -Northbound J4
You get sharp bend to left and advisory 50 mph.

Junction so off and on slips. The on slip is hidden round the bend and is also quite steep so you only get a view of joining traffic at the last minute.

Add in the absence of a hard shoulder.

So what would all the clever chaps on here do?

Personally I peg it back and establish a position to get best view possible considering other traffic and conditions generally.

Would you? Observation of reality says most don't, rather like salmon leaping over that weir.

[Peter Ward]

Flat in Fifth said:

s2ooz said: This also applies to those signs often used on tight bends "warning - 30mph" they are advisory. All very true but they might just give you the heads up that something ahead is a bit different. Example M5 -Northbound J4 You get sharp bend to left and advisory 50 mph. Junction so off and on slips. The on slip is hidden round the bend and is also quite steep so you only get a view of joining traffic at the last minute. Add in the absence of a hard shoulder. So what would all the clever chaps on here do? Personally I peg it back and establish a position to get best view possible considering other traffic and conditions generally. Would you? Observation of reality says most don't, rather like salmon leaping over that weir.

It may be that most drivers ignore these signs because there are just so many of them that cry wolf. That's the problem with plastering warnings everywhere -- the impact wears off so the real ones get ignored as well. Speed limits happen to be another example of overusing a tool so that its effect in important places declines.

[7db]

I can make neither rhyme nor reason of the use of the motorway advisory boards. Some of the time there's a genuine queue, other times, there is nothing at all.

Natural reaction is to press on till the queue and join it.

The boards with messages are worse. Why do I care about Jn 15 (and where is it?) on the M1, whilst at Jn 8 of the M4?

Fixed advisory signs can be useful where they advise of possibly unsighted hazards, and you can read them like any other part of the road to give clues as to hazards. For particularly sharp or unsighted bends, with junctions, or short areas which might be considered for mandatory limits, I think these are a thoroughly good idea.

[Flat in Fifth]

Peter Ward said:

It may be that most drivers ignore these signs because there are just so many of them that cry wolf. That's the problem with plastering warnings everywhere -- the impact wears off so the real ones get ignored as well. Speed limits happen to be another example of overusing a tool so that its effect in important places declines.

I know said the same thing myself many a time, white paint is another overused example.

However...... I do believe that drivers ignore the signs never having raised their vision and looked for the other observations and following links which might forewarn and thus forearm them of a potentially difficult situation. Actually to be honest I think many drivers don't even see the signs in the first place.

FiF

[BliarOut]

Peter Ward said:

Flat in Fifth said: s2ooz said: This also applies to those signs often used on tight bends "warning - 30mph" they are advisory. All very true but they might just give you the heads up that something ahead is a bit different. Example M5 -Northbound J4 You get sharp bend to left and advisory 50 mph. Junction so off and on slips. The on slip is hidden round the bend and is also quite steep so you only get a view of joining traffic at the last minute. Add in the absence of a hard shoulder. So what would all the clever chaps on here do? Personally I peg it back and establish a position to get best view possible considering other traffic and conditions generally. Would you? Observation of reality says most don't, rather like salmon leaping over that weir. It may be that most drivers ignore these signs because there are just so many of them that cry wolf. That's the problem with plastering warnings everywhere -- the impact wears off so the real ones get ignored as well. Speed limits happen to be another example of overusing a tool so that its effect in important places declines.

There's one on a sliproad to the M6 says 35.... It can comfortably (And legally) be taken at 70

[7db]

If I recall correctly the speeds are set so that the cornering force required is 0.2g. Since your tyres can probably comfortably handle 1g in the dry, going twice as fast (f=mrw^2) ought not to impinge on the limits of grip.

You might, however, be well past the limit of visibility, and if some of your grip is being used for braking, accelerating or balancing the yaw rate, then you could still get into trouble (ie complete the curve facing a different way from the way you entered).

[pdV6]

The BiB will probably slate me for this, but in my experience, orange matrix boards giving temporary advisory speed limits seem to be actually relevant to me less than 1% of the time.

As has been mentioned, constant exposure to meaningless warnings has eroded my respect for them, so that now I take them as a "heads up" that something might be up but in all likelihood probably not.

I can recall only one time in my driving career (17+ years and many 100s of thousands of motorway miles) when a "50" matrix actually meant a severe problem ahead. In this instance, a lorry had crossed the central reservation and shed its load such that all 6 lanes of the M4 were blocked. Arguably, a "50" sign was about as much use as a chocolate teapot but a clear-thinking trafpol had run back up the hard shoulder waving a high viz vest, thus avoiding a pile up. I would have thought that "TTT" would have had a better effect on traffic than "50"; I wonder why m/way control hadn't flashed that up instead...


On another tack, I passed through some roadworks last weekend (50 limit) and 1/2 way through, a random matrix board was displaying "End". I wonder how many people took that to mean "end of 50 limit" and got pinged as a result?

[Dwight VanDriver]

Signs are the langwidge of the rode Fif....not everybody has your Komprehenshion so the Janets and Johns have to be catered four.....

dvd

[7db]

Only lane closures, and limits with red circle -- regardless of if overhead or on stalks in centre.

[mikdys]

Thanks for you replies

[Big Fat F'er]

Flat in Fifth said:

Actually to be honest I think many drivers don't even see the signs in the first place.

Which is why it's so funny to hear some complain about getting caught on a road with streetlamps, and a 30mph sign, and big white lines, and a sodding massive yellow box.

Not only should you get done, you should be banned for driving whilst blind.

[parrot of doom]

BliarOut said:

There's one on a sliproad to the M6 says 35.... It can comfortably (And legally) be taken at 70

Hmmm, not the one from Stoke me thinks!

[Pigeon]

7db said:

If I recall correctly the speeds are set so that the cornering force required is 0.2g. Since your tyres can probably comfortably handle 1g in the dry, going twice as fast (f=mrw^2) ought not to impinge on the limits of grip.

[pedant] Linear velocity, not angular, so (mv^2)/r (still got a velocity squared term on top though) [/pedant]

I find that while most of the bend warning signs are a bit overdone, there is the odd one that is reasonably accurate, so it's worth taking note of them when I don't know the road. The ones on off-ramps are also a useful reorientation device for the transition from high speed with very little curvature to low speed wiggly bits - a reminder that the "sense of feel" needs to be reset.

[streaky]

Big Fat F'er said:

Flat in Fifth said: Actually to be honest I think many drivers don't even see the signs in the first place. Which is why it's so funny to hear some complain about getting caught on a road with streetlamps, and a 30mph sign, ...

Where there is street lighting, a 30 sign may well not be required and its presence could indicate errors in other signage and introduce questions of legality about the limit - Streaky

[7db]

Pigeon said:

[pedant] Linear velocity, not angular, so (mv^2)/r (still got a velocity squared term on top though) [/pedant]

[mathmo pedant]That's "speed", not "linear velocity" if you want to use v in that context, otherwise its v.v; not v^2.

Whilst the angular speed equations are right, and show that if you go round the corner twice as fast, the force doubles, I acknowledge that one probably does want to use speed (rather than w) as that is what the advisory signs refer to - ie drive the corner twice as fast rather than go round it twice as fast).

I prefer the w formulation as it avoids typing fractions. Notice that f is used to denote the magnitude of the net force on the vehicle f[/mathmo pedant]

Thanks for your point, though.

[Flat in Fifth]

Dwight VanDriver said:

Signs are the langwidge of the rode Fif....not everybody has your Komprehenshion so the Janets and Johns have to be catered four..... dvd

Sithee!

You are too kind but.......

From this am performance at location described above.

Add in matrix signs flashing queue ahead, add in a phalanx of brake lights from stationary traffic ahead.

Judging by the lemming like rush seems to me Janet and John speak Serbo-Croat, if yer knows what I mean guvnor.

FiF

[g_attrill]

Hmmm.... the HC is as vauge as ever:

www.highwaycode.gov.uk/signs01.htm

Temporary maximum speed limit

However the TSR&GD is more specific:
www.opsi.gov.uk/si/si2002/023113gl.gif
"Temporary maximum speed advised"

Gareth