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Full Version: What is the deal with Variable speed limits?
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Soadfan1
I have been driving along the m25 a lot recently and see sections of road with variable speed limits, particularly the north west, north and east sections.

I will be driving happily along at 70 when seemingly for no reason at all there is a big 60, 50 or 40 in a red circle above the lanes. It feels extremely weird to slow down to these speeds as no-one around me is paying any attention to them and there is nothing in front of me. I try to slow down to match them but then I get people piling up behind me and shooting past, still doing 70+. Is there something I dont know about these, and are there no cameras for them or something? Or are they left on after an incident or something as there seems no point in them.

Thanks.
peterguk
The cameras may or may not be active. But like all speed limit signs, you ignore at your own risk. Simples.
Stoofa
The conspiracy theorists will tell you that the variable speeds appear as a way to generate even more income for the police.
Whereas in reality they tend to come on for a reason - debris in the road, workers at the side of the road, an incident miles in the distance - where a reduction in the speed of vehicles makes things safer or gives teams time to sort out issues etc.
I've been in the same situation - I drop to the speed limit, many people don't.
They are on camera and you can only assume they have a nice fine & points waiting for them when they get home.
Soadfan1
Maybe but I fail to believe that many people would just flout the limits unless they knew something. Its not like you see that many flouting the 40 or 50 limits at that speed on other roads. Are there fixed cameras on the m25? I have never seen one.
Fredd
QUOTE (Soadfan1 @ Wed, 28 Sep 2016 - 14:03) *
Maybe but I fail to believe that many people would just flout the limits unless they knew something.

Your faith in most people's ability to make independent decisions rather than go along with the herd mentality is touching, but not obviously supported by much evidence. In fact I'd suggest that your willingness to believe that those other drivers possess some superior knowledge to yourself, rather than what they vaguely remember some bloke in the pub telling them about variable speed limits, tends to support a rather cynical view.
Jlc
QUOTE (Soadfan1 @ Wed, 28 Sep 2016 - 14:03) *
Are there fixed cameras on the m25? I have never seen one.

You're kidding right? There's a mix of HADECS 2 (gantry), HADECS 3 (side of road) and SPECS (average). I would not personally speed on the M25.
Soadfan1
One thing that also made me wonder with regards to whether or not you can get caught from these limits is what happens to those cars who pass the gantry before the limit turned on, only for it to then turn on(or lower) without them having a clue? as they are not so regular in distance as to make that scenario impossible, indeed that must almost certainly happen all the time. Or do they have a delay between turning on and cameras activating?
baroudeur
QUOTE (Soadfan1 @ Wed, 28 Sep 2016 - 14:46) *
One thing that also made me wonder with regards to whether or not you can get caught from these limits is what happens to those cars who pass the gantry before the limit turned on, only for it to then turn on(or lower) without them having a clue? as they are not so regular in distance as to make that scenario impossible, indeed that must almost certainly happen all the time. Or do they have a delay between turning on and cameras activating?



Yes. Some cameras are capable of photographing the gantry speed limit and the offending car at the same time.
Soadfan1
Ah ok I did wonder.

I almost always slow down for these signs but its quite likely I have done 5-10 mph above them in the past ( Im not usually one to follow the pack of drivers, but when every single person ie hundreds seem to be going faster you do start to wonder) I mean there must have been a dozen going past the 40 and 50 at at least 70+ in that minute alone.
peterguk
QUOTE (Soadfan1 @ Wed, 28 Sep 2016 - 14:46) *
One thing that also made me wonder with regards to whether or not you can get caught from these limits is what happens to those cars who pass the gantry before the limit turned on, only for it to then turn on(or lower) without them having a clue? as they are not so regular in distance as to make that scenario impossible, indeed that must almost certainly happen all the time. Or do they have a delay between turning on and cameras activating?



IIRC, there is a 40 second delay between new limit being displayed and enforcement commencing.
fedup2
QUOTE (Soadfan1 @ Wed, 28 Sep 2016 - 15:11) *
Ah ok I did wonder.

I almost always slow down for these signs but its quite likely I have done 5-10 mph above them in the past ( Im not usually one to follow the pack of drivers, but when every single person ie hundreds seem to be going faster you do start to wonder) I mean there must have been a dozen going past the 40 and 50 at at least 70+ in that minute alone.




If you drive through one of the 50 restrictions just under the speed limit say 48 then correct that for a true speed,often speedo's are about 4mph fast making your true speed now just 44mph.Then you judge others passing you who are aware of the speedo inaccuracy AND that true speeds under 10%+2 mph wont generate a ticket you then have vehicles passing doing 56mph which is 12mph faster you and that can appear fast.
Jlc
QUOTE (peterguk @ Wed, 28 Sep 2016 - 15:26) *
IIRC, there is a 40 second delay between new limit being displayed and enforcement commencing.

The specific delay is often mentioned in the relevant traffic order. Usually a bit lower than 40s.
peterguk
QUOTE (Jlc @ Wed, 28 Sep 2016 - 20:19) *
QUOTE (peterguk @ Wed, 28 Sep 2016 - 15:26) *
IIRC, there is a 40 second delay between new limit being displayed and enforcement commencing.

The specific delay is often mentioned in the relevant traffic order. Usually a bit lower than 40s.


Thanks.

The point being it answered the OP's question regarding drivers not being able to adjust speed in time for limit change.
Jlc
Indeed biggrin.gif
roythebus
Only yesterday evening the limits dropped to 60 before Bell End Tunnel for about 3 miles, then just before the tunnel back to NSL. Nothing in the road, no sign of anything in the road.

Wrong information is as useful as no information. When you come across this, email Highways England and complain about it. I do.
peterguk
QUOTE (roythebus @ Thu, 29 Sep 2016 - 19:49) *
When you come across this, email Highways England and complain about it. I do.


Then what happens? Nice reply justifying their actions? Compensation?
Churchmouse
Worse is when the variable limit is illuminated and then the next two VSL gantries are blank--only for the following one to display the NSL symbol. Most people seem to assume the blank gantry signs mean that the reduced limit no longer applies, but then there would be no reason to display NSL symbols at all. The only compensation is that the gantry cameras (if any) are allegedly linked to the VSL displayed on the sign, so no VSL displayed should mean no enforcement (of the VSL). But, I don't trust them. dry.gif

--Churchmouse
peterguk
QUOTE (Churchmouse @ Fri, 30 Sep 2016 - 10:22) *
Most people seem to assume the blank gantry signs mean that the reduced limit no longer applies


Yet on non-motorways, they will happily abide by 40mph or 50mph terminal signs on a NSL road, and if they then see a sign post with no sign attached don't automatically it's NSL again. sad.gif
The Rookie
QUOTE (roythebus @ Thu, 29 Sep 2016 - 19:49) *
Only yesterday evening the limits dropped to 60 before Bell End Tunnel for about 3 miles, then just before the tunnel back to NSL. Nothing in the road, no sign of anything in the road.

Wrong information is as useful as no information. When you come across this, email Highways England and complain about it. I do.

Or the incident ahead they were slowing the traffic to avoid congestion had cleared and the system had worked exactly as it was meant to.....either is as likely to be true.
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