I’ve always found the variable limits on the M25 to work well – but the ones on the M42 are often daft (suggesting a lowered speed when there’s not actually that much traffic, and actually creating congestion). It may be a difference in the times I use each one, but I think it’s a difference in implementation

But if they’re changing the limit a couple of miles before the congestion then it would look like that, wouldn’t it?

I’ve always found the variable limits on the M25 to work well – but the ones on the M42 are often daft (suggesting a lowered speed when there’s not actually that much traffic, and actually creating congestion). It may be a difference in the times I use each one, but I think it’s a difference in implementation.

It could be that even with the new signs the motorway is still over it’s (now higher) capacity but only in specific zones. So they manage the traffic as much as they can until a queue inevitably forms.

The speed is reduced when the traffic is seeminly clear as the traffic manager can see that the sum of the cars coming down the motorway, plus the cars joining at upcoming junctions is higher than the capacity of the road. So they slow down the cars approaching and reduce the number cars joining using the slip road lights in attempt to stop the number of cars on the road road exceeding its maxium flow rate (cars per hour). However if there are still too many cars after they have used all their tools then a queue will still form.

To the observer in a car approaching the congestion zone all they see is speed limits and then a queue and spot the correlation between speed limits and queues and jumped to conclusions, but what they have failed to realised is that the queue and the speed limit had the same root cause, the predicted volume of traffic, the speed limit will have actually reduced the severity of the queue but this is not apparent.

Is there any research on banning lane changing too? Ie preventing lane hopping, reckon stopping that could improve throughput too

I believe it has a similar effect.

IIRC any kind of “disruption” to “perfect traffic flow” will introduce one of these caterpillar wave thingummies. Disruptions include anything – lane changing, unnecessary speedup/slowdown, junctions, lanes merging, etc…

suggesting a lowered speed when there’s not actually that much traffic, and actually creating congestion

I think you’ve just neatly made the point about drivers not being able to be aware of the whole road network and how they thusly can’t anticipate the required speed limits for maximum traffic flow. We can’t seeing the wood for the trees, etc.

Is the M1 really near Matlock? I never knew that!

Is the M1 really near Matlock? I never knew that[/QUOTE]

If you count 10 miles as near then yes

Thing is, without any viable and practical alternative to travel by private motor vehicle, all these schemes do is move the congestion somewhere else. So yes, they will almost certainly claim that the scheme “reduced pollution” or whatever, but in fact, next year, there will still be more cars in the road and more congestion…………

Thing is, without any viable and practical alternative to travel by private motor vehicle, all these schemes do is move the congestion somewhere else. So yes, they will almost certainly claim that the scheme “reduced pollution” or whatever, but in fact, next year, there will still be more cars in the road and more congestion…………

Plenty of alternatives, just whether you think they are viable and that isn’t the same as being viable.

And if you want to get rid of congestion there is only one solution, make driving a pain in the arse that no one in their right mind would do.

make driving a pain in the arse that no one in their right mind would do.

that’s a rather negative view point. The better solution is to have more viable alternatives so that using the car isn’t the obvious choice for most.

Of course, that probably requires investment in most cases but if we spent money on that rather than more roads…

As has been posted before speed cameras will be installed which will catch unawares motorists and MAKE MONEY.

The correct solution is to install variable speed limits at peak hours.

We all need to be very aware that “environmental concerns” is the new political catch all to justify things which have no relation to protecting the environment.

This isn’t just related to the UK, the same is being done elsewhere, the speed limit on the Paris Peripherique is being cut from 80 to 70kmph for “environmental reasons”

The correct solution is to install variable speed limits at peak hours.

enforced by speed cameras?

As has been posted before speed cameras will be installed which will catch unawares motorists and MAKE MONEY.

How can you be unaware?

Or do you have information that the speed limit signs will have a big quesion mark and it’ll be like a lottery so you have to guess the limit and you get a fine if you guess wrong and go too fast?

If it’d get everyone driving at consistent speed and stop the cascade traffic jams then I’d be all for average speed cameras and variable speed limits along every major road.

my office window looks out onto the M1 – half a mile south of J33.

it’s 4.47pm, and already traffic is proceeding such that a 60mph limit would inconvenience no-one at all.

question: is it the heavy traffic, or the fast traffic that’s causing the air pollution?

(they seem to be approximately mutually exclusive)

As has been posted before speed cameras will be installed which will catch unawares motorists and MAKE MONEY.

Again – why is this a bad thing?

BECAUSE OF THE WAR ON MOTORISTS!!!!!!!!!!!!!!!!!!!!!!!

question: is it the heavy traffic, or the fast traffic that’s causing the air pollution?

Both, but only the fast traffic’s pollution will be reduced by this measure.

If it’d get everyone driving at consistent speed and stop the cascade traffic jams then I’d be all for average speed cameras and variable speed limits along every major road.

This is the only way. The issue with the current speed camera’s is that they encourage people to brake heavily, then speed up. Bad for congestion and pollution.

But people are incredibly resistant to them as very few people want to drive at 60/70 when the roads are empty. I’d agree with this, trolling along that slowly on an empty road is infuriating.

It seems a fairly open secret that the speed camera’s on the M1 between 25 and 28 are only active when then variable speed limit is enforce. I don’t know why this couldn’t be publicised and average speed camera’s used to control speed only when the temp speed limits are in force. The aim of this being to reduce congestion, not dangerious driving.

The police can then target dangerous driving when the camera’s are off if they want with other more effective methods than static speed camera’s

I wonder what the effect would be of reprogramming all traffic lights in the UK to go on ‘flashing amber’ (proceed with caution) when not in rush hour could have on pollution rather than focus on one 32 mile stretch of one motorway?

I am sick of stopping at red lights at 2am whilst the set goes through its sequence. They do this in other parts of the world I believe?

Just a thought.

I hope these jeb ends don’t get this through! Either it’s so busy you can’t get up to 60 or it’s clear and then you’ll be stuck doing 60!

As for reducing pollution if this does come into effect I’m going to drive through in 3rd gear increasing the amount of pollution my car gives out! Seen as I have a company car and pay per mile and not fuel used it won’t cost me any extra to teach them a lesson!

Teach them a lesson? Wtf are you talking about? Have a word with yourself.

Do I need to draw you a diagram sweetheart?

Their doing it to cut pollution apparently! So I’ll lay the smack down on them by busting out more pollution doing 60 in 3rd gear than 70 in 5th! Simples!

Stick it to The Man!

Meanwhile, on my 5min 37sec walking commute, I saw a Robin.

Their doing it to cut pollution apparently! So I’ll lay the smack down on them by busting out more pollution doing 60 in 3rd gear than 70 in 5th! Simples!

You’re being ironic, I assume…

I think he’s just a moron…

I’m not sure about anyone else but I’m so turned on by enduroganster right now, I wonder if he’d let me have sex with him?

I’m available if endurogangster isn’t feeling the love. 🙂 ❓

Say something twatish and I’ll see if I can get another semi on.

I can do 60 in second in my car. ❓

The planned Manchester M60 Managed Motorway scheme has been binned on health grounds. A report has suggested it will lead negative impact on air quality.

Highways Agency scrap M60 managed motorway

OMG – this takes me back to Littles Law and M/M/1 models 😆

Variable speed limits on M1 between J24 and J28. I travel north from J25 to J27 when driving to work and most mornings the southbound traffic is congested. But the signs are lit and woe betide speeders as I have seen the GATSOs flash many-a-time.#

Personally I’m looking forward to self-driving cars. Congestion would reduce drastically, fewer accidents and I can relax going to and from my MTB meets. 😀

It works on the M25 and M42 so why not?

A word to the wise. The new cameras on the M62 are set really low. Below 80 I’ve been told by my brother-in-law who works for HA. Don’t give the ba@ta*ds anymore money!

Basically the HA have committed £100+ million to the ALR scheme between J28 and J35. The pollution problem has been holding up the scheme at great cost to themselves. This mandatory 60 from 7-7 will mean they can go ahead with the scheme as they can bring the final pollution level down to an acceptable level.

who will benefit from this reduced pollution?

Good question. This is all well and good for people who breathe air and live somewhere within the earth’s atmosphere, but what is it going to do for me?

it was a genuine question. why do it locally and not across the road network? is there a particular problem in that area due to the concentration of roads/ people?

I travel J36/J35a to J33 every weekday, the central barrier replacement roadworks have now gone but there was no notable effect on my journey time when they and the accompanying 50mph limit was in place. I’m sure having all 3 lanes live across Tinsley viaduct would help with average speed/traffic volumes/pollution levels but it would seem that particular structure was so badly designed it simply can’t be fixed.

As has been posted before speed cameras will be installed which will catch unawares motorists and MAKE MONEY.

You can post something a hundred times but it doesn’t make it true.

I think you’ve just neatly made the point about drivers not being able to be aware of the whole road network and how they thusly can’t anticipate the required speed limits for maximum traffic flow. We can’t seeing the wood for the trees, etc.[/quote]

Except when I drive on the M42 I always drive end to end of the managed section and the majority of the time end to end of the M42, and the occasions I’m complaining about there isn’t any downstream queuing or any signs of conditions which might result in it. I’m fairly confident I’m not missing anything and that higher speeds wouldn’t result in congestion – I’ve got quite a bit of experience of driving on motorways at various states of congestion, an it is possible to be aware of what causes it. Remember I’m comparing with my experience of driving through the similar section on the M25, where at similar traffic levels the speed limits aren’t lowered.

I agree that managed speed limits on motorways can work well – the section on the M6 I use fairly frequently also works well, it just seems to be the M42 where the algorithms used are screwed.

I’m not sure about anyone else but I’m so turned on by enduroganster right now, I wonder if he’d let me have sex with him?

You don’t have sex with endurogangster! You strap yourself in and experience the G’s!

Lower speed will mean less noise.
I saw a programme about the noise levels on the A4 which are horrendous. That’s why it’s 40 mph.
They were talking to an old guy who said the noise was intolerable. I immediately thought “why did you move there?”
They then showed a picture of the road when he moved in. It looked like a country lane.
So peoples cut your speed and give the poor sods who live near these roads a better standard of life.

that’s a rather negative view point. The better solution is to have more viable alternatives so that using the car isn’t the obvious choice for most.

there’s also evidence to show making the alternatives just as good as car travel doesn’t work, everyone has a car outside their house ready to drive, you also have to gimp the private car option to make the public transport look a lot better. Trouble is we appear to be doing neither, war on the motorists means no significant beatdown on the poor old motorist whilst investment on none private travel infrastructure is a bloody waste of all that fuel duty revenue.

Don’t give the ba@ta*ds anymore money!

They aren’t bastards, they’re the police, and they look after us. You’d be the first person moaning about police funding if they didn’t have enough resources to find the person who stole your bike, for example.