RE: 50 limits by the back door: PH Blog

[danwarwick]

As a driver of goods vehicles myself I can say there is nothing more annoying than approaching a 50mph limit with average speed cameras and having lots of cars speed past you and then slam their brakes on for the cameras causing you to end up doing an average speed of around 44-46mph for the full length of the limit. Truck speedos are as far as I know slightly more accurate than the average car speedo and when the car has sped past and slammed it's brakes on to travel at what they think is 50mph because their speedo says so the truck speedo will in most cases be reading around 46mph when following them, certainly not sitting on their 55mph limiter as the author states. Try using a sat nav unit and see what the speed reading is compared to your car speedo.

[funkyrobot]

Kenny Powers said:

saaby93 said:

I dont think anyones complaining about where and when they seem to work eg at the M5 M6 junction at busy times

Its when theyre 'Stupid' rather than Smart eg ethe M42 M40 junction where there often seems to be one gantry out of kilter with the rest and it seems to be congestion causing rather than solving

Then there's the ones set to a speed limit for no apparent reason when there's very light traffic and it makes no difference

If theyre ever going to improve there ought to be a reporting method when theyre wrong - maybe PH is the place?

Fair points. Perhaps in time they will improve as more is learnt. My point is that, to my knowledge, they are about traffic flow, not draconian safety, as so many people continue to want to believe.

The posts in the past from people connected to the highways system have mentioned that they are designed to regulate flow.

Unfortunately, because so many people seem to drive an inch from the bumper of the car in front, if anything happens everyone piles in and you get a queue.

If the system can smooth out the flow of traffic miles back by reducing the speed limit a bit, it should stop the mad pile in and slam on the brakes situations.

I guess the best system is one that makes you wonder why you were even slowed down. It's probably better to cover 3 miles at 50mph, than 2 miles at 70 odd mph and then come to a dead stop at mile 3.

[funkyrobot]

Dan Trent said:

PorkInsider said:

I might be missing something here, but the particular section of the M1 being discussed in the article has some roadside signs - albeit quite small and poorly positioned ones - which read:

REDUCED SPEED LIMIT IN FORCE DURING TECHNOLOGY COMMISIONING

So presumably, even though they've finished the work to get to 4-lane running on that section, they're still fancying around with the CCTV or something?

Or am I missing something else?

Very interesting and your eyesight is clearly better than mine! If that's the case I'll happily eat (some of!) my words!

Dan

As others have mentioned Dan, can't you utilise some PH resources and look into this properly. I.e., get some time with someone from highways or even visit a control centre and get them to explain and show you the reasoning behind these lower limits?

I think it would be a good use of time to follow this up.

[andy43]

danwarwick said:

As a driver of goods vehicles myself I can say there is nothing more annoying than approaching a 50mph limit with average speed cameras and having lots of cars speed past you and then slam their brakes on for the cameras causing you to end up doing an average speed of around 44-46mph for the full length of the limit. Truck speedos are as far as I know slightly more accurate than the average car speedo and when the car has sped past and slammed it's brakes on to travel at what they think is 50mph because their speedo says so the truck speedo will in most cases be reading around 46mph when following them, certainly not sitting on their 55mph limiter as the author states. Try using a sat nav unit and see what the speed reading is compared to your car speedo.

I can set my cruise to an indicated 54-55mph (actual 52-ish) and be sailing past 99% of the traffic.
I'm genuinely not convinced smart motorways work any better than 'normal' roads, and when the gantry speeds keep changing within short distances can actually be dangerous, but I'm sure the smart motorway sales people will have lots of reports and research to prove otherwise...

[saaby93]

funkyrobot said:

I guess the best system is one that makes you wonder why you were even slowed down.

the ones where the traffic is moving ok, then you reach overhead gantries with various combinations of speed limit, as you say it leads to bunching with everyone nose to bumper, than after a couple of miles of stop starting you come to a gantry with NSL on it - it happens to be the last gantry but hey ho - and the motorway is as clear as a bell

What came first the congestion or the gantries?

Good idea about Dan visiting all the control centres at various times of day and night

[tankplanker]

funkyrobot said:

The posts in the past from people connected to the highways system have mentioned that they are designed to regulate flow.

Unfortunately, because so many people seem to drive an inch from the bumper of the car in front, if anything happens everyone piles in and you get a queue.

If the system can smooth out the flow of traffic miles back by reducing the speed limit a bit, it should stop the mad pile in and slam on the brakes situations.

I guess the best system is one that makes you wonder why you were even slowed down. It's probably better to cover 3 miles at 50mph, than 2 miles at 70 odd mph and then come to a dead stop at mile 3.

If they were used sensibly then I would have more time for the variable speed limits, but the one leading up to the M40 junction on the M42 usually goes something like 60 - 50 - 50 - 60 - 40, with the queuing/heavy traffic sitting around the 40 mph gantry and the 60 gantry set just before a bend that those in the outside lane cannot see that the next gantry is 40. As everybody seemingly matches the speed of the car in front as that is easier than speedo watching, and anybody "dawdling" in the outside lane is undertaken (where possible) or aggressively tail gated, so the traffic moves at the exact posted limit plus about 10%.

Now I accept if everybody ignored the speed up section and maintained a steady speed you wouldn't have this problem, however if people were capable of doing that then we wouldn't need the variable speed limits in the first place. Ignoring a sudden lane reduction (accident or road works typically) or junction (on and off) stationary/near stationary traffic on a free flowing motorway is caused by people bunching up and then concertinaing. People changing lanes into heavily bunched up traffic makes this worse as well.

It makes zero sense to increase the speed at the second 60 gantry, yet it has been like that more more than 12 months, and this isn't the only section this happens on. If they could just sort out a steady speed for this section it would make a big difference.

I am also not convinced that the speed limits aren't on an auto timer rather than being manually controlled, thus they aren't really smart at all. I seem to remember somebody posting here from one of the control centres saying that they did not have enough staff to manually monitor everything.

[cookie1600]

German Autobahns

That is all I have to say

[funkyrobot]

saaby93 said:

funkyrobot said:

I guess the best system is one that makes you wonder why you were even slowed down.

the ones where the traffic is moving ok, then you reach overhead gantries with various combinations of speed limit, as you say it leads to bunching with everyone nose to bumper, than after a couple of miles of stop starting you come to a gantry with NSL on it - it happens to be the last gantry but hey ho - and the motorway is as clear as a bell

What came first the congestion or the gantries?

Good idea about Dan visiting all the control centres at various times of day and night

Who knows. I don't have access to highways data to show traffic density and how it is affected by these gantry speed limit changes.

I think that these actions are being undertaken because we are simply running out of space. Attitudes to driving are also different because of modern car technology.

I do believe we are also getting more and more impatient as we are expecting more things to give us what we want, now! There are a lot of angry people on the roads. Probably due to the volume of traffic. We're still driving on a lot of roads that were designed and built ages ago.

Jobs are further away (even though working remotely can be done now), funding of cars is very easy (whether you can really afford it or not), and it is probably now considered the norm to drive 25+ miles to work. Some people are lazy too and will drive minimal distances to work (a chap three doors down from me drives to the building next to mine, that I walk to every day).

Public transport is expensive and where I live, utterly useless (no train to the place I used to work until 9am and the last return was 4.45pm). There are also a lot of people bringing cars over from the continent when they move here.

We are running out of space and I can't see it getting any better.

[funkyrobot]

cookie1600 said:

German Autobahns

That is all I have to say

What's the attitude to driving like in Germany? Are they as bad as most people here? Do they have more room and a better infrastructure for things like this?

Could roads like this really work here? Or would it cause carnage?

[funkyrobot]

Mandown46 said:

Dan, I'm somewhat disappointed.

Last time this was raised, one of my fine colleagues took the time to explain in detail how these work, and made you an offer to get you into the control room, and would have probably been able to get you some time out with the on road patrols too.
He had done this before for groups of PH'ers.
I remember discussing it in private with you as well.

I can only assume you didn't take him up on this, only to see you repeating the rant again is frustrating.

Amazing.

Good old PH, eh. Maybe Dan could take up the offer of a control centre visit now and update us all?

Thanks for the updates. Just proves what I was thinking.

[Jbliss]

Mandown, How do you explain the gantries that display NSL-40-NSL-30!-50-NSL etc When there is nothing more than very light traffic?. Often its at night when its clear there hasn't been an obstruction there for quite some time. I think some people (myself included) have a problem with frankly dangerously low limits on the motorway when there is absolutely no traffic for the next 30 miles. To have someone hit the brakes from NSL to 30 when they reach the gantry is only asking for trouble.

Take the M25/M1 junction. It's like they just leave that section on 50 constantly even in the middle of the day when there simply isn't any need.

Part of the problem is that there is no section of the driving test that covers motorways. The standard of driving is shocking.

[cookie1600]

funkyrobot said:

Could roads like this really work here? Or would it cause carnage?

Doubtful as I don't think we actually have the space or public finances to create a system that would enable faster progress on our major roads.

Which come to think of it is an oxymoron, as how much money is it currently costing the UK economy, major companies and private car drivers in the multitude of daily lost hours spent dawdling or stopped in traffic queues? How much in wages alone is spent on them being stationary when they could be getting somewhere and being productive?

I've been watching 'Britain's Busiest Motorway' on ITV recently and that shows some of the behind the scenes work down by Highways England. They quite clearly state that the M25 handles twice the amount of traffic it was designed for. So do you make it wider to accommodate that, or faster to get the flow increased?

Mind you, don't get me started on the A27 stretch between Polegate and Lewes! They've been promising dual lanes for decades due to safety and traffic flow considerations and we still have the major route through East Sussex exactly as it was 40 or 50 years ago.

This week another driver died on that stretch of road, how many more have to die before they upgrade it?

[PorkInsider]

funkyrobot said:

Dan Trent said:

PorkInsider said:

I might be missing something here, but the particular section of the M1 being discussed in the article has some roadside signs - albeit quite small and poorly positioned ones - which read:

REDUCED SPEED LIMIT IN FORCE DURING TECHNOLOGY COMMISIONING

So presumably, even though they've finished the work to get to 4-lane running on that section, they're still fancying around with the CCTV or something?

Or am I missing something else?

Very interesting and your eyesight is clearly better than mine! If that's the case I'll happily eat (some of!) my words!

Dan

As others have mentioned Dan, can't you utilise some PH resources and look into this properly. I.e., get some time with someone from highways or even visit a control centre and get them to explain and show you the reasoning behind these lower limits?

I think it would be a good use of time to follow this up.

Would definitely be interesting.

I do get the feeling that the variable limits are used very liberally. It 'seems' to be the case that the limit is reduced at every opportunity. Completely understandable, and indeed essential, when there's a stranded vehicle or something similar, but I travel the Yorks/Nottts stretch of the M1 regularly at various hours and can't recall the last time there wasn't a reduced limit on at some point, even outside the roadworks sections.

[JeremyH5]

I just used M1 south from Meadowhall to A57 and there were no limits set on gantries. The time to use this bit of motorway is 9:38am

[mrnoisy78]

Mandown46 said:

Dan, I'm somewhat disappointed.

Last time this was raised, one of my fine colleagues took the time to explain in detail how these work, and made you an offer to get you into the control room, and would have probably been able to get you some time out with the on road patrols too.
He had done this before for groups of PH'ers.
I remember discussing it in private with you as well.

I can only assume you didn't take him up on this, only to see you repeating the rant again is frustrating.

I'll try to cover some of the points, please note I can't comment on the section you are highlighting as its not on my patch.

If the signals are clearly wrong, showing fog in clear sunlight for example. (Though i haven't had that happen in my area for several years) you can report them.

0300 123 5000

You can, but we're not supposed to use our phones while driving remember?
In all seriousness, my feeling is that half the problem is the way these systems are managed.
There should be better monitoring controls in place to prevent the system screwing up, and in the field of risk controls and tests for a motorway speed governing system should require more testing than evidently takes place against whatever software governs this stuff.
Or in a more concise statement - if it screws up it should automatically switch OFF not drop the speed limit and inconvenience hundreds / thousands.

Mandown46 said:

You can also use that number to report potholes or anything else wrong you see with the motorways or major roads run by Highways England (not Agency, that doesn't exist anymore)

The speed signals are designed to regulate traffic flow. at rush hours this will mean that the speeds displayed are changing as traffic volume changes, so whilst the system will attempt to keep traffic moving as quickly as possible, it will slow things down where bottlenecks or stop start traffic is forming, you will usually find this is at busy junctions or where other motorways merge or split off.

Despite popular opinion, this system does work. yes, its frustrating as hell to be sitting in traffic moving at 50mph when you, as a pro driver think you could be doing at least 70mph, but the stats show that more traffic is getting through the junctions at a faster speed than when people are left to their own devices.
What tend to happen then is your stop start traffic as drivers hammer it up to the car in front, then slam on their brakes and cause a ripple effect, usually involving an accident as some dope isn't paying attention.

The system is automated, monitored by sensors both in the ground, and recently radar at the side of the road. (the under tarmac loops involving a lot or roadworks to fix when they go wrong)

This system is better than it was a few years ago, and is continually being improved with new technology. Yes, as one of the (insert your preferred insult here) operators in the control room it is incredibly frustrating when you check CCTV to see why a speed has triggered, and its down to a abload, or some truck crawling up a hill, I don't know if they will ever solve that.

Personally when driving the M25 at night (2am) between the M4 and M3 junctions, I've seen speed limits of 40 and 50 when the road is dead and there's literally no traffic. That makes zero sense.
You also note - lots of roadworks to fix the sensors when they go wrong - which is sheer lunacy in itself - surely in this day and age we can come up with a better solution that doesn't require digging up the road when a sensor breaks. I know you don't control that, but to hear it is simply mind boggling.
I would prefer to see the money spent on resurfacing our country's worst pot holed roads - not filling pot holes on the cheap whilst the rest of the road breaks up, and not on costly gantry technology which doesn't work half the time, and when it does "work" frequently slows everything else down for no good reason (e.g. an accident that happened an hour ago).
I think you'll find that however you try and sell it, whether it's "traffic volume management" or "safety", a large majority will only accept a minor number of those arguments - basically it's not a popular solution to try and manage the roads because there is no human element to employ common sense in our nanny state age.
Cameras can't manage tailgaters, lane hoggers and so forth although I'm sure it's only a matter of time before someone higher up decides they'll give that a go too...

Mandown46 said:

With regards to losing the hard shoulder, I'm still 50/50 on it. Short of being able to build extra lanes, which would be nice, its the best solution available. No, I don't think there are enough emergency refuge areas. No, it hasn't been the utter death destruction and carnage everyone predicted. Generally, the vast majority of people who stopped on the hard shoulder were idiots who had no reason to stop there, and could quite happily have carried on to a junction or services.

As for speed limits by the back door, that's really something you would have to take up with people paid significantly more than me. What I do know is that the Traffic Officers, both on road, and in the control rooms work incredibly hard to keep people safe and moving, even if it doesn't always appear that way at the time.

Just to show I'm not all bad (!) I agree on the hard shoulder piece; the government and councils are allowing new housing estates everywhere and in the South they seem to be building them right next to motorways so it's going to be hard to build more lanes if they carry on.
I still maintain though that if the police had more budget for highway patrols then they could effectively sort out the lane hoggers who are frequently the cause of tailbacks because they can't apparently bear to move out of the middle or fast lane to let other users pass them when they're only doing 60mph (in NSL of course )
You see this all the time on the M25, people sat in the second or even third lane with nothing for half a mile in front of them yet making no effort to move out of the way.

Traffic officers do a difficult job especially given how police numbers and budgets have been cut - I'd prefer to see the money spent on them because a camera won't come to your aid in the event of an accident, or if you break down in an unsafe location, etc.

Promise that's my rant over!

[anonymous-user]

This is similar to IndyRef 2; ask the question and keep asking it until you get the answer you want.

The two threads I posted links to cover a lot of the discussion points being talked about in this thread. My point being that try as we might, those who work in highways maintenance have inputted to explain why things are like they are, and why an unrestricted Autobahn motoring nirvana isn't an option on the table.

We also tried to explain why motorway widening wasn't an option, why increased speed limits weren't an option, why traffic management being put on and taken off daily...wasn't an option. Some were receptive to the information, others seem to think we were talking tripe and they knew more about managing motorway networks than those tasked with doing so.

It's a pity articles like this pop up once or twice a year, when much of the content has been explained and the general consensus among those who took the facts on board, was that actually it's the most practicable system available given the constraints we work within.

[havoc]

tankplanker said:

f they were used sensibly then I would have more time for the variable speed limits, but the one leading up to the M40 junction on the M42 usually goes something like 60 - 50 - 50 - 60 - 40, with the queuing/heavy traffic sitting around the 40 mph gantry and the 60 gantry set just before a bend that those in the outside lane cannot see that the next gantry is 40. As everybody seemingly matches the speed of the car in front as that is easier than speedo watching, and anybody "dawdling" in the outside lane is undertaken (where possible) or aggressively tail gated, so the traffic moves at the exact posted limit plus about 10%.

I semi-regularly do that M42 stretch (not always at rush-hour), and:-
- I have only ONCE in the last 2-3 years seen the gantry signs off. It was so unusual I did a double-take. Most of the time there's a 60-limit, NO hard-shoulder running, and NO need for a reduced limit*.
- FREQUENTLY the posted limit yo-yo's between gantries, which is at best frustrating and at worst dangerous, and contributes to the discontent felt by most motorists subjected to it...to go back to Dan's comment about respect for authority.
- Everyone looks bored silly and a lot of drivers DO spend an inordinate amount of time looking at their speedo's not at the road in front of them, or welded to the bumper of the car in front regardless (regularly overtake MLMs who are 2 carlengths from the car in front at 48mph, then the car in front pulls in so they suddenly accelerate to >60mph and undertake you!).

This system DOES offer on-paper advantages...but only if it's managed and operated properly. If not, then you get what we've currently got...



(PS - M25 stretch from M40 round to ~A3 seems better-managed and I've more frequently seen that without the gantries lit-up)



* Mainly because when you get to the M40 there's a similar amount of traffic which instantly goes up to 80+mph without any trouble whatsoever.

[big_rob_sydney]

Mandown46 said:

Dan, I'm somewhat disappointed.

Last time this was raised, one of my fine colleagues took the time to explain in detail how these work, and made you an offer to get you into the control room, and would have probably been able to get you some time out with the on road patrols too.
He had done this before for groups of PH'ers.
I remember discussing it in private with you as well.

I can only assume you didn't take him up on this, only to see you repeating the rant again is frustrating.

I'll try to cover some of the points, please note I can't comment on the section you are highlighting as its not on my patch.

If the signals are clearly wrong, showing fog in clear sunlight for example. (Though i haven't had that happen in my area for several years) you can report them.

0300 123 5000

You can also use that number to report potholes or anything else wrong you see with the motorways or major roads run by Highways England (not Agency, that doesn't exist anymore)

The speed signals are designed to regulate traffic flow. at rush hours this will mean that the speeds displayed are changing as traffic volume changes, so whilst the system will attempt to keep traffic moving as quickly as possible, it will slow things down where bottlenecks or stop start traffic is forming, you will usually find this is at busy junctions or where other motorways merge or split off.

Despite popular opinion, this system does work. yes, its frustrating as hell to be sitting in traffic moving at 50mph when you, as a pro driver think you could be doing at least 70mph, but the stats show that more traffic is getting through the junctions at a faster speed than when people are left to their own devices.
What tend to happen then is your stop start traffic as drivers hammer it up to the car in front, then slam on their brakes and cause a ripple effect, usually involving an accident as some dope isn't paying attention.

The system is automated, monitored by sensors both in the ground, and recently radar at the side of the road. (the under tarmac loops involving a lot or roadworks to fix when they go wrong)

This system is better than it was a few years ago, and is continually being improved with new technology. Yes, as one of the (insert your preferred insult here) operators in the control room it is incredibly frustrating when you check CCTV to see why a speed has triggered, and its down to a abload, or some truck crawling up a hill, I don't know if they will ever solve that.

With regards to losing the hard shoulder, I'm still 50/50 on it. Short of being able to build extra lanes, which would be nice, its the best solution available. No, I don't think there are enough emergency refuge areas. No, it hasn't been the utter death destruction and carnage everyone predicted. Generally, the vast majority of people who stopped on the hard shoulder were idiots who had no reason to stop there, and could quite happily have carried on to a junction or services.

As for speed limits by the back door, that's really something you would have to take up with people paid significantly more than me. What I do know is that the Traffic Officers, both on road, and in the control rooms work incredibly hard to keep people safe and moving, even if it doesn't always appear that way at the time.

Mandown, one thing I just cant get my head around, is why the 50 limits apply for road workers, especially on Sundays, when most of the time, these guys arent even working?

What can be done about this???

[saaby93]

fuelracer496 said:

This is similar to IndyRef 2; ask the question and keep asking it until you get the answer you want.

The two threads I posted links to cover a lot of the discussion points being talked about in this thread. My point being that try as we might, those who work in highways maintenance have inputted to explain why things are like they are, and why an unrestricted Autobahn motoring nirvana isn't an option on the table.

We also tried to explain why motorway widening wasn't an option, why increased speed limits weren't an option, why traffic management being put on and taken off daily...wasn't an option. Some were receptive to the information, others seem to think we were talking tripe and they knew more about managing motorway networks than those tasked with doing so.

It's a pity articles like this pop up once or twice a year, when much of the content has been explained and the general consensus among those who took the facts on board, was that actually it's the most practicable system available given the constraints we work within.

I dont think that was the general consensus
I posted a page back that the consensus seems to be from these threads it's not working properly
It can work say at the M6 M5 junction when its busy
The M42 M40 junction doesnt seem to work with its haphazard limits that seem to cause more congestion than they resolve
- maybe the detectors see traffic slowing down for the junction thinks theres a hazard drops the limit for that gantry them traffics back up to speed foe the next
It's rubbish where theres nothing about and a randomly determined limit, perhaps based on a solitary truck going slowly past the sensors

[anonymous-user]

big_rob_sydney said:

Mandown, one thing I just cant get my head around, is why the 50 limits apply for road workers, especially on Sundays, when most of the time, these guys arent even working?

What can be done about this???

This was explained in the previous article / thread. Traffic management and reduced speed limits are put in place when works are being carried out, often with revised lane geometry (plan alignment, lane width reduced, lane number reduced). Reduced lane widths can only be run at a reduced speed limit (often 50mph on motorways). This is a legal requirement due to Chapter 8 and other relevant traffic regulations.

In times where work isn't being undertaken, or at least you cannot see work being undertaken - it's safer and more cost efficient to leave the TM in place. It takes time to put it out and road workers are most at risk during the operation due to the requirement for them to be adjacent to a live lane.