The future of smart motorways

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Chris5156
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Re: The future of smart motorways

Post by Chris5156 »

I suspect a database system would prove cheaper to implement than powered hardware transponders being procured and strapped to every sign. It would be more resilient, data storage and bandwidth are cheap and easily outsourced, and the cost and volume of network traffic over the mobile phone network is the problem of the phone companies and individual subscribers rather than the council so doesn’t have to be factored in. If I were in local government I wouldn’t be worrying about having to set up an online database open to millions of queries a day, but I would be worried about the idea of installing thousands of new bits of powered equipment. I can’t see how the cost of the latter could ever be justified.

Not, of course, that we are living in a world where either is a realistic prospect right now.
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Re: The future of smart motorways

Post by KeithW »

Chris5156 wrote: Sat Nov 27, 2021 07:37 I suspect a database system would prove cheaper to implement than powered hardware transponders being procured and strapped to every sign. It would be more resilient, data storage and bandwidth are cheap and easily outsourced, and the cost and volume of network traffic over the mobile phone network is the problem of the phone companies and individual subscribers rather than the council so doesn’t have to be factored in. If I were in local government I wouldn’t be worrying about having to set up an online database open to millions of queries a day, but I would be worried about the idea of installing thousands of new bits of powered equipment. I can’t see how the cost of the latter could ever be justified.

Not, of course, that we are living in a world where either is a realistic prospect right now.
Or we could of course just read the signs that are already there which is what I advocate !

Many cars can already do that and display the speed limit on the display, which mine does. Now they are fallible, I have seen mine pick up the signs on the back of a truck so automatically setting the limiter seems like a bad idea but it could easily sound a warning chime which at least one Satnav I had would do. If I jump into the car and head out of town I will see darn few signs that read 30 as its a built up area for the first 3 miles. As I recall the dashboard display sets a default of 30 at the start.

Personally I go for the 'it aint broke so dont fix it' approach but then I last got a speeding ticket in 1974 when I was young and daft. The other factor is that there are (rare) times when breaking the speed limit is morally if not legally justifiable. A medical emergency is one, if it was a relative or friend and time was of the essence I am afraid it would be pedal to the metal.
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Re: The future of smart motorways

Post by jnty »

KeithW wrote: Fri Nov 26, 2021 13:21
jnty wrote: Fri Nov 26, 2021 12:41

Yeah I was pretty sure it can't only have been Edinburgh that's done this. A really interesting look behind the scenes, thanks for that. Sounds like they've done speed limits etc. as well as just parking?
Let me try and explain again the technical issues here. If you want to use speed limiting systems in cars that refer to TRO's then you are going to need some major infrastructure expenditure.

Lets assume you have a typical D2 road - you can easily have 40,000 vehicle movements per day and each vehicle will be making multiple queries as it travels. Even at 30 mph you will be covering over 13 metres every second, realistically means thousands of queries every minute and responses have to be in real time. Each Query/Response has to be individually addressed, this all has to happen in all weathers and in urban areas which in terms of RF propagation are problematic at best. This is going require a LOT of spectrum bandwidth, considerable computer power that is certified for real time operation and is highly resilient. We are talking massive data centres consuming large amounts of power and then you have to add additional discrimination systems to determine if you are on the motorway or the parallel local access road. Take a look at NATS (National Air Traffic Control System) to see the sort of thing you need for a MUCH lower number of movements.

Alternatively you can use the KISS principle (Keep it Simple Stupid) and simply have radio emitters to back up the visual signs by narrowcasting the speed limit. No massive databases, datacenters or huge overheads just a simple transponder. Simpler yet you rely on signs, the human eyeball Mk 1 and speed cameras - Oh wait we already do this.
These databases already exist, managed by private companies eg. TomTom and used by the thousands of cars that already have database-backed ISA built in. Even Google Maps will have a stab at it these days. There's no need to query the databases in realtime - they can be downloaded to the car in their entirety and be kept up to date with regular incremental updates - so there's no real technical limitations here, and there's certainly no need to put transponders everywhere.
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Re: The future of smart motorways

Post by XC70 »

KeithW wrote: Sat Nov 27, 2021 11:09The other factor is that there are (rare) times when breaking the speed limit is morally if not legally justifiable. A medical emergency is one, if it was a relative or friend and time was of the essence I am afraid it would be pedal to the metal.
I am pretty sure that in the case of a medical emergency that there is a valid legal defence to breaking the speed limit.
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Re: The future of smart motorways

Post by Ruperts Trooper »

XC70 wrote: Tue Nov 30, 2021 12:24
KeithW wrote: Sat Nov 27, 2021 11:09The other factor is that there are (rare) times when breaking the speed limit is morally if not legally justifiable. A medical emergency is one, if it was a relative or friend and time was of the essence I am afraid it would be pedal to the metal.
I am pretty sure that in the case of a medical emergency that there is a valid legal defence to breaking the speed limit.
That sounds like an urban myth
https://www.legislation.gov.uk/ukpga/1984/27/section/87
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Re: The future of smart motorways

Post by Bryn666 »

XC70 wrote: Tue Nov 30, 2021 12:24
KeithW wrote: Sat Nov 27, 2021 11:09The other factor is that there are (rare) times when breaking the speed limit is morally if not legally justifiable. A medical emergency is one, if it was a relative or friend and time was of the essence I am afraid it would be pedal to the metal.
I am pretty sure that in the case of a medical emergency that there is a valid legal defence to breaking the speed limit.
No, it's mitigation that may result in a lesser penalty, not a valid defence in itself. You'd also have to prove it with medical evidence that the person was in need of immediate assistance and also that a 999 call was not viable at the time because speeding is strict liability and it's down to you to prove you weren't breaking the law.
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Re: The future of smart motorways

Post by ais523 »

Ruperts Trooper wrote: Tue Nov 30, 2021 12:50
XC70 wrote: Tue Nov 30, 2021 12:24 I am pretty sure that in the case of a medical emergency that there is a valid legal defence to breaking the speed limit.
That sounds like an urban myth
https://www.legislation.gov.uk/ukpga/1984/27/section/87
The relevant law says "being used for ambulance purposes", which is unclear to me – presumably that's something the lawyers would have to fight over in court!

(There's also an explicit allowance that you can break the speed limit if an NHS ambulance service requests that you do so to respond to an emergency; presumably that might be a helpful exception to use if the person calling 999 is in a better position to take someone to hospital than the ambulance service themselves are.)
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Re: The future of smart motorways

Post by Herned »

Back to the subject of the topic, I was driving north on the M5 today. Heading onto the smart section north of Worcester, the gantry signs started indicating a lane closure ahead, and the speed limit was stepped down to 40mph, alongside the 40mph limit the VMS stated "stranded vehicle ahead". The following two VMS were completely blank, giving the impression that the hazard had been cleared... then just past the northbound slip from J5, there was the stranded vehicle, luckily with a breakdown truck in attendance with all it's lights flashing. Had that not been there, the car would have been pretty tricky to spot as there was light rain and spray and it was ~4pm so semi-dark.

How can the system work in this way, with the nearest VMS to the incident being blank? This seems unbelievably dangerous to me, and I have told HE my thoughts about it as well
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Re: The future of smart motorways

Post by Bendo »

Because the equipment is absolutely rubbish and evidently doesn't work all of the time. On the other hand, a blank gantry doesn't have any meaning despite many taking it to mean restrictions have ended and NSL applies again.
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Re: The future of smart motorways

Post by Bomag »

Bendo wrote: Sat Dec 11, 2021 22:37 Because the equipment is absolutely rubbish and evidently doesn't work all of the time. On the other hand, a blank gantry doesn't have any meaning despite many taking it to mean restrictions have ended and NSL applies again.
Due to the way the tech group in Bristol got to fiddle with the draft TSRGD a red x does apply until cancelled; however, each AMI/MS4 is a terminal and given the spacing of signals a blank aspect would mean NSL applies.
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Re: The future of smart motorways

Post by Bendo »

That's not how I interpreted this https://www.legislation.gov.uk/uksi/201 ... ion/3/made
(2) A section of road is subject to a variable speed limit in relation to a vehicle being driven on it if—

(a)the road is specified in the Schedule;

(b)the vehicle has passed a speed limit sign; and

(c)the vehicle has not passed—

(i)another speed limit sign indicating a different speed limit; or

(ii)a traffic sign which indicates that the national speed limit is in force.


Nothing like perfectly clear legislation. But the repeaters (or lack of) is a good point I'll conceed.
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Re: The future of smart motorways

Post by JammyDodge »

Bendo wrote: Sun Dec 12, 2021 00:10 That's not how I interpreted this https://www.legislation.gov.uk/uksi/201 ... ion/3/made
(2) A section of road is subject to a variable speed limit in relation to a vehicle being driven on it if—

(a)the road is specified in the Schedule;

(b)the vehicle has passed a speed limit sign; and

(c)the vehicle has not passed—

(i)another speed limit sign indicating a different speed limit; or

(ii)a traffic sign which indicates that the national speed limit is in force.


Nothing like perfectly clear legislation. But the repeaters (or lack of) is a good point I'll conceed.
This part is very interesting
(4) For the purpose of this regulation a speed limit sign is to be taken as not indicating any speed limit if, ten seconds before the vehicle passed it, the sign had indicated no speed limit or that the national speed limit was in force.
I know this is wrong (would be very interesting as a defence in court):
But it does seem like it states there is no speed limit enforced if the sign is blank, only when a sign is displayed. The use of "or" is the interesting part, as that could theoretically be used to imply that there is no speed limit, unless the national speed limit sign (or any other) is displayed
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Re: The future of smart motorways

Post by jnty »

JammyDodge wrote: Sun Dec 12, 2021 04:48
Bendo wrote: Sun Dec 12, 2021 00:10 That's not how I interpreted this https://www.legislation.gov.uk/uksi/201 ... ion/3/made
(2) A section of road is subject to a variable speed limit in relation to a vehicle being driven on it if—

(a)the road is specified in the Schedule;

(b)the vehicle has passed a speed limit sign; and

(c)the vehicle has not passed—

(i)another speed limit sign indicating a different speed limit; or

(ii)a traffic sign which indicates that the national speed limit is in force.


Nothing like perfectly clear legislation. But the repeaters (or lack of) is a good point I'll conceed.
This part is very interesting
(4) For the purpose of this regulation a speed limit sign is to be taken as not indicating any speed limit if, ten seconds before the vehicle passed it, the sign had indicated no speed limit or that the national speed limit was in force.
I know this is wrong (would be very interesting as a defence in court):
But it does seem like it states there is no speed limit enforced if the sign is blank, only when a sign is displayed. The use of "or" is the interesting part, as that could theoretically be used to imply that there is no speed limit, unless the national speed limit sign (or any other) is displayed
That part is only clarifying the meaning of the speed indicated by a sign for the purposes of the first part:
(1) No person shall drive a vehicle on a section of a road which is subject to a variable speed limit at a speed exceeding that indicated by a speed limit sign.


So the regulation as a whole is specifically drafted so it can only add restrictions rather than overriding existing ones. "Indicating no speed limit" just means that no extra restrictions apply due to (1), not that the sign is explicitly indicating that no speed limit at all applies, and even if it did it would be irrelevant as there is no provision which gives it legal force.

It's a bit Simon Says - the regulation could go on to mention the possibility that a sign might say "no elephants beyond this point" but, without a further stipulation that the meaning of this sign is to prohibit elephants from continuing, it's meaningless.
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Re: The future of smart motorways

Post by Micro The Maniac »

On my Smart Motorway Speed Awareness Course, it was stated categorically by the instructors that a blank sign means National Speed Limit and all other restrictions are ended.
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Re: The future of smart motorways

Post by Bendo »

I wouldn't put any value on anything that is spouted on any awareness course. They are often done by people with zero clue, so many horror stories.

Anyhow, now speed limits are generally show on MS4 signs on modern and updated schemes, not all MS4 signs are for the purposes of showing the limit, so how do you know if a particular blank MS4 is for general info or for "smart" motorway operation?
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Re: The future of smart motorways

Post by Conekicker »

Micro The Maniac wrote: Mon Dec 13, 2021 13:10 On my Smart Motorway Speed Awareness Course, it was stated categorically by the instructors that a blank sign means National Speed Limit and all other restrictions are ended.
That's generally correct, with the rider that the sign could be faulty and not displaying a message at all.
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Re: The future of smart motorways

Post by Micro The Maniac »

Conekicker wrote: Tue Dec 14, 2021 10:48
Micro The Maniac wrote: Mon Dec 13, 2021 13:10 On my Smart Motorway Speed Awareness Course, it was stated categorically by the instructors that a blank sign means National Speed Limit and all other restrictions are ended.
That's generally correct, with the rider that the sign could be faulty and not displaying a message at all.
Given that any letter in the post includes a photo of the MS4, is a blank MS4 likely to be sufficient evidence for a NIP :confused:
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Re: The future of smart motorways

Post by TS »

I don't know if it has been noted before on this thread, but the signs on the approach to the M27 smart motorway works have had the "smart" removed.s

They now appear to say "Upgrading to motorway" which is obviously silly, so I wonder whether it is delinquency or official. If it is some wag who has gone along and removed the lettering, they've done so at both the Rownhams and the Cosham end, which would be quite an effort even to make a strongly-held point!

The sign at Rownhams is here:
"Upgrading to smart motorway" (May 2021)
"Upgrading to ..... motorway" (November 2021)
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Re: The future of smart motorways

Post by jnty »

TS wrote: Tue Dec 14, 2021 14:53 I don't know if it has been noted before on this thread, but the signs on the approach to the M27 smart motorway works have had the "smart" removed.s

They now appear to say "Upgrading to motorway" which is obviously silly, so I wonder whether it is delinquency or official. If it is some wag who has gone along and removed the lettering, they've done so at both the Rownhams and the Cosham end, which would be quite an effort even to make a strongly-held point!

The sign at Rownhams is here:
"Upgrading to smart motorway" (May 2021)
"Upgrading to ..... motorway" (November 2021)
"Take away the smart bit so it says 'Upgrading motorways!'"
"OK, take away 'smart', got it boss."
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Re: The future of smart motorways

Post by brummie_rob »

Same happened on the M6 J13-J15 except it says 'Upgrade to motorway'
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