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PostPosted: Thu Jul 26, 2007 21:10 
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This idea/concept is not for the faint hearted. It requires a degree of numeracy in matters of probability, statistics and mean values to appreciate the subtleties of the invention. So please move on if you find these matters boring. But before you do please note that this device will substantially reduce traffic jams and frustrating delays on our roads.

The concept is the subject of a Patent Application [GB0411710.7]now lapsed due to cost and ill health which fully describes the invention and is available on the internet via the UK Patent Office. However here is a brief description:

The concept/invention in it‘s fully developed stage will enable a Traffic Authority to control in real time the Traffic Density at any section of a road network system where the invention has been implemented. This means that potential congestion can be recognised and action taken to iron out the peak loads to enable smooth traffic flows across the system. In it’s simpler forms it can be used to enable traffic to flow through road works without the need to queue or substantially decrease speed.
This is all done without recourse to black boxes in vehicles or GPS technology.

The system is based around the concept of the “Interactive Cats Eye” [ICE} which is in essence a rapid response [seconds] traffic light in the form of a road stud set preferably in the centre of the carriageway so that vehicle wheels pass on either side.
These units are set along the road network at say half mile intervals [or less] and are linked together, and to a central Controlling Processor.
Each unit counts the number of vehicles per minute passing and relays this to the Central Processor which then issues instructions to the unit to regulate the timed sequence of traffic lights incorporated into the unit, and so controls the behaviour of the traffic.
Hang on! - don’t go ape at this point! In normal mode the sequence is in the order of 2 to 3 seconds which relates to the usual time interval between vehicles so there is no question of these units forcing traffic to stop as with normal traffic lights. They are only triggered by the passage of a vehicle and otherwise are a default green.
In practice any driver would experience the following kind of scenario where normal traffic flow prevailed: -
On a clear motorway you would pass over a green light every half mile or so. As you approached a car ahead you would note that as it went over an ICE unit the light turned to red, then amber and finally to green; at which later point you would drive over it. However as you came up closer to the lead car you would reach a point when the light would be at amber when you passed over it, and you would then be near the point when you were too close behind the car ahead for safety. If you wound up going over the light when it was showing red then you would definitely be “Tailgating”.
In this scenario the ICE units are merely acting as speed sensitive Chevrons to remind drivers to keep their distance.
However, the clever bit comes when the Central Processor detects potential congestion downstream. Here you would find that the red light would start staying on for a longer period [say 2.5 seconds instead of 2, so you would forced back from the car ahead. And so would all the other cars. In effect the system is reducing the Traffic Density so that when you arrive at the potential congested area it will not be there! This will happen because the computer has added together the number of cars approaching the junction or road works where the congestion was likely to occur and has made sure that the road capacity is not overwhelmed by reducing the rate of arrival of traffic from upstream.
This is an huge oversimplification but will do for now. I could go on and it raises many issues; but would suggest that if you are interested in further details please ask. Otherwise I invite comments. At least it is a better idea than road charges and probably far more effective.





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PostPosted: Thu Jul 26, 2007 21:47 
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... so you would forced back from the car ahead...

Could you outline what "forces" you back from the car ahead?

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PostPosted: Thu Jul 26, 2007 21:55 
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malcolmw wrote:
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... so you would forced back from the car ahead...

Could you outline what "forces" you back from the car ahead?

Nothing I hope!
Perhaps informed 'persuasion' would be a better way forward, some little lights alone won't do it.

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PostPosted: Thu Jul 26, 2007 23:38 
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you'd be doing well to see a cat's eye on a sunny day!

Hmmm. Then again, a few more summers like this and maybe it won't be such a problem!


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PostPosted: Fri Jul 27, 2007 00:20 
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If I understand this right then...
You drive along past these cats eyes. If they are green you're probably ok. If they are amber or red then you probably want to slow down a tad in order to optimise the traffic flow?

Assuming the system works (M42 :roll:) and is being run for the right reasons this sounds like a good idea but I don't know how practical it would be in reality, especially as so many "safety" or "congestion" related devices and schemes exist which do the exact opposite of what we are told they will do.

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PostPosted: Fri Jul 27, 2007 04:40 
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This would work in theory - it is the same basic premis on which the London Underground trains work. The trouble is that people would start to rely on lights instead of their own intelligent observations and an increase of rear end shunts would be the inevitable result. I think.


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PostPosted: Fri Jul 27, 2007 10:02 
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It's an interesting idea, certainly.

There may be issues surrounding the difference between density and throughput that would make it fail in principle (let alone in practice). I'm still trying to think that bit through.

But increasing traffic density does increase throughput...

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 Post subject: How to reduce congestion
PostPosted: Fri Jul 27, 2007 10:45 
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Some good responses
1) Malcolmw - "What forces you back?" - Mainly Intelligence. All the ICE is doing is informing you that if you drive in the red sector then you will very likely have to slow down or stop at some point downstream. If, however you stay in the green sector then the likelhood will be much much less. For who are "thick" - no doubt the Traffic Authority will invent some way of snapping them on camera. Oh dear - not another lump hardware. Heaven forebid.
However the system is based on probability and density, not on the actions of the odd driver or two. It would however depend on the general acceptance of the motorist for it's success.

2) Smeggy - I think the above fits here.

3) Mole - A question of good practical design. Perhaps we should leave this aspect to the engineers. ie What about snow etc?

4) Ziltro - You have it right. By backing off into the green sector and mainaining speed as per the ICE lights you will be far less likely to have to slow or stop later. It is important to note here that once a queue is forced to stop then it will cost every vehicle approx. 15 seconds of time at least. If you happen to be the 100th. car then that is 25 minutes of drumming on the steering wheel.

5) - Roger - Don't agree here. The units will be spaced well apart and only provide ancillary information. In fact there is a facility in the invention to provide a link to your cruise control if you have one. Boring - Boring Boring?ZZZZ! Ooops - Perhaps not a good idea.

Finally here is a further snippit of info for consideration:
A lane or carriageway has its capacity fixed by safety considerations. This is currently about 30 vehicles per minute ie.: a TBV of 2 seconds between vehicles
If road works block a lane on the motorway then the capacity of the two lanes is 60 VPM [Vehicles per Minute] so what is the point of allowing 90 VPM [ 3 lanes X 30 VPM] to arrive at the start of the road works?
Best have 3 lanes at 20 VPM or a TBV of 3 seconds. Ie: Set the ICE red light to 3 secs.
This is a bit of a simplification as there is a lane merge requirement; but that is another story.

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PostPosted: Fri Jul 27, 2007 11:53 
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ICEAFE wrote:
Finally here is a further snippit of info for consideration:
A lane or carriageway has its capacity fixed by safety considerations. This is currently about 30 vehicles per minute ie.: a TBV of 2 seconds between vehicles
If road works block a lane on the motorway then the capacity of the two lanes is 60 VPM [Vehicles per Minute] so what is the point of allowing 90 VPM [ 3 lanes X 30 VPM] to arrive at the start of the road works?
Best have 3 lanes at 20 VPM or a TBV of 3 seconds. Ie: Set the ICE red light to 3 secs.


Doesn't this reveal a fallacy?

If it works as intended we're restricting the capacity of a much larger road section.

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PostPosted: Fri Jul 27, 2007 12:24 
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Quote:
If it works as intended we're restricting the capacity of a much larger road section.


That's true, but the point of the ICE is to delay/eliminate the onset of flow breakdown. Once the flow stops vehicles arrive faster at the back of the queue than they can leave at the front and the jam builds up. As long as the traffic is still flowing the total capacity is higher than after the breakdown.


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PostPosted: Fri Jul 27, 2007 17:12 
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Yes - Semitone is right. The mathematics is a bit complex and is down to Mr. Poisson that renowned mathematician with his queing theory which relates the probability of a queue forming against a function of the ratio between the arrival and the departure rates I won't go into details here but if you graph probable traffic speeds against TBVs [Time between vehicles]you get interesting results namely: At a mean TBV of 2.05 seconds there is a 50% probability that the traffic speed will be 65 mph. However if the mean TBV drops to 2 seconds then there is a 50% probability that the traffic will have to stop. Don't blame me blame Mr. Poisson.
But forget the maths just think on this - If you're doing 60 mph you will cover a mile in one minute. OK what if you have to stop? just work it out for time to decelerate, time to get into proper gear, time to accerate at probably less than 6 ft per sec squared until you get up to 60 mph again. How long to cover the mile now?
As Semitone says once the traffic stops the ratio of arrival to departure time shoots through the roof. - and all for failing to back off by a lousey 0.05 of a second!

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PostPosted: Fri Jul 27, 2007 17:45 
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ICEAFE wrote:
The system is based around the concept of the “Interactive Cats Eye” [ICE} which is in essence a rapid response [seconds] traffic light in the form of a road stud set preferably in the centre of the carriageway[...]
And motorbikes?

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PostPosted: Sat Jul 28, 2007 10:09 
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Yes Bottyburp - We must not exclude our lethal colleagues must we? In spite of our envy.

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PostPosted: Mon Jul 30, 2007 18:45 
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ICEAFE wrote:
Yes Bottyburp - We must not exclude our lethal colleagues must we? In spite of our envy.
Eh?

I was referring to
ICEAFE wrote:
The system is based around the concept of the “Interactive Cats Eye” [ICE} which is in essence a rapid response [seconds] traffic light in the form of a road stud set preferably in the centre of the carriageway

As in, I'd rather not have studs on my riding line, especially in the wet!

And who are "our lethal colleagues" you refer to?

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PostPosted: Mon Jul 30, 2007 20:48 
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Bottyburp has made a very valid observation here. These studs should not cause problems with motor cycles. Any suggestions anyone?
I back off Bottyburp!!!. I am only trying to keep this all lighthearted. I sold my 500 cc side vv Norton in about 1952 when I concluded that the combination of my arrogance and the weird roadholding characteristics were lethal. I suppose I have held this predudice for years oblivious of the advances in technology. But you must admit some of your colleages do wizz past at mind boggling speeds on occasions!? No - I am still envious.
However we are losing the plot. Why has no-one yet challenged the obvious problem of the weavers? If we all back off as I am suggesting in accordance with the ICE lights then WOW! all that space for the weavers. Any suggestions for how we tackle that problem?

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PostPosted: Mon Jul 30, 2007 21:15 
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ICEAFE wrote:
Bottyburp has made a very valid observation here. These studs should not cause problems with motor cycles. Any suggestions anyone?
I back off Bottyburp!!!. I am only trying to keep this all lighthearted. I sold my 500 cc side vv Norton in about 1952 when I concluded that the combination of my arrogance and the weird roadholding characteristics were lethal. I suppose I have held this predudice for years oblivious of the advances in technology. But you must admit some of your colleages do wizz past at mind boggling speeds on occasions!? No - I am still envious.
However we are losing the plot. Why has no-one yet challenged the obvious problem of the weavers? If we all back off as I am suggesting in accordance with the ICE lights then WOW! all that space for the weavers. Any suggestions for how we tackle that problem?


Any significant weaving will likly trigger flow breakdown and cause a jam!. "Darwin" might have a role to play, from the benign level of "Weavers" simply being regarded as social outcasts to the more extreme version where a "weaver" who triggers a jam is dragged from his vehicle by an angry mob and trampled into a greasy smear! :twisted:

(Like Saudi! you dont have to cut tooo many hands off before the shits get the message! :wink: )

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PostPosted: Tue Jul 31, 2007 13:56 
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ICEAFE wrote:
But you must admit some of your colleages do wizz past at mind boggling speeds on occasions!?
Do they? Can't say I'd noticed many pass me when I'm on my Blackbird... :hehe:

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PostPosted: Tue Jul 31, 2007 18:21 
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In theory I like the cheverons. Every one shoild have a good minimum distance from the car in front.

In practace I find them a nightmare. they cause congestion as drivers re-adjust they drive un-naturally. They recently put some on the M4 near Bristol and caused a problem that did not exist.

My fear is that a riple effect could be made worse rather than better down the motorway as drivers adjust.
driver 1 gets blinded by the sun as he rounds a corner and lifts off the gas, driver 2 gets a red cats eye and over adusts his spacing causing driver 3 and 4 to do the same and driver 5,6,7 have a pile-up for what should have been a simple lift off the gas.

You could do the same with onboard camera and spacial awareness software. mapping objects and thier speed infront. But I still feasr the ripple effect. If you were all traveling at 2 seconds apart and a sudden rain storm happened and they all switched to 4 second gap you would instantly need to apply maximum breaking. by car 5 or 6 there would be no road.

If that happens on the motorway to a human , people drive for a few seconds off the gas at half the desired gap and ramp up thier mental resources to 150% and let it unravel.

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PostPosted: Tue Jul 31, 2007 19:42 
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The main problem with Chevrons is that they are not speed sensitive. A 2 sec gap at 70 mph is, to say the least, slightly different to one at 20 mph. I suspect they are set for an average speed of 60 mph. Also they are infrequent on motorways and only cover short distances thank goodness as they give me brain damage after a bit As a result they do create perturbations in the traffic flow in heavy conditions; but I find that once the traffic has settled down the average speed tends to be higher. Anyone agree?
The ICE units are speed sensitive and the software driving them would ensure that no sudden change in TBV would occur. These units would be working on probabilities and mean values not on sudden rain storms or myopic drivers. The whole point is to prevent the build up of traffic reaching critical levels where the laws of queuing activate to ensure sudden decreases in speed or finally congestion. Simple really.
We have all experienced the phantom traffic jam [no apparent cause]. And we have all experienced the sudden decrease in speed in the fast lane. [ again for no apparent cause.] It is basic mathematics.

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PostPosted: Tue Jul 31, 2007 19:58 
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anton wrote:
But I still feasr the ripple effect. If you were all traveling at 2 seconds apart and a sudden rain storm happened and they all switched to 4 second gap you would instantly need to apply maximum breaking. by car 5 or 6 there would be no road.

Not necessarily so.
Drivers also slow down, especially when they’re trying to maintain a larger gap.

To preserve the flow rate (of that from 70mph in good conditions) whilst maintaining an equally ‘safe distance’ based on half the available traction (which I guess is where the ‘2 to 4 second’ idea came from), the overall speed will have to halve.

In reality what happens is the less aware drivers usually over brake then overcompensate by under accelerating when scared awake, so amplifying the compression and expansion wave.

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