Road Safety News
 

New transport secretary less enthusiastic about motorway limit increase

Wednesday 3rd October 2012

The Government has not ruled out increasing the motorway speed limit from 70 to 80mph, though the new transport secretary appears less attracted to the idea than his predecessor, according to Fleet News.

The idea was first mooted by the former transport secretary Philip Hammond, who claimed the increase would be good for business.

However his replacement, Patrick McLoughlin, appears less convinced. According to Fleet News, he said it is important that “we never lose sight about the issue of safety on our roads” and that safety was “paramount” to his thinking.

Meanwhile, a DfT spokesman said it was currently working on an impact assessment of an 80mph speed limit on sections of the motorway network with variable speed limits and considering the criteria for where and under what conditions the 80mph speed limit might be applied.

“We aim to consult on this later in the year alongside the broader work on a roads strategy,” he said.

Malcolm Heymer, traffic management adviser for the Association of British Drivers (ABD), said: “A 70mph limit was introduced in 1965, when the top speed of an average car was about 85mph and few could cruise at speeds much above 70.

“Today, an average car can cruise easily at 80mph or more. Consequently speeds have increased with about half of car drivers exceeding current limits.

“There’s decades of evidence that this is the best way to set speed limits to achieve maximum compliance, smoother traffic flow, fewer conflicts between vehicles and hence fewer accidents.

“According to DfT figures, the current 85th percentile speed on Britain’s motorways is 79mph, so an 80mph speed limit would match that.”

But Julie Townsend, deputy chief executive of the road safety charity Brake, believes that an 80mph limit would cause more people to be killed and seriously injured on motorways.

She said: “We welcome Mr McLoughlin’s comments that his priority is the safety of road users and his acknowledgement that managing traffic speed is crucial in preventing needless deaths and injuries.

“We look forward to hearing more from the new transport ministers on how they will usher in a better era for safety on roads and help to counter the recent increase in casualties.”

Click here to read the full Fleet News report.

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Quite right Reheman. Our mental state determines our behaviour on the road. I remember reading many years ago research where it was found that people who drove in a anti-social, arrogant, irresponsible (even criminal) manner were predisposed to behave this way just about everywhere anyway - not just on the road. Perhaps people should have to be psychologically tested as part of qualifying for a driving license as they would have to be in some other highly responsible positions requiring mental stability.
Hugh Jones, Cheshire

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+2

There are many pros and cons on this subject but my thoughts and experience is that the driver MUST have the correct instruction from day one of learning how to DRIVE (control) their vehicle which is not done by the instructors. Another point is the mental state of the driver.

I instructed my two on what they should and shouldn't do and when a mistake was made I shouted out what they had done wrong. They told me to inform them in a more gentle way but I then told them that if I shouted out they would remember not to do it again. Both passed first time and have travelled many thousands of miles without incident. Personally I drive at a speed which returns the better fuel consumption as I am on fixed income. I have no problem with higher speeds if they are not EXCESSIVE or dangerous, after all, we still have 1.5 million uninsured vehicles on the roads to contend with and I wonder which are considered the more dangerous. Speed or uninsured?
REMEMAN Derbyshire

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0

Eric: Have you misunderstood me? I was obviously talking about the individual driver slowing down when necessary as part of the whole ethos of driving defensively, not everyone en masse for the sake of it! Isn't that what you meant?
Hugh Jones, Cheshire

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+1

Hugh now accepts that %ile speed cannot, of itself, allow calculation of speed distribution. Instead he now claims that distribution is so consistent that experienced observers are able to estimate - not calculate - it accurately from the %ile figure.

If he means that he can do that regardless of road, weather, volume and how appropriate the speed limit is for those conditions I find that difficult to believe, because distribution MUST depend to a significant degree on these other factors, albeit there may be a "norm" for normal conditions.

Two examples - a motorway nearly at capacity at 70mph allows a much narrower choice of speed than a nearly empty one, and safe conditions result in more drivers near the speed limit than dangerous conditions, which inhibit some more than others.

So Hugh, which is it - do you take these other factors into account, or not?
Idris Francis Petersfield

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-5

Hugh
What I actually said was "A general reduction in speed is not guaranteed to improve safety or reduce the likelhood of emergencies". I stick by that.

Your thinking and rationale remains centred on the belief that slower is [automaticallly] safer.

I agree that defensive driving makes our roads safer but I fundamentally disagree with your statement "and that has to mean going slow enough to be able to stop". Being able to stop is dependent on having sufficient distance to do so in space you can see to be clear and being alert enough to apply the brakes when necessary.

That would be true at any speed. Driving too close or not concentrating at 20mph could more dangerous than a Class 1 Police Driver on the M1 at 120mph.

Good driving is so much more than "going slower", which is the impression you continue to give.
Eric Bridgstock, Independent Road Safety Research, St Albans

Agree (5) | Disagree (9)
-4

I presumed that Eric’s phrase about reduction in speed not improving safety was referring to the individual driver and not traffic as a whole - sorry if I misunderstood, however I am sure you would both agree that the key to reducing accidents is defensive driving by everyone and that has to mean going slow enough to be able to stop.

The 85th%ile speed is not inevitably dangerous, however for any given road, the safety margin is reduced at this speed for the characteristics of the road – hopefully that is why most motorists don’t actually do it.

Only about 4-5% actually drive at the 85th%ile speed – the remaining 80% (ish) drive slower - some inevitably a lot slower – and these lower speeds make up the 85th percentile speed in the first place which is why, once you’ve analysed a few, it serves as a reliable indicator of how many are doing what speed.
Hugh Jones, Cheshire

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0

Eric,
I am afraid I do not have the time to fully discuss this issue on paper. Sat in a car is really where it all happens and where all advanced driving scenarions can be experienced. I wish you well.
Alan Hale - South Gloucestershire Council Road Safety Team

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+1

Hugh, (about your response Eric) if there is a limit of 30 on a non-residential dual carriageway (not uncommon these days), do you seriously believe that reducing the limit to 20 would improve safety, by any amount, let alone anything measurable? What about increased non compliance with the limit and the negative effects that would bring? A general reduction of speed does indeed not guarantee improved safety.
Ian Belchamber, Poole

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-6

Hugh
There is nothing inherently dangerous about the 85%ile - it merely reflects what most people do, and do safely. It is determined by the natural behaviour of the driving population. No one sets out to reach the 85%ile speed or to change it.

Regarding your comment about slowing down working for you, I wonder if you are one of those hat-wearing Volvo drivers that get in everyone's way?
Eric Bridgstock, Independent Road Safety Research, St Albans

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-6

Hugh, how is it that your statement that percentiles ONLY indicate spread (which I now hope you realise is completely incorrect) is not misinformation, and suggesting that the 85%ile is a safe speed to drive, is? Should you review your thoughts about it, now, hopefully, that you understand percentiles and spreads a bit better? Seems to make lots of sense to me, a limit which is naturally largely self enforcing, bringing normal safe drivers out of conflict with the law so they can focus on observation not their speedo or looking for speed cameras, reducing journey times, congestion, traffic density, (and hence further accident opportunities), improving productivity, reducing the failed obsession with speed as the single most important factor, reintroducing more balanced attention to all forms of bad/dangerous driving, etc etc. These things are the reality.
Ian Belchamber, Poole

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-4

Eric’s earlier quote “better/safer/defensive driving can reduce the likelihood of emergencies, and is therefore worthwhile” is clearly right, but he then went on to spoil it by saying, more recently: “A general reduction in speed is not guaranteed to improve safety or reduce the likelihood of emergencies”.

Well it works for me and just about everyone else on the road.
Hugh Jones, Cheshire

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-2

Ian: My reason for commenting on this subject in the first place was simply to correct the mis-information regularly put out by some when mentioning the 85th%ile in the context of vehicle speeds (the low-risk, safe-speed nonsense) which if interpreted literally could lead to someone coming to grief on the road. You can delve into the finer points of maths and statistics if you like, but it does not change the reality of the situation.
Hugh Jones, Cheshire

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-1

Alan
Thanks for your reply but it suggests your thinking/training is limited.
"perhaps reducing their speed".

Emergencies can take various forms and response to them will obviously vary.

I suggest that emergencies can be mitigated by changing course and/or speed, and it will sometimes be safer to increase speed, while other times braking is appropriate. A general reduction in speed is not guaranteed to improve safety or reduce the likelhood of emergencies.
Eric Bridgstock, Independent Road Safety Research, St Albans

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-5

Eric,
If people receive advanced driving instruction they will be equipped far better to ensure that their style of driving is such that they have a driving plan, they do anticipate, they do observe, they do concentrate and they do ensure safety margins or if those margins are reduced then they need to take action in other ways by perhaps reducing their speed.

If they have had that training then they are better equipped to deal with the emergency in a safe way. What that safe way is is obviously dependent on the circumstances they are presented with and their level of concentration.
Alan Hale - South Gloucestershire Council Road Safety Team

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+2

Hugh, I’m not really sure what I can add. A percentile (whatever the number is) indicates where a value sits within a distribution but tells us nothing about the distribution (or spread), “academically” or otherwise, this is just the way it is, there really isn’t a debate.

Saying that the percentile tells us about the spread is like saying the air temperature determines the likelihood of rain, it just doesn’t. Of course, a professional using past experience, other methods and data could use air temp as one of many parameters to build an overall rain probability but that result simply can’t come from air temp alone.

You can use a SET of percentiles (quartiles) to determine a spread but a single %ile, 85 or otherwise, tells us nothing about the spread. It is also simplistic to say that different road types with similar percentiles will have similar spreads.
Ian Belchamber, Poole

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-3

Ian: I'm not really sure what you're saying now. What does your last line mean? I wasn't trying to define what 'percentile' means per se in an academic sense, just what its significance is when it has '85th' before it, in the context of road speeds.
Hugh Jones, Cheshire

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-3

Hugh, I accept that it may be possible for someone who regularly analyses the results of speed surveys to estimate spread from a percentile result, but that estimation is coming from the experience of the person looking at the results, it’s not coming from the percentile result, it cannot. In response to your earlier message in this item, I looked at your response in a previous item which you seemed to believe was a definitive explanation of what percentile means, “For hopefully the last time then, when measured and calculated properly, the 85th%ile speed gives an indication of the spread of speeds on a road - and that’s all it indicates”. As we now know, this indicates a number of things, but SPREAD or DISTRIBUTION is the only thing it definitely does not.
Ian Belchamber, Poole

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-2

Alan
You said: "I can assure you that no level of training will stop emergencies happening."
I agree that it will not stop all emergencies, but better/safer/defensive driving can reduce the likelhood of emergencies, and is therefore worthwhile.

You appeared to disagree?

Also, please advise how you propose teaching drivers "how to deal safely with an emergency".
Eric Bridgstock, Independent Road Safety Research, St Albans

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-2

You say “distribution”, I say “spread” to borrow from a famous song, but I think we both mean the same thing. It’s determining the range of speeds on a road and in what proportion. Certainly in the field of vehicle speeds analysis with the pattern of driver behaviour being so predictable, knowing the 50th%ile or the 85th%ile will tell the trained eye what the probable - almost guaranteed - speed “distribution” or “spread” is. Without sounding patronising, it is probably only apparent to someone who does speed surveys day in, day out, but trust me, it works.
You may be familiar with the bell-shaped graph showing vehicle speeds, but whether it’s a ‘30’ local distributor road or the de-restricted scenic road you mentioned, whilst the actual speeds will be different the distribution, or spread, is pretty much the same – it’s the predictable pattern of driver behaviour which does it.
Hugh Jones, Cheshire

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-2

Hugh, in practice, on any road you have a distribution of speeds, perhaps a large number of samples falling within +- 10MPH of average, which might be above or below the limit depending on how the limit is set for the type of road. On some roads (perhaps with sweeping bends and nice scenery) the SPREAD will be greater as faster drivers may want to drive faster and nervous drivers may want to drive slower. This is what spread is, and probably, the greater the spread, the greater the danger (bad overtaking, rear ending, etc). There is absolutely nothing about a percentile result that indicates extent of spread. As I said, and it is easy to demonstrate in Excel you can get the same percentile result from a very narrow range of numbers or an infinitely wide spread of numbers. What a percentile result indicates is only whereabouts the distribution is, it is not a measure or any indication of the extent of the spread.
Ian Belchamber, Poole

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-2

I am puzzled by Alan's response, especially given his CV, of Eric's comment about obviating emergencies.

As Eric accepts, some emergencies do happen even to the best trained drivers but in my experience of 1m miles over 53 years these are much in the minority.

This is confirmed by the 2011 Stats19 causation factor analysis at Stats19 causation at:

http://assets.dft.gov.uk/statistics/releases/road-accidents-and-safety-annual-report-2011/rrcgb2011-04.pdf

listing "driver/ rider error or reaction" as the single biggest group, at 72%.

However the inclusion both of "error" and "reaction" reflects the fact that an emergency caused by one driver's error might be avoided if other drivers' reactions are better, so it is surely not a case of one or the other but of both aspects of training being needed.
Idris Francis Petersfield

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-3

Alan - I would agree with you if you had said that we need better training as well as academic thinking, not instead of it.

However (I once read that "a man of the world is anyone outside an university") I am not keen on the use of the word "academic" in this context when what is needed is not ever-more-complex statistical methods fine-tuned by academics to arrive at pre-determined result but something more down-to-earth including logic, basic arithmetic and an understanding of the important relationships between quarts and pint pots.
Idris Francis

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-2

The protagonists are so in denial they’re tying themselves up in knots.

All one needs to grasp is that whilst the 85th%ile speed is technically the speed that 85% of the traffic doesn’t exceed, it represents lots of different speeds (all lower obviously) as clearly all the traffic does “not exceed” it all to the same degree. In the example I used, if the 85th is 32mph then everyone driving at 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, & 31mph didn’t exceed the 85th%ile speed either – so what? It’s not a measure of safety (I see someone is still desperately clinging to that urban myth) but to the trained eye, it does given an idea of the spread of speeds on the road and the speeds one could typically expect.
Hugh Jones, Cheshire

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-3

Alan
Of course some emergencies will always happen (a tyre blowout on a motorway would be one) but training to improve observation, anticipation and concentration, plus creating safety margins, would have a significant impact on road safety. Those skills can be trained, and applied and honed on every journey. How do you train for dealing safely with emergencies?
Eric Bridgstock, Independent Road Safety Research, St Albans

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-2

Hello Eric,
Obviate is a good word but as a qualified (retd) advanced police driving instructor and currently an examiner for the IAM and member of their regional training team, I can assure you that no level of training will stop emergencies happening, it is the ability to deal with them safely when confronted with them, and that is what is lacking with the standard level of training.
Alan Hale - South Gloucestershire Council Road Safety Team

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+4

Just a suggested change to Alan's comment, which better reflects the advanced driver training that I received from RoSPA about 20 years ago, and which I would like to see more widely taken up ...

"We should seek to achieve a greater and higher level of training for all drivers so that they can OBVIATE an emergency."
Eric Bridgstock, Independent Road Safety Research, St Albans

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-4

Alan, I agree with you, but the problem is, the government don't listen!
Ian Belchamber, Poole

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-1

What a wonderful debate and perhaps instead of exercising our collective academic brain, we should seek to achieve a greater and higher level of training for all drivers so that they can actually deal safely with an emergency. Then we as a group should be lobbying government to return at least some level of policing on to the motorways and A & B roads to deal with the arrogantly stupid who put people's lives at risk.
Alan Hale - South Gloucestershire Council Road Safety Team

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+8

Hugh, if I have 4 samples, 20, 30, 40, 50, what is the 50%ile result, the value of sample within which 50% of the results fall? 30. Now change the 20 to 0, so you have 0, 30, 40, 50. What is the value of sample within which 50% of the results fall? 30. The only thing that effects a percentile result is the number of results above or below, not the spread of the absolute values. I think you’re getting confused with standard deviation, which is a measure of spread.

If you don't believe me, try this:
In excel, put the numbers 2, 3, 4, 5 in column A, cells 1 to 4. In another cell, type =PERCENTILE(A1:A4, 0.5). Now change the 2 to any number from 3 to -ve infinity or the 5 from any number from 5 to +ve infinity, and see what happens to the result - it doesn't change.
Ian Belchamber, Poole

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-4

Mark - the kinetic energy (MV squared) of a projectile rises rapidly with speed but has virtually nothing to do scale of injury in this context. What does is the force needed to accelerate the impacted object during the collision, determined by the impact speed (not speed squared) and the compressibility of the impacting surfaces. Newton's laws apply, but logic is better:

Twin brothers in identical clothes stand, one on a road, the other on a railway line. The first is hit at by a 40mph 1 tonne Escort, the second by a 1 tonne Escort welded onto 40mph coal train weighing 1,000 tonnes (kinetic energy 1m times greater). Their injuries, being due to the same impact at the same speed, are identical. Were they each inside Escorts, the first would be accelerated only to 20mph not 40mph because of momentum conservation, but momentum increases linearly with speed, not by the square of it.
Idris Francis Petersfield

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-7

Hugh - As a professional engineer for 52 years and having spent 1,000s of hours on such data, I repeat, your explanation of the 85th%ile is plainly wrong. If not, explain why.

One number cannot specify a range.

The 85th%ile speed means 85% do not exceed it, not 85% drive at it.

When choosing limits, it is the speed which 85% would not exceed though free to do so.

The 85th%ile was long used to set limits precisely because (at least) 85% of drivers drive safely. It is therefore, by definition, safe.

Setting limits at average speeds assumes that 50% of drivers drive at unsafe speeds, clearly untrue,

Speed v Risk graphs show risk lowest at, or slightly above, the 85th% percentile speed. Faster is more dangerous but so is slower (try 50mph on the M4). If all driving slower speeded up to the 85th%ile, it would not change. There is no constant or identifiable relationship between the various measures of speed that would allow one to be calculated from another.
Idris Francis Petersfield

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-5

As a postscript to my reply about establishing vehicle speeds, I would add that it is crucial to record speeds in free-flowing conditions and with a reasonably sensible headway i.e. excluding tailgaters. Provided it’s done properly, the figures will generally hold good for comparable roads.

As the original news item related to motorways, I would be interested to know if the 85th%ile speed of 79mph mentioned refers to lane number 3 only. If it was the 85th%ile speed of the traffic across all three lanes - as it would have to be, to be true - I would expect it to be lower anyway.

People with an axe to grind tend to put forward notions which are not necessarily based on any sound expertise, but which nevertheless reinforce their point of view and as I have already said, it’s only fair to other readers that someone should paint a more accurate picture.
Hugh Jones, Cheshire

Agree (6) | Disagree (4)
+2

Ian: As I’m sure you’ve realised yourself, the two scenarios you quoted are mathematically impossible. Fairly obviously (I hope) the 85th%ile speed has to include the slowest speed.

For example, if you measured the speeds of 100 vehicles on a stretch of road, the 85th%ile speed is the 85th highest speed, just as the slowest speed and the highest speeds will be the 1st%ile and 100th%ile respectively. If, in a ‘30’ speed limit, the slowest speed was say 16mph and the fastest 52mph, the 85th%ile might be 32mph and this would tell us that typically on this road, 85% of traffic will be in the range 16mph to 32mph (give or take 1 or 2mph) which is why it is an indication of the spread of speeds; you could then establish the speed which the greatest number are driving at, which is never the 85th%ile. (It’s usually around the 50th%ile).
Hugh Jones, Cheshire

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+3

James, if I drive to Birmingham and back in a day as I sometimes do, the difference could be getting on for an hour, and 70 is uncomfortably slow, certainly when the traffic is light. Surely it is nonsense to build safe fast cross country roads and then set the limit based on those who only use them for 10 miles because they wouldn't lose much time?
Ian Belchamber, Poole

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-6

Ian, my comment wasn’t really about the raising or lowering of limits. I was simply making the point that drivers save very little time by travelling at 80mph especially on shorter journeys and once this is realised then some drivers adjust the speed at which they choose to drive.

I agree about the importance of leaving approprite distances between you and the vehicle in front. As far as a blanket 60mph speed limit being introduced, I’m not calling for this and I think it’s safe to say that it's not a headline I think we will see anytime soon.
James Gibson, Leicestershire

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+5

Hugh, can you explain? In the article you refer to, you say “the 85th%ile speed gives an indication of the spread of speeds on a road - and that’s all it indicates”. But you could have a spread of speeds from 50 to 60 with an 85th %ile speed of 51 or 52, 53 etc. MPH, or you could have a spread of speeds from 0 to 1000 with an 85th %ile speed of 51 or 52, 53 etc. MPH. Therefore, it is not a measure of spread at all? Also, how is it that you don’t have an axe to grind, but those who disagree with you do?
Ian Belchamber, Poole

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-5

The "few minutes" argument is misguided.

On a good day, when the M25 and M4 are running well (which does happen occasionally), I can travel from St Albans to Bristol (125 miles) in just about 2 hours. Coincidentally, 2 hours is the recommended maximum time for driving without a break and I have found that I need a comfort break and coffee at that point.

If I were forced to travel more slowly, I would need to include a 20 minute stop, as well as the extra time for the journey.

Not to mention crashes caused by slower drivers losing concentration (ever wondered why lorries drift on to the hard shoulder?).
Eric Bridgstock, Independent Road Safety Research, St Albans

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-8

I don't write my comments to try and win debates or convince other contributors - I do it for the benefit of the wider readership who I hope would appreciate a more balanced and accurate picture of - in this case - the day-to- day reality of speeds on the road. I don't recall anything I've said in the past having been countered by anyone with any real expertise in this field, only those with an axe to grind.
Hugh Jones, Cheshire

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-1

James, by that argument, if you drive at 60, it would only be another minute, and you'd save even more fuel, so why do you not ask for a 60 limit on motorways. 50?
Ian Belchamber, Poole

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-6

I think the comment about how little time is saved travelling at 80mph is really important.

Drivers often think they will get there much quicker by travelling faster. In fact you really do save very little time by travelling at 80mph compared to 70mph. As mentioned you’d save less than 11 minutes on a 100 mile journey and this is of course if a constant speed can be maintained!

I regularly do a short motorway journey - I travel one junction, about 10 miles. Travelling at 80 mph would take me about one minute less and cost me considerably more in fuel. I’m keen to make my money go further, so travelling slightly slower will continue to suit me even if we do see a change to 80mph.

Of course some companies and organisations are also embracing the idea of fuel saving by running green, defensive and fuel efficient training.
James Gibson, Leicestershire

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+4

“Firstly, at 80 mph a vehicle has 30% more energy than at 70 mph and 77% more than at 60 mph. Braking distances and damage directly relate to this.”

Braking distances, yes. But as others have said, many drivers leave inadequate braking distances at all speeds, above and below the limit, and whether or not the limit is perceived to be too high or too low. The best way to solve this is to educate drivers who do not leave adequate braking distances, not just to try to make everyone drive slower. You could reduce the limit to 60 but people would still drive too close and die, at all speeds. Then what? Reduce it to 50? We need more logic in the equation than “the faster you hit the more damage is done” which only tells us we need limits of 0.

Damage, no. The damage relates to speeds at the instant of impact, and as there is always some time between the free flowing speed before the incident started to develop, and the instant of impact, there is far more to it than the speed limit.
Ian Belchamber, Poole

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-3

Hugh. Debates are won on the quality of the argument, not an asssertion that you know what you are doing and someone else does not. Many of your statements have been countered - you need to explain why those counters are wrong to be convincing.
Eric Bridgstock, Independent Road Safety Research, St Albans

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-4

The explanation of the 85th%ile speed I referred to is correct. I've been recording and analysing vehicle speeds for years and it's absurd for a non-professional who hasn't the benefit of this experience, to try and argue otherwise.
Hugh Jones, Cheshire

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-2

I have 3 points to make on this.

Firsly, at 80 mph a vehicle has 30% more energy than at 70 mph and 77% more than at 60 mph. Braking distances and damage directly relate to this.

Secondly, whilst 100 miles at 70 mph takes 1hr 26m, 80 mph only gains you 11 mins and 60mph only loses you 14mins. My 'typical' car does 32mpg at an average 70mph but 46mpg at 60mph. That's £20 vs £14 on petrol - what it would cost at 80mph I'm not sure.

Thirdly, many parts of our motorway network are built at minimum standards for 70mph and if 80mph was made the norm then I expect that there would be a large number of speed restrictions introduced - not back to 70mph, but 60mph or even lower.
Mark Caerphilly

Agree (7) | Disagree (5)
+2

Hugh's "the 85th%ile speed gives an indication of the spread of speeds" is wrong from first principles - no single number can quantify range (highest and lowest) of anything. Nor does anyone claim it means all vehicles are doing that one speed.

He rightly identifies different measures of speed, but is mistaken in claiming, "they all work equally well". One major problems in safety analysis is that no one knows which is most important, and if they did, it would be something else a mile away or the next day.

Nor does knowing one parameter allow others to be calculated, as their relationships varies constantly on different roads at different times - e.g. the average speed of 50 cars doing 50mph is 50mph, but so is the average of 49 cars doing 49mph and 1 doing 99mph - but range, distribution, and risk (in particular) are very different.
Idris Francis Petersfield

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-7

Bob Craven's comment, 'The two thing that haven’t changed for the better is drivers' attitude to speed and far less law enforcement.', I think is spot on. 1). As a former Hendon instructor once said, 'The art is knowing when to go slowly, not knowing when to go fast'. And most drivers don't even begin to understand this concept. and 2) The origin of the police traffic departments was to monitor and supervise road users (and obviously enforce where necessary). I feel the current lack of police traffic patrols is a significant factor in the lowering of driving standards and therefore safety levels because drivers are no longer accountable for their behaviour; they are not ‘aware’ of the police being around. Traffic units set the reference points, both by advice and example – and those reference points just aren’t out there now.
Nigel Albright

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+11

For anyone who's genuinely interested, the Editor kindly published my rather lengthy explanation of what the 85th%ile speed means and what it definitely doesn't mean. It's in the News archive - July 2012 as part of the thread relating to: "Motorists are not safe to drive over 55: Damon Hill". Here is the link: http://www.roadsafetygb.org.uk/news/2264.html
Hugh Jones, Cheshire

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-1

If such a significant increase is acceptable then why not make driving assessment every ten years a mandatory requirement?
Barry, Lancashire

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+5

The figures show that the majority of drivers do exceed 70mph on motorways, the 85th percentile speed of 79mph meaning only 15% exceed that figure.

The 85th percentile issue which Malcolm Heymer mentions in supporting 80mph is relevant in another sense - whatever the limit, the safest speed at which to drive in traffic is not at the lowest speed but close to the 85th percentile (in this context 79mph +/- a few mph). At 70mph I spend far too much time looking in my mirror, at 79mph I am more free to watch developing traffic ahead instead of behind.

Also a 80mph limit would attract drivers away from more dangerous A roads, and higher speeds mean shorter journey times and so less exposure to risk and a higher limit, better enforced, would allow drivers to drive safely as they already do, without the threat of prosecution.
Idris Francis Petersfield

Agree (6) | Disagree (15)
-9

The main problem is not the speed limit. It's how people drive, and that is too close to the car in front. We have too much congestion and maybe opening up the motorway verge would relieve that pressure.

The Highway Code does mention the two second rule but people either have forgotten it or don't bother abiding by it and it could be crucial in the event of an accident. It could save lives. Reading the Highway Code could do many people some good. However it does say that after overtaking one should return to your lane as soon as possible but not cutting someone up. It goes on to say later that if the car in front "cuts u up" you should be the one to slow down as taigating is an offence. So the innocent party is thus guilty of the offence that was caused by someone else's unreasonable behaviour behind the wheel.

Raising the speed limit isn't necessary now with a greater speed tolerance to the offence but if it is increased to 80 then greater speeds will inevitably become the norm, and then what?
bob craven Lancs

Agree (6) | Disagree (2)
+4

80mph was never going to be the motorway national speed limit, the “road safety” industry has invested far too much in the “speed kills” mantra to let that go through.

On the other hand, the coalition may need to ensure that it doesn't look like another U turn and may therefore feel forced to give some selected motorways an 80mph speed limit.

If that's what will happen then why not select as many motorways that are suitable for 80mph as possible, and then randomly select 1/2 of them to be 80mph? I believe that would be Britain’s 1st ever scientific test of any road safety intervention.
Dave Finney - Slough

Agree (8) | Disagree (15)
-7

Another example of the 85th%ile speed being misunderstood/misinterpreted. "Most" people are definitely NOT driving at 79mph - a very, very small percentage are, but most are under the 70mph limit. If there were NEVER any collisions on the motorways then maybe we could ask ourselves if the limit could be increased without consequence, but until that's the case, leave it alone - there's nothing to be gained.
Hugh Jones, Cheshire

Agree (12) | Disagree (5)
+7

How would you manage road safety if the speedometer had never been invented?
Duncan MacKillop

Agree (3) | Disagree (5)
-2

Jools. I would argue that yes, if most people drive at 79mph it means the limit should be upped. We live in a democracy, therefore rightly or wrongly, if the majority of people (over 50%) drive above the 70mph speed limit, it should therefore be changed to reflect that. A democracy shouldn’t have laws that over 50% of people break.

Will an 80mph limit have a positive effect on road safety – I doubt it, but as this is a democracy, the majority rules – no matter how dumb that rule is!
Adam, Hants

Agree (5) | Disagree (15)
-10

Don't you just love the language about being able to "cruise" at 80mph in a modern car. So just because it's easy to do (as is jumping of a cliff by the way) that makes it OK does it? Quite simply our infrastructure and a lot of drivers and our older vehicles are not suitable for this change.
pete, liverpool

Agree (10) | Disagree (6)
+4

The present speed limit was introduced in 1965 following the opening of the first motorway, the Preston By Pass.

I don't know when the present braking distances for cars was established but certainly they have improved since 1965.

I see no problem with increasing speeds on motorways and if I remember rightly this was originally being mentioned at the same time that 20 mph town limits and reduction of general speeds on country roads was being mooted.

The two thing that havn't changed for the better is drivers' attitude to speed and far less law enforcement.
bob craven Lancs

Agree (7) | Disagree (6)
+1

Just because most people drive at 79mph it doesn't mean the limit should be upped. That's like saying, for example, most people drink alcohol over the Govt guidelines so the guidelines should be increased etc. If the Govt really wants to focus on road safety maybe they could introduce compulsory re-testing every 10 years.
Jools

Agree (15) | Disagree (6)
+9