150 mph M25 8-10

[Kawasicki]

La Liga said:

The benefit of the travelling time doesn't justify the increased risk.

There'd have to be clear benefits to the fundamental purpose of the road network. The 10s of millions of economic damage through the extra fatal / serious RTCs wouldn't be offset.

Are we here again?

If there is clear economic and humane evidence against increasing the speed limit, then that same evidence would lead us to believe that the current speed limit is too high. Should we reduce the limit to 50mph, 40mph, 30mph...what is the economic value of a life versus the efficiency of an economy?

If the speed limit was 50mph today, you would argue that an increase to 70mph couldn't be justified.

[Devil2575]

Kawasicki said:

Red 4 said:

I doubt you'd make the comments you have on this thread if you had more experience of the driving standards in this country than me.

My opinion/comments are backed up not only by experience, but by basic statistics, i.e. UK roads are relatively safe.

Your experience and the statistics seem to clash.

Despite being on the other side for much of this debate i'm with Kawasicki on this one.

I don't care who has more experience of the roads because personal experiences doen't make good evidence. KSI stats are cold hard figures and can be compared, personal experiences are subject to bias and based purely on opinion and so can't. They are very unlikely to have been quantified in any way and are limited by an individuals ability to accurately recall. So you drive down the M1 one day and you see a few cars where the driver does something you percieve to be dangerous. Was it actually dangerous? is there a standard scale of danger? How many cars did you see doing dangerous things? What percentage of all the cars you saw were dangerous? Was this an exceptional day or do you generally see more of less cars? etc etc.
All personal experiences give us is a potential hypothesis. For it to become anything more than tis it needs to be backed up by data.
If people are driving badly then it will show up in the accident stats. An individual or even a small group of individuals could get away with bad driving. After all a large part of most accidents is just down to dumb luck. Thee needs tio be a car on the other side of the blind bend for there to be a crash if you round it on the wron side of the road for example. However with a large enough data set the overall trend will reflect the general standard of driving, within the other factors that dictate the relative risk.
Our roads are some of the safest in the world, even relative to other highly developed countries, so it follows that we must have relatively competant and safe drivers.

I don't see much sense in trying to judge average drivers by some elite standard, not when our roads are as safe as they are.

I don't see an overall justification for unlimited roads because I think that KSI stats would go up and this isn't politically acceptable. I also think that a change to unlimited roads would result in carnage, but not because we aren't good enough drivers, it's just that we don't expect it. We're not generally prepared to deal with other drivers doing something vastly out of the ordinary and as such I think it would cause chaos initially. However there is no reason why it would in the long term work out any less safe that Germany. But that is still less safe than we currently are.

[Neonblau]

Kawasicki said:

Less time used traveling.

Why is the current motorway/dual carriageways limit 10mph above the single carriageways limit?

There might be less time for a few individuals, but not for the bulk and not likely to provide economic benefit enough to justify the increased risk.

It's many years since I studied it but I'm sure Queueing Theory and/or Wardrop's principles apply to road speed, as opposed to individuals and speed limits. Simply put these state that x vehicles moving on y road (size of road, control factors - including limits, environment etc) will have the optimal speed determined by a range of factors. A few individuals travelling significantly quicker or slower than the mean will simply be statistical outliers and will not impact the speed of the flow. The speed limit is simply one of the factors and from memory, certainly back in the 1980s it was not one of the high scoring factors and in many cases was actually determined by some of the other statistically significant ones.

It's actually quite a complex and interesting subject and there are many more aspects to it than discussed on this thread. I only studied some theory as part of a wider subject but I'm sure there will be some PH experts who can expand.

[Kawasicki]

Devil2575 said:

I don't see an overall justification for unlimited roads because I think that KSI stats would go up and this isn't politically acceptable. I also think that a change to unlimited roads would result in carnage, but not because we aren't good enough drivers, it's just that we don't expect it. We're not generally prepared to deal with other drivers doing something vastly out of the ordinary and as such I think it would cause chaos initially. However there is no reason why it would in the long term work out any less safe that Germany. But that is still less safe than we currently are.

I can't disagree with your logic, in fact I agree with everything you've written but the politics is not something I support. In the future (Notwithstanding WW3) the politics of safety is unstoppable, and personal choice/risk assessment will be weakened. I've got nothing against health and safety, it just that there doesn't seem to be a balancing force against it. I've worked in companies where H&S paralysed the workforce, even then there wasn't an organised counter argument.

[anonymous-user]

Kawasicki said:

Are we here again?

If there is clear economic and humane evidence against increasing the speed limit, then that same evidence would lead us to believe that the current speed limit is too high. Should we reduce the limit to 50mph, 40mph, 30mph...what is the economic value of a life versus the efficiency of an economy?

I've already answered this.

We're not talking, in this thread, about smaller increments i.e. 5/10/15/20 MPH, we're talking about no limits.

You can't re-frame the argument away from the extreme when it suits.

The cost / benefit balance alters to a much smaller degree around the areas we have now. 10 MPH here and there doesn't make a huge difference. It shifts to a much greater degree when we're talking no limits in the favour of the "cost".

I can't make it any more simple.

[Kawasicki]

La Liga said:

've already answered this.

We're not talking, in this thread, about smaller increments i.e. 5/10/15/20 MPH, we're talking about no limits.

You can't re-frame the argument away from the extreme when it suits.

The cost / benefit balance alters to a much smaller degree around the areas we have no and whether or not 10 MPH here or there matters. It shifts to a much greater degree when we're talking no limits in the favour of the "cost".

I can't make it any more simple.

So you're not against increasing the limit to 80mph?

[anonymous-user]

Kawasicki said:

So you're not against increasing the limit to 80mph?

Compliance around the 70 limit allows people the realistic scope to drive around 80.

The report produced when we (the UK) were considering it concluded the risks didn't justify the benefits.

I think given the compliance thresholds and realistic enforcement policies, I'm happy for it to remain at 70.

[Kawasicki]

La Liga said:

ompliance around the 70 limit allows people the realistic scope to drive around 80.

The report produced when we (the UK) were considering it concluded the risks didn't justify the benefits.

I think given the compliance thresholds and realistic enforcement policies, I'm happy for it to remain at 70.

I'd love to see the science behind that report. I'm also not sure I agree with the logic of a speed limit that about half of car drivers don't stick to.

[anonymous-user]

I don't think it's anywhere near half. The point is there's a degree of compliance and tolerance with any limit that allows people a little more scope than the absolute figure. If you raise it to 80, then some will drive faster. It's not as simple as that, but that's an overview of compliance.

The DFT report is here: http://news.bbc.co.uk/1/shared/bsp/hi/pdfs/23_02_1...

[Kawasicki]

La Liga said:

I don't think it's anywhere near half. The point is there's a degree of compliance and tolerance with any limit that allows people a little more scope than the absolute figure. If you raise it to 80, then some will drive faster. It's not as simple as that, but that's an overview of compliance.

The DFT report is here: http://news.bbc.co.uk/1/shared/bsp/hi/pdfs/23_02_1...

Thanks for the report, I must admit this comment on the cost/benefit calculations really made me laugh...this bit sums it up nicely, and I quote...


"Journey times (an average increase of three minutes per hour of journey, but this
effect is not included in the calculation as it is the loss of an illegally obtained benefit)"



So the only measurable benefit to increased speed limits is excluded from the calculation. I mean really, somebody thought that was logical!?!

They could justify a 1mph speed limit with that logic,

"we will ignore any time saved from travelling at 2mph instead of 1mph (an average saving of 30minutes per hour journey)...this
effect is not included in the calculation as it is an illegally obtained benefit)"



Regarding half of cars speeding...

From

https://www.gov.uk/government/statistics/free-flow...

On motorways, 49% of cars exceeded the 70 mph speed limit in 2011, unchanged from 2010.

[anonymous-user]

There's enough people who want higher limits / no limits. There must be some peer reviewed studies to support those changes. Where are they?

Kawasicki said:

Regarding half of cars speeding...

From

https://www.gov.uk/government/statistics/free-flow...

On motorways, 49% of cars exceeded the 70 mph speed limit in 2011, unchanged from 2010.

Oh, at some point. No surprise. I thought you meant during some normal motorway situation as is if they were being held back by the current limit from making reasonable progress, which was probably wrong on my part.

[LoonR1]

Kawasicki said:

Regarding half of cars speeding...

From

https://www.gov.uk/government/statistics/free-flow...

On motorways, 49% of cars exceeded the 70 mph speed limit in 2011, unchanged from 2010.

That's a bit of a tenuous quote. I wonder if a statement that half of men admit to sleeping. With a girl under the age of 16 would freak you out?

It's taken no account of the fact they did it once and they were 15 too.

[Kawasicki]

La Liga said:

oh, at some point. No surprise.

I think it means that about half of the cars on a free flowing motorway will exceed the limit.

[Kawasicki]

LoonR1 said:

That's a bit of a tenuous quote.

Are you alluding to the fact that the cars are only measured on non congested motorways?

Do you think that the figure is unrealistic?

[LoonR1]

Kawasicki said:

Are you alluding to the fact that the cars are only measured on non congested motorways?

Do you think that the figure is unrealistic?

No. Read the rest of my post and quote it as well, as it explains it quite clearly.

[Kawasicki]

LoonR1 said:

No. Read the rest of my post and quote it as well, as it explains it quite clearly.

No, I'm still lost, this isn't a survey of what people have admitted to doing, this is an analysis from measured speeds.

[anonymous-user]

Kawasicki said:

La Liga said:

oh, at some point. No surprise.

I think it means that about half of the cars on a free flowing motorway will exceed the limit.

Maybe so, but the degree of exceeding depends on the posted limit (when it's not ridiculous).

I'm not massively bothered about 5-10 MPH here and there. It's the proposal of an extreme 'no limits' that I am not for.

[LoonR1]

Kawasicki said:

LoonR1 said:

No. Read the rest of my post and quote it as well, as it explains it quite clearly.

No, I'm still lost, this isn't a survey of what people have admitted to doing, this is an analysis from measured speeds.

So it's a snapshot?

[CAFEDEAD]

LoonR1 said:

So it's a snapshot?

Yes, of ~755000000 vehicles.

[Kawasicki]

LoonR1 said:

Kawasicki said:

LoonR1 said:

No. Read the rest of my post and quote it as well, as it explains it quite clearly.

No, I'm still lost, this isn't a survey of what people have admitted to doing, this is an analysis from measured speeds.

So it's a snapshot?

Well I'm not sure what duration the measurements were taken over, I doubt they would go to the trouble of logging vehicle speeds over a very short duration. Maybe over a month, or longer.