Road Deaths increase in NW

Ontherivet77
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Location: Lancashire

Road Deaths increase in NW

Postby Ontherivet77 » 7 Sep 2020, 4:15pm

It appears that Road Deaths are up 42% in the North West. GMP are blaming it, partly, on head case boy racers speeding whilst the roads were freer of traffic during lock down. Anyway, it's a depressing statistic and hopefully not one being repeated in other regions of the UK.

https://www.theguardian.com/uk-news/202 ... g-lockdown

Jdsk
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Re: Road Deaths increase in NW

Postby Jdsk » 7 Sep 2020, 4:20pm

Are the raw data available?

Jonathan

Ontherivet77
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Location: Lancashire

Re: Road Deaths increase in NW

Postby Ontherivet77 » 7 Sep 2020, 4:29pm

Jdsk wrote:Are the raw data available?

Jonathan


Total won't be confirmed until next year as far as I'm aware, I'm just taking the headline info from the article.

Jdsk
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Re: Road Deaths increase in NW

Postby Jdsk » 7 Sep 2020, 4:30pm

Thanks

Jonathan

thirdcrank
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Re: Road Deaths increase in NW

Postby thirdcrank » 7 Sep 2020, 4:47pm

It's only a few weeks since the police inspectorate published a report - linked on here by Mike Sales from a report in the self-same Grauniad - saying that a reduction in policing was causing a rise in casualties.

The discussion got a bit bogged down in the matter of speed cameras as cash cows.

The report linked in the OP hints that this is a national trend, rather than one restricted to the North West.

The police spokesperson suggests that what might be termed "boy racers" are behind this.

viewtopic.php?f=6&t=139326#p1508569

As I pointed out in that thread, HM Inspectors see boy racers as "vulnerable."

axel_knutt
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Re: Road Deaths increase in NW

Postby axel_knutt » 7 Sep 2020, 6:47pm

Smeed's Law.
“I'm not upset that you lied to me, I'm upset that from now on I can't believe you.”
― Friedrich Nietzsche

Jdsk
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Re: Road Deaths increase in NW

Postby Jdsk » 7 Sep 2020, 7:02pm

Apart from the question of whether it exists isn't this the opposite... traffic volumes went down and deaths/unit time went up?

Wikipedia:
https://en.wikipedia.org/wiki/Smeed%27s_law

Jonathan

thirdcrank
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Re: Road Deaths increase in NW

Postby thirdcrank » 7 Sep 2020, 7:11pm

Yes.

It seems to me that in normal conditions, traffic congestion is the main thing keeping speeds down, especially away from roads with fixed speed cameras.

After reading the OP in this thread, I wondered about GMP priorities and I found this from the chief constable, early in lockdown. Although he was primarily talking about the pandemic, he referred specifically to how quieter roads had resulted in more speeding.

Coronavirus: Police chief Ian Hopkins angered by speeding drivers


https://www.bbc.co.uk/news/uk-england-m ... r-52300428

Mike Sales
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Re: Road Deaths increase in NW

Postby Mike Sales » 7 Sep 2020, 7:17pm

Jdsk wrote:Apart from the question of whether it exists isn't this the opposite... traffic volumes went down and deaths/unit time went up?


Wikipedia:
https://en.wikipedia.org/wiki/Smeed%27s_law

Jonathan


Smeed's Law observes that the death rate per vehicle decreases as vehicle miles increase. Usually, traffic density inceases as time goes by, of course, but the effect on German road casualty rates of the decrease in numbers of cars caused by WWII is quite striking. The rate per vehicle post war was similar to the rate some years before the war, when vehicle numbers were similar. Subsequently the rate decreased again as traffic density increased.
The empirically derived Law relates casualty rate to traffic density, not time.
I have read one expression of the Law which notes that accidents in a T junction increase not with the increase in traffic movements through it, but with the root of the increase.

Jdsk
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Re: Road Deaths increase in NW

Postby Jdsk » 7 Sep 2020, 7:23pm

Mike Sales wrote:
Jdsk wrote:Apart from the question of whether it exists isn't this the opposite... traffic volumes went down and deaths/unit time went up?

Wikipedia:
https://en.wikipedia.org/wiki/Smeed%27s_law

Smeed's Law observes that the death rate per vehicle decreases as vehicle miles increase. Usually, traffic density inceases as time goes by, of course, but the effect on German road casualty rates of the decrease in numbers of cars caused by WWII is quite striking. The rate per vehicle post war was similar to the rate some years before the war, when vehicle numbers were similar. Subsequently the rate decreased again as traffic density increased.
The empirically derived Law relates casualty rate to traffic density, not time.
I have read one expression of the Law which notes that accidents in a T junction increase not with the increase in traffic movements through it, but with the root of the increase.

That Wikipedia article has it as describing the effects on both fatalities per capita (which is what I was referring to) and fatalities per vehicle. Is that definition of what the "law" is disputed?

Thanks

Jonathan

Mike Sales
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Re: Road Deaths increase in NW

Postby Mike Sales » 7 Sep 2020, 7:30pm

Jdsk wrote:That Wikipedia article has it as describing the effects on both fatalities per capita (which is what I was referring to) and fatalities per vehicle. Is that disputed?

Thanks

Jonathan



No.

I was referring to your use of deaths/unit time as a measure. I suppose deaths per head per year or whatever is relevant. It is always necessary to use the same basis when comparing, but Smeed's point is about traffic density affecting casualty rate, not time.

Jdsk
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Re: Road Deaths increase in NW

Postby Jdsk » 7 Sep 2020, 7:34pm

I was assuming that the denominator population was constant in this case.

How can you measure fatalities per capita in any useful way without it being per unit time?

(In the original news report that was "in the same period last year"... a unit of time.)

Jonathan

Mike Sales
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Re: Road Deaths increase in NW

Postby Mike Sales » 7 Sep 2020, 7:43pm

Jdsk wrote:I was assuming that the denominator population was constant in this case.

How can you measure fatalities per capita in any useful way without it being per unit time?

(In the original news report that was "in the same period last year"... a unit of time.)

Jonathan


Of course the rate is measured per unit of time, as I just wrote, as well as per head, but Smeed suggests that when the conditions are equalised in this way, as of course they have to be, then traffic density seems to be inversely related to accident rate.
It really would not make much sense to say that twice as many accidents occured if you were comparing double the length of time, would it?
By comparing "the same period" in two different years the time element in itself is removed as a cause of the change.

Jdsk
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Re: Road Deaths increase in NW

Postby Jdsk » 7 Sep 2020, 7:47pm

That's what I'm saying.

So in this report the metric was number of deaths in six months or whatever. And if you wanted to compare that with another observation that was over a year then you'd normalise both to deaths/ year or deaths/ month. Or some other unit of time.

Deaths per capita isn't useful without that time element.

Jonathan

Jdsk
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Re: Road Deaths increase in NW

Postby Jdsk » 7 Sep 2020, 7:51pm

Please could we now return to whether the observed change is as predicted by "Smeed's Law" or the opposite?

Jonathan