Maths Problem

[Racing roadkill]

The cyclist is 22/7ths.

 

[DaveReading]

[QUOTE 4718118, member: 9609"]if 1% of all miles covered on the roads is by bicycle
and 18% of all KSI are to cyclists

How much more at risk is someone on a bicycle to someone in a motor vehicle ?

How do you do the maths here ?[/QUOTE]

You can't do any maths until you define the question more precisely.

"How much more at risk?" could be considered as either a comparison between an hour on the bike and the same amount of time behind the wheel, or between covering the same distance on two wheels vs four.

Clearly there will be two, different, equally valid answers.

 

[srw]

The one that has the most logical train of thought supported by the best evidence.

And you should not believe anyone, you should decide to accept a worldview with a degree of trust commensurate with your own understanding of the subject and the degree of rationality and evidence in the point of view.

It's simple really, but people just don't want to think - they just want to know who to follow.

At least if you're following blindly there's a moderate chance of following someone who knows what they're talking about. Worse is the sort of person who thinks half-heartedly and carelessly, comes to a very firm, fixed conclusion, and refuses to move from that conclusion however much people who have slightly more of a clue point out the flaws in their thinking.

 

[Tin Pot]

At least if you're following blindly there's a moderate chance of following someone who knows what they're talking about.

That's a patently ridiculous position.

Assuming a random position because you don't trust your own judgement, you would be better off holding no position at all.

EDIT

Hang on, you nearly had me. This is the Cafe. The rest of this can happen in The Other Place.

 

[jefmcg]

[QUOTE 4718118, member: 9609"]the official figure seems to be 8x and I am sort of getting 22x[/QUOTE]

Here's one link, which doesn't give the specific statistics cited: https://www.gov.uk/government/uploa..._data/file/533293/rrcgb-main-results-2015.pdf

I've just skimmed this thread, but I'm confused as to the problem.

Isn't that the numbers calculated by @User9609?
KSI for cyclists 5824+31=5855 KSI/1,000,000,000 miles
KSI for car passengers/drivers = 273+2 =275

5855/275 = 21.3

So cycling is 21.3 times as dangerous per mile as driving a car per mile, very close the Reiver's back-of-the-envelope calculations.

Or I am missing something?

 

[slowmotion]

I've typed this before, but it's kind of relevant.

Some years ago I was tidying the shed. I pulled on a pedal which was tied to its mate and hung over a hook. The other pedal came free of the hook at tome speed and smacked me inbetween the eyes, just over my glasses. Within seconds I couldn't see, as both eyes were full of blood from the cut. Lady Byegad transported to hospital where they cleaned me up and superglued the cut.

That's when the fun started.
Nurse, 'How did the accident happen'
Me. 'I pulled on pedal in the shed and it the other one came away and smacked me in the forehead.'
Nurse, 'OK, a cycling accident.'
Me, 'No, it happened in the shed and the pedal wasn't even attached to a bike.'
More of the same ensued, until a senior nurse turned up and made an executive decision that it was a cycling accident.
I got very angry and also got nowhere on this. So back in that year at least one recorded cycling accident wasn't! My final appeal that had I hit my head with a ski, would she record it as a skiing accident (in NE England in July) was duly ignored.

Did you get told off for not wearing a helmet?

 

[lutonloony]

has anybody allowed for tandems?

 

[Milkfloat]

has anybody allowed for tandems?

I think @jefmcg did as her chart is titled 'per passenger mile'. The only passengers on a bike are on the back of tandem

 

[DaveReading]

I think @jefmcg did as her chart is titled 'per passenger mile'. The only passengers on a bike are on the back of tandem

And I rarely carry a passenger when I'm walking ...

 

[srw]

I've just skimmed this thread, but I'm confused as to the problem.

View attachment 342328

Isn't that the numbers calculated by @User9609?
KSI for cyclists 5824+31=5855 KSI/1,000,000,000 miles
KSI for car passengers/drivers = 273+2 =275

5855/275 = 21.3

So cycling is 21.3 times as dangerous per mile as driving a car per mile, very close the Reiver's back-of-the-envelope calculations.

Or I am missing something?

Could well be. I'm afraid that as soon as he refused to provide a source for his 8x figure, refused to accept a national statistic because all politicians lie, refused to accept that expertise is relevant, refused to entertain the possibility that he wasn't posing a simple maths problem and suggested that I was stalking him I lost interest.

If you accept that KSI stats per mile are the unique measure of "dangerousness" (I don't, and some of the reasons are in this thread) then you've just calculated something about "dangerousness". But, to coin a phrase, it's a little more complicated than that.

Now, I'm sure there are snowflakes in the café for whom that's far too much thinking already. How about a nice cup of twea and some bikkits?

 

[byegad]

Did you get told off for not wearing a helmet?

That was asked, when I pointed out that even had a been wearing a styrofoam hat the pedal would have still hit me rather than the hat there was much sucking of teeth.