Laimis rašė:
> Daugiausia eismas vyksta keliuose, kur važiuoja ir automobiliai, ir
> dviračiai, ir traukiniai, ir arkliai, dar vaikšto pėstieji.
> Vienokios eismo sąlygos (ir rizika) yra Balbieriškyje, kitokios --
> Vilniuje piko metu intensyvaus eismo atkarpoje.
> Noriu pasakyti (o taip teigia ir, sakykime, įdomioji-praktiškoji kitų
> šalių statistika; tai, kaip ji yra pateikiama/interpretuojama), kad
> apibendrinta/lyginamoji tikimybė nukentėti važinėjant automobiliu yra
> *kartais* didesnė už tikimybę nukentėti važinėjant dviračiu.


Laimi, atleisk, bet rašai labai painiai – daug ženklų „/“ ir skliaustų, 
todėl sakiniai sunkiai suvokiami. Kalbant apie saugumą, štai čia yra man 
labai patikęs įtikinantis skaičiavimas:
http://hembrow.blogspot.com/2010/08/brain-injuries-and-dutch-cyclist.html

Brain injuries and the Dutch cyclist
An Australian reader pointed me at this document which is about head and 
brain injuries amongst Dutch cyclists. Yes, there are also some people 
in NL who think that helmets for cyclists are a good idea.

To me, the thing to do is to look at the numbers. The overall risk to 
Dutch cyclists (it's on page two of the document) of a "head/brain 
injury" is 153 per billion kilometres ridden. That means that one such 
injury is one per 6.5 million kilometres ridden.

On average, every Dutch person cycles 2.5 km every day. That's the 
highest figure for any population in the world. If we assume that people 
cycle every day of their lives to the age of 80, and that they cycle 
that 2.5 km every day of their life, they will ride a bike for a total 
of 73000 km during their lifetime. Divide it into 6.5 million and you 
find a figure that a typical Dutch cyclist can expect a "head/brain 
injury" once every 90 lifetimes.

Note that it doesn't say how serious the injuries have to be in order to 
be included. However, it does give total numbers of head/brain injuries 
per year as 550 + 1600 = 2150 which is more than ten times the total 
deaths of cyclists per year from all types of injuries. For the sake of 
making the maths easy, let's lazily (and very inaccurately) assume that 
every death when cycling is due to a head injury. We then find that the 
risk of death due to head or brain injury when cycling is actually 
around once per 900 lifetimes.

Also, note that the article points out that cycle helmets can only 
reduce the rate of deaths due to head injuries by 29%. So, if a helmet 
is worn by that typical Dutch cyclist, it will save his/her life every 
3100 lifetimes or so.

Death occurs once in every lifetime. Other causes of death are 3100 
times so significant, even here where there is more cycling than in any 
other country, and even when we deliberately make the inaccurate 
assumption that cyclists never die of any type of injury - and this is 
in a country where 93% of the population rides a bike at least once a week.

A contrast with another cause of death:

A couple of days ago I saw some other statistics, about a much more 
common cause of death and injury. This covered the risk of car crashes 
to Britain's children. In this post is the alarming statistic that one 
in 27 children in Britain, more than one in every classroom, can be 
expected to be killed or injured in a road crash by the time they are 16.

Think about it. If the risk is similar in other age groups, then there 
is a chance of one in five that you will be injured or killed in a road 
crash during your lifetime. That's a risk due to motor vehicles which is 
many times greater than that faced by cyclists in the Netherlands not 
wearing a helmet.

Britain's roads are actually amongst the safest in the world, for 
drivers. However the risk of death or serious injury from road crashes 
elsewhere is higher in every other country than this one, where there 
are more cyclists than in any other country.

Previously I covered the efforts that car manufacturers have put in to 
make driving appear safe.

Also... 2.5 km per day may not sound much, but this is the highest 
average cycling per day per person figure for any country in the world. 
It's the average distance cycled for absolutely everyone, all age 
groups, through the entire year, averaged across an entire lifetime. By 
comparison, English speaking countries all hover around 0.1 km per day 
by bike per person (look it up if you don't believe me). In all places, 
keen cyclists of course cycle a lot more than the average. Long distance 
journeys by bike are also more common in the Netherlands than in any 
other country.