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Comment by donaldc | Hacker News Reader

According to the World Health Organization, more than 1.2 million lives are lost every year in road traffic accidents.

That is an incredible number. 1.2 million out of 7 billion. If the average person lives to age 70, that means that on average, one has a 1.2% chance of dying from a traffic accident.

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Not to mention most of those 7 billion likely don't drive, which effectively increases your risk if you DO drive.

Having been in 3 major car accidents, one for each decade I've been alive, where I was at the wheel only once and alcohol was not involved in any of them... I have to say I do not find these numbers at all surprising. I would have guessed higher.

Another way to look at it is you've been in 3 major accidents and survived all of them, so it may be that the chances of having a fatal accident may be lower than you thought?

Unlikely. You're probably under the belief that That Can't Really Happen To You, just like almost everyone. At least experiencing the high risk of it a few times probably will help you to consider seriously the height of the risk.

That said, being human you might overcompensate.

And that doesn't count the incredible number of serious-but-not-fatal accidents which surely cause much injury.

I'm not a statistician, but something about that doesn't sound right to me.

  >>> p = 1.2e6/7e9 # Probability of dying in any one year
  >>> scipy.exp(log(1-p)*70) # Probability of NOT dying 70 years in a row
  0.98807069644395429
  >>> 1-_
  0.011929303556045712

There might be some roundoff error in the exponentiation. I am too lazy to check.

Great, thanks for the clarification.

Out of interest, why do you prefer the second line to

    (1-p)**70

? Is there some kind of improved numerical stability?

I thought it sounded high too, but it's correct.

Does that number count bus accidents?

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