Here's what the book's website says:
> Correction: That should read "an aeroplane accident". A true comparison with airplane accidents appears on p207, using slightly different statistics.
>
> Note: The probability of dying in a car accident is at least 12 times and perhaps as much as 100 times as great as that of dying from an astronomical event. As road safety improves, this will presumably continue to fall rapidly during the lifetimes of children born today \-- but then, so will the probability of dying from an astronomical event.
So it is, in fact, an error.