Professor Risk

Some risks are very straightforward, e.g. the risk of losing when buying a lottery ticket. Others are not so simple, and if you know more, the headline figure can be considerably modified. For example, the low risk of having an accident in a car depends on the low accident rate and high mileage on motorways, so off the motorway, the risk will be higher than the figure shows. And every activity doesn't just have one risk, often it will have several risks - and sometimes benefits that can offset the risks. For example, driving a car carries a risk of killing or seriously injuring another person, which is almost absent from walking or cycling. Doing this might not shorten your life directly, but would, for most people, result in considerable emotional distress, even if the other party seems to be mainly to blame. And if cycling is your only exercise, not doing it would increase risks of ill health unless you compensate with other activity. The risks of cycling also depend very heavily on location (to take an extreme example, they are very much lower in Holland than in the UK) and age - the older, the safer. Apart from this, surely the numerical risks associated with driving, cycling, and motorcycling must depend heavily on careless and reckless drivers, cyclists and motorcyclists, who will presumably have the greatest risk of accidents. I wonder if the relative risks of the different activities are the same for those who are careful?