>>but then there's this psychological thing: aside from driving through an auditory illusion, they ride through a safety illusion and take more risks. It's disputable how does this move the odds - reckless with helmet vs careful without.
>
>I think that's a ridiculous argument. It's like suggesting people drive more recklessly because they wear seatbelts.
>
>Doug

Not really, for instance, drivers of 4x4 tend to drive more recklessly because they feel safer. This phenomenon has been studied in a variety of situations and we often behave in counter-intuitive ways. Dan Ariely discusses this in his book Predictably Irrational: The Hidden Forces That Shape Our Decisions - http://tinyurl.com/d227t5 . These phenomenon are also part of the field of behavioural economics .