Lady D - I get your point. The costs to others, in terms of the potential consequences of driving a car are not insignificant and there is a huge responsibility therefore, which goes with driving. I think the majority of people recognise this, which is why we have a system of driving tests, licencing and policing. These things don't exist in relation to cyclists which is a recognition that it is a less potentially destructive activity. But that is not to say that there are no responsibilities which come with riding a bike. Having lights on at night is one of them.