FAO, David Cameron. Some nice lines from the BMA's 1992 book on cycling, concluding remarks on helmets and other "roles for the individual", p94:
In turn, this points to two conclusions: first, that it is dangerous to pass all responsibility for road safety on to those who are most vulnerable. Rather, it is those who are the source of most danger, the motor-vehicle drivers, and those in a position to alter the traffic environment, for instance through the medium of 'traffic-calming', who should have the primary responsibility for ensuring cyclists' safety. Secondly, it could be argued that it is immoral to allow people, especially children, to have bicycles and to encourage them to acquire skills to use them, but then to leave them to exercise these skills in environments that can be highly dangerous.