chasm54

You are almost certainly wrong about that.

The figures seem to show that increasing use of helmets has not resulted in a reduction in the already low rate of injuries to cyclists. Now, I'm not so foolish as to believe that helmets never prevent injuries, so how are the figures to be accounted for? It can only be that either helmeted riders are more likely to have accidents than they were when nobody wore helmets, or that in some cases helmets give rise to injuries that wouldn't have been sustained by the unhelmeted.

Neither of these propositions is ridculous. It's quite likely that there is a degree of risk compensation involved, either on the part of drivers or cyclists or both. It's well documented in many areas of human behaviour that those who feel protected behave ore dangerously than those who don't. Add to that the fact that people overestimate the protective effect of helmets, and underestimate the importance of skills training, and it is quite possible that the adoption of helmets has increased the frequency with which people fall off.

And the injuries that really do damage to your brain are rotational. Your head is dragged round and your brain bounces around inside your skull. There is real possibility that helmets can make these injuries more likely. First, your head is a bigger target with a helmet on, you are likely to sustain glancing blows that would have missed your head. More important, the helmet will create friction with whatever it hits and tend to pull your head around. One of the good things about scalps is that they don't do this, they tend to tear and your head slides rather than rotates. Messy and unpleasant, but better for the brain.

None of this is demonstrable beyond reasonable doubt on the evidence we have before us. So you are free to regard it sceptically. But then you still have to answer the question, how come more helmet-wearers doesn't translate into fewer injuries?