"vastly worse wearing a helmet, at least the SA full-face helmets"
Which is why the research into this topic focuses more on headbands, which mostly protect the forehead, than the entire head. See http://www.copenhagenize.com/2009/10/australian-helmet-scien... for a summary of Australian research and a sketch of the head gear. They quote:
> But more impressive were the estimates of introducing protective headwear for car occupants. The authors of the report estimated that the annual reduction in harm would be in the order of $380 million. The benefit of padding the head is that the head is protected from strikes with unpadded automotive components, exterior objects and in vehicles that predate any eventual introduction of padded interiors."
Which is why the research into this topic focuses more on headbands, which mostly protect the forehead, than the entire head. See http://www.copenhagenize.com/2009/10/australian-helmet-scien... for a summary of Australian research and a sketch of the head gear. They quote:
> But more impressive were the estimates of introducing protective headwear for car occupants. The authors of the report estimated that the annual reduction in harm would be in the order of $380 million. The benefit of padding the head is that the head is protected from strikes with unpadded automotive components, exterior objects and in vehicles that predate any eventual introduction of padded interiors."