OK, so if wearing cycle hemets was made compulsory, and it reduced the number of people cycling to say 20% of the original number, it would in a very narrow sense save some lives.
But is such a drastic reduction in cycle use, overall, a good thing ?
Not a good thing overall, although that no doubt depends on which report you read, but here's one from 2010:
Snippet:
Data synthesis
We quantified the impact on all-cause mortality when 500,000 people would make a transition from car to bicycle for short trips on a daily basis in the Netherlands. We have expressed mortality impacts in life-years gained or lost, using life table calculations. For individuals who shift from car to bicycle, we estimated that beneficial effects of increased physical activity are substantially larger (3–14 months gained) than the potential mortality effect of increased inhaled air pollution doses (0.8–40 days lost) and the increase in traffic accidents (5–9 days lost). Societal benefits are even larger because of a modest reduction in air pollution and greenhouse gas emissions and traffic accidents.
Conclusions
On average, the estimated health benefits of cycling were substantially larger than the risks relative to car driving for individuals shifting their mode of transport.
(Note that this is the non-helmet wearing Netherlands, and it's still advantageous to cycle with all that extra risk.)
Disclaimer: I haven't read it all the way through.
www.statista.com
