I agree with you that having all cyclists wear helmets wouldn't strictly increase overall safety (maybe people will switch to driving...), but I think you're di

I agree with you that having all cyclists wear helmets wouldn't strictly increase overall safety (maybe people will switch to driving...), but I think you're discounting the utility of helmets even where collisions with motorized vehicles isn't the primary risk. Here are stats from the Netherlands [0]. Looks like there are about 9000 serious crashes each year that don't involve motor vehicles, with about 2500 cases annually of head/brain injury. That's actually a much higher rate than for crashes involving cars in the Netherlands, presumably because of the infrastructure and culture.... [0]: https://www.swov.nl/en/facts-figures/factsheet/bicycle-helmets https://www.swov.nl/en/facts-figures/factsheet/bicycle-helme...