There was a study that showed having pedestrians wearing cycle helmets would save 100x as many lives and drivers 10x as many - as making cyclists wear them.
Partly this is because there are a lot more pedestrians/drivers than cyclists but also because above children speed a bike helmet doesn't do much for you. If you are cycling at 20-30mph you need the same helmet as a motorcycle doing the same speed.
ps. this was also before airbags became ubiquitous. a lot of non-seatbelt wearing drivers die of head injuries in common low-speed impacts.
It's true I always wondered why "small motor bike" drivers had such an hardened and heavy helmet compared to "styro-foam carbone fiber" made bike helmet.
I read some the abstract of the studies contradicting the health benefits of a helmet and the studies contradicting those very studies. I am convinced that helmets benefits outweight naked head benefits. The rare case where someone has a neck injury directly because of the helmet seems to be extremely rare.
Partly this is because there are a lot more pedestrians/drivers than cyclists but also because above children speed a bike helmet doesn't do much for you. If you are cycling at 20-30mph you need the same helmet as a motorcycle doing the same speed.
ps. this was also before airbags became ubiquitous. a lot of non-seatbelt wearing drivers die of head injuries in common low-speed impacts.