>>1434227>>1434233Give me a minute to rant about the current state of *ideologically driven* science. Researchers do studies like "Children's bicycle helmets effective in impact and crush tests, study suggests" by the American Association of Neuro Surgeons who drop objects only from 6 and 9 inches and then claim that "helmets reduce the forces from an oblique impact at 30mph to the forces from one at 7mph". The government then runs with it and makes policy on it and people treat it like fact.
There are several problems with this:
> 7mph to 30 mph is a 328% increase in speed but only increases impact forces in *oblique* impacts by around 90% because most of the energy is coming from the fall not the speed.>It is not clear you can extrapolate into 30mph collisions from a 9 inch drop.So why is oblique impacts important, well it's because *helmets do effectively nothing for lateral or head on collisions* especially at speed. In tests helmets increased collision times substantially (I will give you that, I was not expecting so much of a difference), from about 0.002s to 0.01s during an impact at 15kph. However forces were only reduced from 600g to 500g, which is little consolation when skulls fractures occur around 250g! The difference would be even less at higher velocities as the helmets simply cannot absorb additional energy. (Bicycle Helmets: Head Impact Dynamics in Helmeted and Unhelmeted Oblique
Impact Tests)
Going back to oblique impacts (the most common type of impact), current research has concluded that they do actually prevent head injuries from low speed oblique impacts but conclude that "Few helmets provide good protection against oblique impacts
. Some of the included helmets are
designed to absorb rotational forces. These helmets generally perform well" (consumer testing of bicycle helmets, 2017)
