Originally Posted by I-Like-To-Bike

The statistics quoted in the OP and that I specifically referenced are from a study of Football Helmets. Perhaps you should read the words, and not just look at the pictures.
"How Much Protection Do Football Helmets Offer?

Not much, at least against blows to the side of the head, according to a study that will be presented at an upcoming meeting of the American Academy of Neurology. Scientists testing how 10 popular football helmets fared against 19.3-kilometer-per-hour impacts found that they reduce the risk of traumatic brain injury by an average of 20% compared with not wearing one."