Originally Posted by
Six jours
That's splitting the hair very finely, especially in light of your claim that "The helmet is primarily for hitting the ground and that's generally going to happen regardless of how the accident occurs. Unless we're thrown up in the air we'll hit the ground with the same impact whether we're hit by a car, or riding 30 mph, or fall over at a light."
That's a fact, not splitting hairs.
Risk of injury is overall higher when a car hits you. The particular injuries resulting from the head hitting the ground are about the same however, and the helmet affords the same protection from that in either case.