I have taken the view that helmets don't usually help much, but that people often perceive wearing a helmet as being the definition of safety, rather than obeying the rules of the road and paying attention to the road and what is going on around you. In my view, those are far more important than what you have on your head.
Personally, I haven't seen anyone saved thanks to a bike helmet, but I have seen people get into minor accidents because they were ignoring traffic rules and not paying attention to the road. Lots of people in the US seem to treat bikes as more of a kid's toy, to be cruised around the local neighborhood without a care in the world. They don't have the damage potential or expense of cars, but they are still vehicles that are many times faster and less maneuverable then you are on your feet, and so deserve your respect and attention.
Personally, I haven't seen anyone saved thanks to a bike helmet, but I have seen people get into minor accidents because they were ignoring traffic rules and not paying attention to the road. Lots of people in the US seem to treat bikes as more of a kid's toy, to be cruised around the local neighborhood without a care in the world. They don't have the damage potential or expense of cars, but they are still vehicles that are many times faster and less maneuverable then you are on your feet, and so deserve your respect and attention.