Just a few quick points:

1) There's really no need to respond to the recently posted studies, because on this thread dozens if not hundreds of studies have already been posted, generally "proving" whatever point the poster wanted them to. So despite whatever our favorite studies claim, none of us really know how much safer, if any, bicycle helmets make us.

2) Ignoring a debating point because it is not directly relate to cycling is a dodge and everyone here knows it.

3) Despite all the safety features already placed in modern cars, some 30,000 Americans are killed in them every year, many from head injuries. So the claim that car drivers don't need helmets because cars already have safety features is kind of dumb.