I note that the links you provide indicate no research to support the belief that helmets are particularly helpful for the general public. (They do suggest that they can be helpful for children.)

Interesting that the NHTSA document your link leads to says "Universal bicycle helmet use by children 4 to 15 would prevent 39,000 to 45,000 head injuries" (no stats for adults given). The document says "Bicycle related head injuries are expensive because these injuries can endure and may require treatment for a lifetime." It's interesting because these types of statistics are the basis of the campaign for universal helmet laws for bicyclists. Yet, according to the Brian Injury Assoc. of America and the CDC: 280,000 head injuries are suffered every year in car accidents. At an average of $4 million per TBI that's costing us $1.12 TRILLION in lifetime health care costs! Where are the cries for universal helmet laws for ALL car drivers??? [Links: CDC More ... , $4MIL per TBI More ... , $60BIL per year More ... , TBI's by state More ... ]

Apparently the "researchers" haven't published the method they used so their findings cannot be considered useful science or a credible basis for a helmet law. Most helmet studies are suspect because of the application of poor statistical analysis techniques.

For complete examination and critique of the most commonly cited studies visit the site of the Bicycle Helmet Research Foundation at: More ...