IMPACT: Helmet

I.
While the jury seems to be out on motorcycle helmet laws, there are no excuses for bicyclers not to be wearing helmets.
http://www.helmets.org/stats.htm
While there is no excuse, here are ten popular ones for not wearing a bicycle helmet.
http://www.rtis.com/reg/bcs/org/bvcweb/helmet.htm

II.
Based on an internet article about motorcycle helmet laws by Jonathan P. Goldstein, Ph.D.
"A Trade-off Between Head and Neck Injuries Confronts a Potential Helmet User".
With regard to motorcycle helmet wearing, I came across this "article". It doesn't seem to have been published in any journal but can still be taken at face value as someone's opinion. The position taken is one that explains, a helmet, while protecting the fallen rider from a head injury creates an increase in severity of neck injury past a certain speed of 13mph secondary to forces generated from a bounce of the pavement.
The author also concludes, helmet use has no statistically significant effect on the probability of death. This is of course because of, head protected or not, there is significant trauma sustained elsewhere. Goldstein finds that only bike speed and blood alcohol level were statistically implicated in fatality.
Who am I to tell people to wear helmets? I'll leave that one to the state legislature. My advice is to abide by the laws and more importantly, from a safety standpoint, avoid motorcycles.
http://www.bikersrights.com/statistics/goldstein/goldstein2.html

III.
Here's a study looking back at 36 persons killed in motorcycle accidents that found riders with open-face helmets (19 cases) were significantly more likely to have sustained severe head and neck injuries, especially brain contusions (bruises), than were riders with full-face helmets (17 cases).
Hitosugi M, Shigeta A, Takatsu A, Yokoyama T, Tokudome S. Analysis of fatal injuries to motorcyclists by helmet type. Am J Forensic Med Pathol. 2004 Jun;25(2):125-8.

IV.
This study from University of Pennsylvania and the Philadelphia Veterans Affairs Medical Center shows while states with full helmet laws do maintain a lower death rate than those states without. This position is not supported with statistical significance meaning there is a possibility these conclusions were drawn by chance and not actually influenced by a helmet.
Branas CC, Knudson MM. Helmet laws and motorcycle rider death rates. Accid Anal Prev. 2001 Sep;33(5):641-8.