I wanted to send out a counter argument to this article claiming that
cycling (and we can probably infer skating too, though I guess drivers
are often so surprised to see you on the road, they're likely to give
you a pretty wide berth) with a helmet is actually "more dangerous":
http://news.bbc.co.uk/1/hi/england/somerset/5334208.stm

Check out this report from the NYC DOT on bicycle accidents in the
city over the past 10 years. Of 225 fatalities, 97% of the riders were
not wearing helmets, and 74% involved a head injury. Drivers may be
more reckless around you if you're wearing a helmet (because you look
more competent or something) -- but you're still at a much higher risk
of serious injury and death without the helmet.
www.nyc.gov/html/doh/downloads/pdf/episrv/episrv-bike-report.pdf

(One could also conclude from the nycdot's data that nyc is actually a
pretty safe place to bike comparatively. The accident rate per million
is the same as 'elsewhere' in the country, while there are twice as
many cyclists per million out there. (#2 under the 'key findings'
section))

Bethany