Pennsylvania had a law requiring helmets for motorcyclists until 2003, when it was amended.
But this is largely because there are more riders per capita in states that did not require helmets.
The rule was later changed to require helmets at all times.
No state or resort requires helmets.
To make officers easier to recognize at demonstrations, the department will require helmets emblazoned with identifying numbers.
Now the doctors group is considering endorsing laws requiring helmets, but some ski groups urge caution.
This sometimes results from safety rules that require protective gauntlets and helmets, even when this interferes with historical accuracy.
A number of them require helmets for children 12 and under, while others strongly encourage their use.
While some baseball and softball leagues require batting helmets with face masks, for instance, most make them optional.
In states that do not require helmets, Harley riders seldom wear them.