Is it legal to have headphones on? (or ear buds in)
{Earphones. Headphones are those things with a band that goes over your head and presses speakers to the outside of your ear. I tend to think of ear "buds" as the round little things that sit in your external ear and earphones as those that go into the ear canal... but definitions on those two vary.}
Both ears- probably (all three- headphones, earphones, and earbuds).
I believe it is legal for a single ear, however..... although that is not what I do.
Doesn't seem safe to me.
In what way? If I were wearing earplugs (which I believe is legal in most states) and had helmet speakers, (which I believe is also legal) it would be absolutely no different or more safe. What matters is volume levels. I can quite clearly hear emergency vehicles, car horns, my engine, etc. Foam ear plugs block more ambient noise than typical earphones.
If I were wearing NOTHING in my ears at all, it would be far *less* safe, because then wind noise is more apt to block other sounds I want/need to hear... plus it leads to fatigue.... plus it can cause hearing damage over the long term.