I agree with Denise, sitting in an office chair with only one ear bud in, listening to NPR is enough to distract me into not "hearing" someone speak to me, so I don't believe that any earphones, no matter how low they are set can ever be safe while riding a bike. In many places it is a moot point in any case, because it is illegal to ride a bike, on the street or on a path, while wearing headphones.