When I commute to work I always listen to my iPhone's music to keep the ride interesting. About half of it is on a limited access path, the other half is on roads. I use standard sony (http://www.amazon.com/Sony-MDR-J10-H.../dp/B000092YR6) headphones plugged into my iPhone, and when I get occasional calls I can answer. I have a backpack that has a spot for a phone on the strap, but during the summer months I use an exercise arm strap that holds the phone.

I get variable results in regards to call quality. Sometimes I can have perfect calls for the entire trip, even if it's very windy. Other days it will be totally calm and I won't be able to talk to the person on the other end.

Regarding safety, the speed of cars on the road I travel would essentially be impossible to avoid by the time I hear them so I might as well be accessible.