The human auditory system has evolved so that it can cope with multiple inputs. So an ear bud in one ear does not mean that you will miss other sounds. I still find a simple FM radio to be great when there is a strong enough signal and it will run on a single AAA battery for many days. This is what I use on the bike along with the iphone for podcasts and music. I could use the iphone for the radio too, but it eats up battery life.
https://www.universal-radio.com/cata...alty/2850.html