@brianb I velcro a bluetooth speaker to my headset. The volume is set low enough that road noise from cars is louder.
Also works for taking calls. "Hello! What? I can't hear your! Hello? I'll call you back later!"
@brianb In my experience, music is motivating from a workout point of view, but immersive and thus dangerous (i.e. you lose awareness)... podcasts are safer, but have the downside of not letting you mind wander... when I resist the headphones and listen to nothing except my own thoughts I get the best of both worlds, I am active physically while I rest and restore mentally.
@brianb
A bit on the pricey side, but I strongly recommend the Bose Frames Tempo. They are not headphones, but sports sunglasses with built-in speakers and polarized lenses.
The sound quality is decent, up to about 25ish MPH (40ish kmh), and I can still hear the traffic around me.