I've worked a lot with my dog on commands while running, and he seems to have learned pretty well what to do when we go out for a run.
He knows not to cross in front of me, not to slow down, not to head off in his own direction, and to listen to me for what is coming up next.
I would imagine verbal commands while with a bike would work the same. Like Elk said, a treat bag of something YUMMY and VALUABLE is great to have with you, so you are more interesting than anything else on your run/ride. (we have many cats in our apartment complex... competition for Stinky Dog's attention can be fierce sometimes!)
"If Americans want to live the American Dream, they should go to Denmark." - Richard Wilkinson