I'd be careful about having a dog that small run alongside the bike. But then, if you can go very slow and be able to pay attention to the dog, it might be ok. I live in a place where folks would just as easily run me down in their cars, so I don't take my dog with me on my bike. We have a trailer,but I haven't tried to get him acclimated to it. It wouldn't do much for exercise for him, but he is a herding breed with very high energy. Have you ever heard of dog scootering? There is a company that makes a push scooter with big enough wheels to go over all sorts of terrain, and the dog runs out front on a leash with a bungee in it attached to the front of the scooter.