bt behavior off-leash

I was wondering if anyone has trained their dog so they no longer need a leash? Geech is pretty good most of the time; he doesn't run away if he's not on his leash but I don't trust him farther than the front yard. He tends to go crazy outside and do that thing where he gets that insane look in his eye and starts tearing around in circles! I get really worried when we're outside that he will do this and run out in front of a car. He has also just discovered birds and squirrels and loves to chase them down. He doesn't listen to me when I call him, but he will respond to my husband -- who doesn't think he needs to always be on a leash. Mostly he is good, but like I said, he has those crazy moments where I can't control him. I get really anxious that he will run into the street. He doesn't know any commands at all!

Has anyone been able to train their dog so that you don't need a leash anymore? Do SIT and STAY really even work when your BT is spazzing out?

Thanks!