Joey does this too, he goes through periods where he's better, and then he gets worse.
I've found he's better the more frequently we take walks, and redirecting him seems to work best at alleviating the barking. The other day, he was fine, didn't bark at anyone, then he saw a girl on a skateboard whizzing by, and he barked at her and everyone he saw after that. Redirecting works by just making them look in a different directing, turning them and turning them, until they forget about the person, they were barking at. I've also found that carrying him out the front door and setting him down outside, helps with his excitement level, and the walk is calmer, with less barking.