Can you drive a bus and pick up passengers on the streets?

You can drive a bus, however you cannot pick passengers up, though that would be pretty dang awesome

You can steal a bus and pick up passengers at bus stops. Unfortunately, if you steal an occupied bus (meaning that you hijacked a bus with a driver and passengers in it) the bus driver will chase you to the ends of the earth to get his bus back. When you pick up passengers at the stops, they will pay you 5$, which makes using the bus seem like a mini-game of sorts. The animation of the passengers getting on is a little awkward in Grand Theft Auto IV. In GTA4, the people stare at the bus doors and patiently wait for them to open, which seems almost like the Force from Star Wars. Sometimes, the A.I will glitch out, and the passenger will accidentally steal the bus from you and drive away. This was patched in GTA5. Also keep note that you can only pick up passengers in single player, not multiplayer. In multiplayer, you can pick up other players though. But be aware: the reason the GTA community is so bad is because most other players don't care about each other, so most other players with a modded controller (that is if you're playing on Xbox) will steal your bus rather than get on. You can not steal other players vehicles online, you can only get in with them. That's why you need mods (or a modded Xbox controller) to hijack other players online.