Do you have to stop on a four lane street with a school bus?

Yes, you do have to stop on a fourlane street with a bus.

It really depends on the driving laws of the State you live in. Here in Illinois, according to the Rules of the Road book put out by the Secretary of the State of Illinois, you do not. After discussing with several Police officers, they are not aware it is legal to do so.

I would recommend checking the rules of the road published by your state.