However, if it is a bus and there is a bus stop at the beginning of the next block, there is a good chance the bus will pull to the right to get to the bus stop, leaving you stopped and trapped behind it. In that case I ride behind the center of the bus so that I can move left and pass the bus as it slows and moves right.
I need to exercise caution in such case, too (when passing a stopping/stopped bus on its left): For one, to make sure to watch for cars coming from behind, some of which do not slow down; also, there is a small chance the bus may not stop long after all (no/few passengers getting on) and could quickly leave the bus-stop while I have not completely passed it.