I drive buses for a job. How long off work will be required after breast reduction?

At the very least you need a week off from work.  Any more time you can get off will help you.  A month would be the upper limit.  Anything between a week and a month is great.

Congratulations on your decision to proceed with breast reduction surgery; this operation tends to be one of the most patient pleasing operations we perform. Every patient responds differently to surgery. Your plastic surgeon will therefore be in the best position to advise you about return to specific activities after the breast reduction procedure. Much of his/her recommendations will depend on exactly how you do (and whether or not you experience any complications) after the procedure.Generally speaking, I would suggest  a MINIMUM of 4 weeks off of the type of work you do. Remember, to keep safety concerns a priority; you will want to be able to respond to an emergency, without discomfort/pain. Best wishes. 

I typically advise that patients stay away from heavy activities for 4-6 weeks after surgery, and that time frame itself depends on how well a patient is healing. Time off of course will depend on your surgeon, but a bus wheel is heavier than a typical car steering wheel (as well as other aspects that need to be considered such as operating levers for opening doors, etc) so I would advise a patient similar to you a minimum of 4 weeks off from work.