These rules will naturally be for the state and district that I drive in. I believe that most other districts will follow these rules also. To be absolutely sure, just call your transportation director at your school and request a copy of the guidelines. I will list the rules and add my own comments for clarification. I am basing the need for this on questions and feedback over the years.

 Pupils shall arrive at the bus stop before the bus is scheduled to arrive. (five minutes early is our guideline)
  Pupils must wait in a location clear of traffic and away from the bus stops. (remember the sliding bus in the winter?)
 Behavior at school bus stop must not threaten, life, limb or property of any individual. (see Stop Behavior)
 Pupils must go directly to an available or assigned seat.
 Pupils must remain seated keeping aisles and exits clear.
 Pupils must observe classroom conduct and obey the driver promply and respectfully. (see Bus Behavior)
 Pupils must not use profane language.
 Pupils must refrain from eating and drinking on the bus except as required for medical reasons. (you must let the driver know first what you must do.
 Pupils must not use tobacco on the bus.
 Pupils must not have alcohol or drugs in their possession on the bus, except for prescription medication required for the student.
 Pupils must not throw or pass objects on, from, or into the bus. (includes everything!)
 Pupils must carry on the bus only objects that can be held in their laps. (this is a difficult one, with instruments and sports equipment but it is necessary.)
 Pupils must leave or board the bus at locations to which they have been assigned unless they have parental and administrative authorization to do otherwise. (we require written permission, this includes friends going home on a different bus-no note, no ride. The easiest way is two notes, one for the teacher and one in the backpack for the driver-eliminates "my teacher kept it" or "I left it in the room")
 Pupils must not put head or arms out of the bus window. (if sitting properly, this shouldn't happen)
 Guidelines will be formulated for the use and storage of equipment and other new means of assistance required by handicapped students.
 Proper steps will be taken to collect, store, and use medical information related to pupils known to have medical problems which may require driver attention. (we can't help if we don't know)

As you can see, there have been rules established to hopefully ensure that things go smoothly without injury to anyone. The list could go on and on about each individual item but you must be practical and make some determinations yourself from this list of rules. When in doubt, ask the driver or call transportation.