It has been debated for a long period of time about putting seat belts in buses. School buses have been the hottest debate, they use different seating material that is supposed to be more cutioning in the event of a accident. the real debate of seatbelts on school buses is how would you ever be able to keep them fastened w/o kids taking them off, or refuseing to wear them. the other debate is in the event of a emergency evacuation getting kids off who are panicking and stuck in there seats.
On city buses they have started to equip some buses with seatbelts they have had problems but they seem to now have a good system, they are not required to be used but Highly recomended. I haven’t heard any reports on weather people actually use the new style they have come up with.
On the topic of Strollers, it has NOTHING to do with space on the bus. It is a federal Law that strollers and wheelchairs be folded (except when used in a restraint system) its more of a safety issue as well, making sure the stroller is under control and not flying around the bus.
Car seats are not required in buses at this time, however I would recomend sitting on the bus or waiting for the next bus if A seat is not availble. I still think it is common courtesey to give up your seat to someone who has a child or is in there senior years. Personally I won’t sit in a bus/monorail or boat unless everyone else is seated.