I know for a fact they run out of buses every day twice a day.Once around 730 am and again around 330 pm.As drivers pull in they send the bus right back out on a new shift.They also call int the shop and ask for buses.The shop spits out what they need and they usually break down within the hour.
8 hr shifts get 30 min meal breaks,but if you are running late there it goes.I did a route over the summer and on saturdays I would always run late the last trip before my break.Try driving 8- 9 hrs without eating anything.