Drove a school bus. The primary rules are made by the district, and the district CAN overrule a driver. However, the driver is given a lot of latitude because his/her main job is to operate the bus safely, and keeping order can be very distracting and dangerous.
For the same reason, I had a bus 'monitor', another adult, whose job was to keep order. Most school districts provide monitors in my area, particularly in districts where students are unruly (my kids were a mixx of Hispanics and Whites, from working class backgrounds, and from neighborhoods and families with a lot of known gang activity and rivalries: spontaneous fights and violence could break out based upon these factors. And this was among ELEMENTARY SCHOOL children!)
Still--I wish I understood the rule against reading better: I would have loved a busload of kids sitting quietly and reading books.