What a terrifying situation for all concerned. Just out of interest, do most children get to school by bus? Or do parents take them? Can many kids walk to their local school?
That's not an easy question to answer. The school official said there are 200 drivers for this district, so I'm assuming it's a large district with kids living some distance from the school. Perhaps highway driving is necessary.
In the U.S., kids get to school many different ways, depending on the size of their district, urban vs rural, how far away they live, whether there is a very busy highway or road to cross, whether or not public transportation is available, parent's schedules, whether the family has a car, etc. In general, public schools are required to provide transportation to and from school. For many districts, dedicated school buses are used. In others, kids are provided with a low cost, or no cost, public bus pass.
Special education kids with serious disabilities are provided specialized transportation with trained attendants, most of the time separate from regular school buses (for children in wheel chairs or other mobility issues, or emotional/ behavioral/ intellectual disabilities).
Depending on the availability and willingness of parents, walkers often have what is called a "walking school bus", where parents escort a group of young students for safety. Districts decide which zones (and sometimes age groups) will and will not receive bus services, and which are "walkers". Walkers can ride bicycles in some districts. For example, one neighborhood in my area has bus service for elementary students, but the same area requires middle and high schoolers to be walkers (or find another way to get to school). For many high schoolers over age 16, a car is a longed-for luxury/ rite of passage, and if they or a close friend has one, they often want to drive to school. (And pay to park!)
Parents can always drive their kids and drop them off, but most schools nowadays have very regimented pick up and drop off locations and procedures, due to modern school security measures. Cars are not generally allowed to drop off kids in the same area as the buses. In my district, parents cannot enter the school to walk their child to class unless they have prior permission and a pass pre-issued from the office.The beginning and end of the school day has been identified as a vulnerable time when kids could be abducted, or unauthorized people could get inside, or teachers distracted by talking to parents, so many districts in our area prohibit parents from coming inside without pre-planning.