The problem: The school bus drivers do not know which students will be absent each day. In the PM, they are dropping off students whose parents may not be home.
Solution: Keeping all the parties in real time connected loop. What platform would you use to solve the problem? An automated call center with dispatching or an App?.
My answer will be short: Definitely an app.
I'll be more than happy to discuss details further.
who is the consumer of this information, the parents, the school system or the bus drivers? Keep in mind that schools won't adopt technology if a large percentage of their families won't be able to use it (i.e. smart phone apps) so maybe sms alerts would have greatest reach.