Guess what? I actually agree with the OP.
To Feif, and everyone else talking about extra chumras. You mean well but you miss a crucial point. A woman hired by a bus company is not hired based on whether or not she is a prutza (a lascivious woman), but based on whether or not she is qualified to be a bus driver. Sitting next to a woman on the bus is one thing, but sitting next to the same woman every single day could lead to something, especially if she is a prutza. Did you ever think about the last kid to get off the bus, sitting and shmoozing with his bus driver every night? Did you ever think about how likely it might be for something to happen if she is indeed a prutza, even remotely attractive, and he is seventeen or eighteen (the OP is talking about mesivta, not elementary school)?
Let’s just say I know someone personally who was in that exact situation, and it led to something which would give you goosebumps. And I have no reason to think that this case was a freak incident. Hence my opinion.