I would like to suggest that this picture would be improved without the mirror. While the school buses alone are not interesting, you have the beautiful backdrop of the mountains, which are obscured by the mirror. (imho)
Definitely a back to school sort of topic (and that looks like a fairly pretty place, as far as school bus parking lots go). The mirror I find distracting, presentting blurry busses in the foreground against crisply focussed ones in the background - I think this might have been stronger without it. The sky's awfully bright/washed out, but I don't see how that could be countered without darkening the buses too much.
I think that the mirror makes this photo interesting, whereas otherwise it would just be boring. But the sky is also blown out, and the colours seem like you added too much brightness.
This is a great bus shot. Seems like I've been to this spot myself :) Don't know how you did this without getting yourself in the shot. Very nice composition!