<VV> Idle vs shut off - very limited Corvair, if any

[Grant Young]

I am hoping that somewhere amongst our group is someone who has worked out this problem or deals with cost numbers with large gas and diesel engines. As with most school districts across the US, ours is dealing with budget cuts that were promised would never come if we approved a lottery and reduced property taxes. That being said, we are trying to determine if the adage about it being cheaper to idle a school bus than shut it off and start it again still holds true at our current gas and diesel prices. Our school buses idle for as long as 10-15 minutes while waiting for students to load after school. Has anyone run the ballpark numbers recently that can help me out? If the data is interesting and sweeping enough to cover Corvairs, please post, but otherwise please send me a private reply. (Yes, I know the major cost problem is educating the thousands of illegal students we have, but being a teacher, I am not allowed to go there, so the gas savings is fine :-).
Thanks,
Grant