[extragoode]

I don't remember what the reasoning was, but I do remember our chief mechanic at our high school (responsible for all 40ish buses and drivers and the resources they consumed) telling us that there was actually reduction in maintenance costs from at least hard braking and he might have even said hard starting. That was almost ten years ago, though, before anyone was worried about how much fuel was being burned.

Edit: I think it might have had something to do with the drum brakes.