Where is the least bumpy spot on a school bus?

[Dysnex]

What is the least bumpiest spot on a bus? Specifically a yellow, single-decked, "transit" school bus, although I think this could apply to most, if not all, buses.

 

[Mech_Engineer]

The middle, equidistant between the front and rear axles.

The bumpiest spot is the back of the bus behind the rear axle.

 

[brewnog]

Somewhere around the bus's centre of gravity.