Are you factoring the purchase price of the bus? I believe they cost around $1m. Then there is also having to purchase the yard space to store the bus if that isn't already available. Maintenance and cleaning and associated costs. I'm not sure how often a bus is routinely replaced with a new one.

That is what is implied. A bus should be working 10 hours or more per day for 12-15 years so the per hour cost is around $20.