You don't even need to go this far.

Passenger cars-- heck, even coach buses-- are engineered for passenger comfort and convenience.

City buses are engineered to secure the driver against passengers, to be simply maintained and hosed out as needed, and to accommodate overcrowding standing-room-only discomfort. Seats are hard, leg room is deficient, shoulder room is deprived, and that's even before we talk about trying to time an irregular arrival or departure time on a wobbly bus schedule.

You only ride a bus if you're indifferent to personal inconvenience, have firm principles, or have no choice.