Double-decker bus
With the exception of coaches, double-decker buses are uncommon in the United States. Many private operators, such as Megabus, run by Coach USA, employs double-decker buses on its busier intercity routes.
Transit bus
Transit buses can be single-decker, double-decker, rigid or articulated. Selection of type has traditionally been made on a regional as well as operational basis; however, with the advent of global manufacturing, all of these types can be seen in the same location or country. Depending on local policies, transit buses will also usually have two, three or (for articulated) four doors to facilitate rapid boarding and alighting.