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.
Single-deck bus
In regions where double-deckers are not common, the term "single-decker" may lack common usage, as in one sense, all other main types of bus have a single deck. Also, the term may become synonymous with the name transit bus or related terms, which can correctly be applied to double-deckers too.