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.
Double-decker bus
Double-deckers are primarily for commuter transport but open-top models are used as sight-seeing buses for tourists. William Gladstone, speaking of London's double-deck horse drawn omnibuses, once observed that "...the best way to see London is from the top of a bus".