Double-decker bus

A double-decker bus is a bus that has two stories or decks. Double-decker buses are used for mass transit in the United Kingdom, an iconic example being the red London bus. Double-decker buses are also used in many other cities around the world.
Early double-deckers put the driver in a separate cab. Passenger access was via an open platform at the rear, and a conductor would collect fares. Modern double-deckers have a main entrance door at the front, and the driver takes fares, thus halving the number of bus workers aboard, but slowing the boarding process. The rear open platform, popular with passengers, was abandoned for safety reasons, as there was a risk of passengers running and jumping into the 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, «...the best way to see London is from the top of a bus»