An articulated bus, also referred to as a slinky bus, bendy bus, tandem bus, vestibule bus, stretch bus, or an accordion bus, is an articulated vehicle, typically a motor bus or trolleybus, used in public transportation. It is usually a single-decker, and comprises two or more rigid sections linked by a pivoting joint (articulation) enclosed by protective bellows inside and outside, and a cover plate on the floor. This allows a longer legal length than rigid-bodied buses, and hence a higher passenger capacity (94–120), while still allowing the bus to maneuver adequately.
Due to their high passenger capacity, articulated buses are often used as part of bus rapid transit schemes, and can include a mechanical guidance system and electric bus or trolleybus.Articulated buses are typically 18 m (59 ft) long, in contrast to standard rigid buses at 11 to 14 m (36 to 46 ft) long. The common arrangement of an articulated bus is to have a forward section with two axles leading a rear section with a single axle, with the driving axle mounted on either the front or the rear section. Some articulated buses have a steering arrangement on the rearmost axle that turns slightly in opposition to the front steering axle, allowing the vehicle to negotiate tighter turns, similar to hook-and-ladder fire trucks operating in city environments. A less common variant of the articulated bus is the bi-articulated bus, where the vehicle has two trailer sections rather than one. Such vehicles have a capacity of around 200 people, and a length of about 25 m (82 ft); as such, they are used almost exclusively on high-capacity, high-frequency arterial routes and on bus rapid transit services.
