distance as the regular route. Fare payment Fare payment is done via: Smart card single or multi-ride coupon/ticket cash (none required: Zero-fare bus) and is done upon: Pre-payment, done at ticket machines located at the bus stops or at other locations, before getting on the bus. boarding departing both, e.g., after crossing fare zone boundaries in transit, via an attendant or bus conductor (mostly obsolete systems) Doors Depending on payment systems in different municipalities, there are widely different rules with regard to which door, front or rear, one must use when boarding/exiting. For rear doors, most buses have doors opened by the driver controls or patron (with touch-to-open, motion sensor or push bars). Most doors on buses use air-assist technology, the driver controlled doors, use air pressure to force them open, patron-operated doors, can push them open, however, the doors are heavy, so the touch-to-open or push bar mechanism, sends pressurized air to open the doors. Most doors will signify that they are unlocked and open with lights, this gives guide to those who are going up or down the door steps to not trip and fall. Unlocked or open doors, will trigger a brake locking mechanism on the bus to prevent it from moving while someone could possibly be entering or exiting the bus, when the door is closed, the lock will release, this is mostly implemented on rear doors, not really on front doors, since the driver will be paying attention to the front door. Types 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. In cases of low-demand routes, or to navigate small local streets, some models of minibus and small midibuses have also been used as transit type buses. The development of the midibus has also given many operators a low-cost way of operating a transit bus service, with some midibuses such as the Plaxton SPD Super Pointer Dart resembling full size transit type vehicles. Developments Due to their public transport role, transit buses were the first type of bus to benefit from low-floor technology, in response to