Traditionally, urban bus operators have collected fares in cash for each trip. Some limited mechanisation has occurred in ticket issue at stations. Partly for reasons of operating convenience, there has recently been a shift to simpler fares and prepayment, notably through the introduction of ‘Travelcards', that is, tickets or passes permitting unlimited use of the network (or zones thereof) for ... [Show full abstract] a defined period. These cover both all-bus systems, and bus/rail networks (such as the West Midlands PTE system). They are now used in all main British conurbations, following introduction of the London Transport bus/rail Travelcard in May 1983. The Travelcard in effect redefines the ‘product’ being sold. Instead of the public transport service being perceived as a series of separate journeys, payment is made periodically for use of the network as a whole. Cost perception is thus put on a similar basis to that for the private car. The marginal money cost for each trip becomes zero. Interchange penalties associated with re-booking are eliminated. Payment may be made by cheque or credit card, rather than cash, further changing the perception of costs. Product quality is also enhanced through speeding up of services (one-person- operated buses), and enabling the user to select the quickest and/or most convenient route in a network by removing the interchange penalty.