Amenable to security controls

Direct profit margins in commercial urban passenger transport services may only be in the order of a 10% return on sales, so revenue losses through passenger fraud and/or staff peculation can be very damaging. Even where any revenue shortfall is made up from the public purse, the fare system should be designed so as to minimize losses.

The range of potential frauds, and the ingenuity of passengers in exploiting any weaknesses in the system, is immense. Pre-printed tickets are vulnerable to forgery, and present a storage risk because of their monetary value. Periodic passes and concessionary-fare authorizations are vulnerable to fraudulent application and use. Human involvement in the sales, authorization, and inspection of tickets introduces the possibility of collusion between passengers and agents in avoiding payment of the correct fare and enacting the appropriate penalties. Agents may devise ways for the fraudulent operation of ticket-issuing machines.

Electronic fare payment and travel validation systems have a higher inherent level of security at the personal level, but could prove vulnerable to a sophisticated hacking attack. The likelihood of this might be low, but the impact would be immense.