page_title: Proof-of-payment
section_title: Advantages and disadvantages
hierarchical_section_title: Proof-of-payment / Advantages and disadvantages
context_page_description: Proof-of-payment or proof-of-fare is an honor-based fare collection system used on many public transportation systems. Instead of checking each passenger as they enter a fare control zone, passengers are required to carry a ticket, pass or a transit smartcard to prove that they have paid the valid fare. Fares are enforced via random spot-checks by inspectors such as conductors or enforcement officers, to ensure that passengers have paid their fares and are not committing fare evasion. On many systems, a passenger can purchase a single-use ticket or multi-use pass at any time in advance, but must insert the ticket or pass into a validation machine immediately before use. Validation machines in stations or on board vehicles time stamp the ticket. The ticket is then valid for some period of time after the stamped time.
  This method is implemented when the transit authority believes it will lose less money to the resultant fare evasion than it would cost to install and maintain a more direct collection method.
context_section_description: Advantages of proof-of-payment include lower labor costs for fare collection, simpler station design, easier access for mobility-impaired passengers, easier access for those carrying packages or in case of an emergency, and a more open feel for passengers. On buses, proof-of-payment saves drivers the time needed to collect fares, and makes it possible for all doors to be used for boarding. Validated tickets can double as transfers between lines.
  Disadvantages include potentially higher rate of fare evasion, reduced security on station platforms when no barrier is used, increased potential of racial profiling and other unequal enforcement as "likely fare evaders" are targeted, and regularly exposing passengers to unpleasant confrontational situations when a rider without the proper proof is detained and removed from the vehicle. Visitors unfamiliar with a system's validation requirements who innocently misunderstand the rules are especially likely to get into trouble.
caption: The Caltrain commuter rail line along the San Francisco Peninsula posts a proof-of-payment logo on signs throughout stations, reminding riders to purchase tickets before boarding.