ticket controller

Proof-of-payment (POP) or proof-of-fare (POF) 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 paper ticket, transit pass, transit smartcard — or open payment methods such as contactless credit or debit cards (if applicable) — after swiping or tapping on smart card readers, 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 validati...