Interchange with same operator

Clearly, where an operator has introduced a system for continuing travel authority within his group of services then the fare validation provided against the initial purchase will be accepted by the second vehicle in a linked journey. The necessary controls, therefore, relate to ensuring that only the authorized travel is made and that the fare validation for the first boarding is then cancelled after its use such that the authority expires after the subsequent boarding.

Such controls are relatively easy to incorporate in either electronic or stored-value travel authorizations, but some form of mechanical cancellation is required for printed tickets. Failure to cancel the first stage of a travel authorization, where this is made a duty of the passenger, then becomes a fare evasion offence.