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This means that the document the traveller presents does not carry any ticket information at all, but it is rather a certificate of competence to dispose disposition the rights contained within a central repository. This certificate does not have to be personal and should therefore be considered as identifying the repository - rather than a particular individual.
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The decisive difference between such ticket-centric systems and strict ID-based systems is that, in the latter case, the traveler traveller does not carry any ticket information at all. The document the traveler traveller presents must either be validated by information from an underlying system or accepted as it is based on its mere existence.
The BoB project has defined ID-based travel systems as follows:
Travel where the traveler traveller does not carry any ticket or ticket information, but instead a documentary proof entitling the traveler to dispose traveller the disposition of the rights attached to this document and in a central repository which is managed by an underlying ticket and fare collection system.
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