ISO/TR 17185-3:2015 is to define high level general requirements of journey planning systems by standardizing use cases.

This part of ISO 17185 defines basic requirements for implementing the journey planning system, from the viewpoint that the public transport users should be provided with convenient tool to make his or her journey more efficient ones. In order to realize the desirable journey planning system, public transport information has to be efficiently processed and provided to public transport users in an appropriate way by using currently available regional standards.

This part of ISO 17185 does not standardize specific information interfaces such as data format or a stop point numbering system and so on but currently available regional standards established by regional and national groups are suggested to be applied.

ISO 17185 is composed of the following parts:

- Part 1: Standards framework for public information systems: (International Standard)

- Part 2: Data and Interface standards catalogue and cross reference: (Technical Report)

- Part 3: Use cases for journey planning systems and their inter-operation: (Technical Report)