Back on track: Lost and found on public transportation

Errors, in particular human errors, play an important role in many aspects of human life, from day-to-day activities to extraordinary situations. This paper describes the theoretical background in the context of Distributed Cognition and the practical design process of an error trapping and mitigation system for supporting seniors' (including disabled seniors) use of public transportation. Data available from the ASSISTANT project support the basic assumption that there are not many things that typically go wrong when people from this target group use buses, trams, trains etc., but that these classes of errors cover a majority of instances. An error model, being a first approximation of a rule-based error capturing and mitigation system, is proposed that is adequate for sparse data and available before the initial use of the system. Several error types, sources of information coming from a Personal Navigation Device and reasonable conclusions are presented and discussed. Furthermore, some examples of an error trapping and mitigation class tree are provided, as well as some aspects of implementing these systems in earlier projects. The on-going ASSISTANT project addresses especially mitigation types and error type classification, which can lead to easier implementation and broader acceptance in a near future.