The number of publications about mobility as a service (MaaS) has increased rapidly in the past years, spreading into various fields. In this paper, a total of 127 scientific publications about MaaS are reviewed and categorized into an overarching thematic framework in order to highlight key areas of research and further potential. Three research questions are highlighted in this review: (1) which topics are discussed in the existing MaaS literature? (2) what are the main results in the specific fields? and (3) where are gaps for further research? Publications have focused substantially on the topics of the market, users, data and technology, and the impact on the transportation system. The review shows that, regarding the concept, multi-level approaches have been established for the organization and cooperation of the actors involved, showing different levels of integration of public and private actors on a regional and supra-regional level. Various groups have already been identified as potential users, but the relatively low willingness to pay and the requirements regarding the individualization of mobility services pose problems that have not yet been solved. There is also a constant and unsolved challenge regarding the sensitive motion data that must be stored and processed. Significant research is still needed, including assessments of the impact of MaaS and what effects the service will have on the established use of transport modes, as well as how packages need to be designed and priced in order to optimally reach users.

The past years brought massive changes in the transport and mobility market, accompanied by the rise of concepts such as Mobility as a Service. An enormous increase in publications on this topic documents the growing importance of multimodal mobility solutions for daily transport, but practical applications of the concept are rare. In addition to challenges in the organization of players, this is due to an unclear conception of the service offer and which particular services should be included to what extent. This paper presents the results of an empirical study in the city of Dresden, Germany, where participants could choose out of various bundles of mobility services in a conjoint analysis. The survey provides evidence for the great importance of public transport for the evaluation of mobility bundles as well as for the benefit-enhancing effect of car and bike sharing. A comparison among different user groups reveals a very homogeneous picture of mobility plans, which, however, only partly reflects actual behaviour.