## 4 Discussion  
This paper proposes an initial draft for a catalogue of scenarios that might help when creating design solutions for the remote operation of AVs. It is published preliminarily with a remaining need for evaluation, validation, and modification in future iterations. Even though the scenarios presented here originate from diverse sources, particularly real-world labs, idiosyncrasies of other contexts of use will need to be considered by revalidating and extending the catalogue. In spite of these constraints, the catalogue fulfills several purposes. First, it serves as a starting point for _designing novel interfaces_ for remote-controlling highly automated vehicles--and has, in fact, already done so. Based on these scenarios, the authors of this paper designed an HMI for a workplace for remote operation in an online study with experts employed by control centers in public transport [21]. Incorporating the results from the evaluation study, a workplace for remotely assisting AVs has been set up at DLR's Braunschweig premises. Second, the catalogue is suitable to _test and validate HMIs_ in teleoperations of means of public transport. For instance, the workplace described above will be tested and validated using the catalogue of scenarios presented here. Thanks to the workplace's integration in realistic road simulations and DLR's fleet of highly automated vehicles [31], a validation study with high ecological validity will be carried out. Using both quantitative, performance-based indicators and qualitative interview and questionnaire methodology, a group of experts from public transportation facilities and associations and other potential users of a remote operation workplace was exposed to a selection of the scenarios presented here [32]. Hence, a bidirectional relationship is established between the scenarios and the workplace: Not only will the study guide the process of improving the workplace for the needs of the remote operator to execute their tasks safely, effectively, efficiently, while ensuring an optimal task load, keeping the operator in the loop and preventing fatigue and monotony. It will also help reassess and refine the compiled scenarios. Third, _Operational Design Domains (ODDs) may be derived_ from the scenarios. Thus, the catalogue will help specify the context and boundaries of safe teleoperation and create if-then contingencies between a certain contextual factor and its adequate driving mode. Hence, the remote operation can be incorporated in a wider framework of highly automated driving that encompasses different modes of operation, e.g., relying on input from the driving automation [33] and the infrastructure [34; 35] in addition to remote operation. This multimodal, holistic approach is conceptualized within the framework of Managed Automated Driving [36]. Fourth, the catalogue will help to _identify the most safety-relevant scenarios_ for teleoperation in public transport. This will be done, for example, by conducting a study that makes experts and operators in public transportation review the scenarios and have them rate (1) the probability of a scenario's occurrence and (2) its criticality for safe remote operation. A resulting priority classification will help understand the most pressing safety-relevant scenarios, among others, and provide a pathway to address them effectively. Subsequently, they will be used to derive user requirements to further _improve the existing HMI_ of DLR's prototypical remote operation workstation. In addition, they will also help _create adaptive HMIs_ solutions that consider the remote operator's current state and adapt the interface to accommodate it. This approach is pursued within the European Union's Horizon 2020 project \"Hi-Drive\", among others, and may be suitable to defragment the transition between various operational contexts [37]. Fifth, the identified user requirements may also facilitate creating a checklist for assessing the quality of a remote operator's workstation from a Human Factors perspective.