## 1 Introduction  
The expectation of the release of fully automated vehicles has increased in parallel with the trend of higher automation in the industry. In the near future, as such systems emerge in the general market, a profound evolution of mobility and the transport segment will be needed [1]. Many potential benefits of this new type of vehicle are anticipated, such as increased transport comfort and safety [2]. However, the optimization of mobility through the more efficient use of travel time has given rise to the search for new use cases, which must be analyzed. In automated driven systems, driving is no longer a core task [3], and travelling can have new side purposes. Currently, the interior design of the car is focused on the driver and the driving tasks, spaces and instruments. This same space can be used for activities other than driving. The search for new vehicle concepts, led by automobile manufacturers, is an intensive and adventurous exploration which involves the creation of designs and models to define the future car interior. Simultaneously, various studies and questionnaires have been carried out to determine the desired uses for the interior of vehicles. One of the most desired activities while travelling is to rest or sleep [4]. To allow sleep activity inside the vehicle, the interior as we know it must undergo a significant transformation. The process of designing and configuring the current car safety, ergonomic and usability systems has been a long and gradual process where the knowledge develops at the same time as the needs of society and advances in technology. The high criteria when evaluating cars has been created through an ongoing adaptation process and a slow establishment of ever-higher standards. To create systems that adapt to new use cases of high automation in the vehicular field, it is important to study, predict and forecast the new future situation. Thus, in the analysis of this upcoming scenario, it is necessary to imagine and test new interior environments, creating prototypes in a various ways, both visual and physical. The development of technical solutions for such concepts is also required. The literature includes both patents and scientific papers that explore different technical solutions. However, the real, or close-to-real, physical experience of occupants is often not used due to the complexity of building such high-fidelity prototypes. Therefore, until now, the establishment of knowledge in this field has primarily consisted of very limited user experiences and the creation of imaginary scenarios. In addition, participants in user studies and tests in the field of autonomous cars have pre-conceived, inaccurate ideas about what the future will look and feel like based on current cars and expectations [5]. In conclusion, to develop new technological advances, it is important that users are directly involved and have realistic close-to-real experiences [6,7]. In particular, the research that can be found in the literature on seats for sleeping inside cars is quite limited, primarily due to the high level of novelty of the topic. In order to address the issue of sleeping in a new autonomous vehicle environment, multidimensional research is necessary to look at the topic from different perspectives, and to find comparable examples in different fields [8]. Thus, when dealing with seats, a predominant topic in the literature has been comfort and discomfort, especially, the ergonomics of the seats used in different contexts, such as cars, trains, planes, offices, etc. Surveys have been a common method of determining comfort factors that affect the user's sleep experience. The authors of [9] focused on non-driving-related tasks and provided a list of requirements for future automated vehicle interior based on an online survey and a small-scale experiment. Regarding the seat, the study determined two related preliminary requirements: the seat should support a flat position facing the driving direction, and the seat should be wider without side supports.