Autonomous driving is one of the megatrends in the automotive industry. Vehicles that no longer need the driver’s attention raise the expectation among users to use their time gained efficiently, for example automated driving would allow the car to be a place to work, a place to socialize, to relax or to take a nap. The automated vehicle (AV) would be more of a living space, rather than just a mode of transportation. For the basic vehicle layout new seat configurations, with or without a seat rotation, along with new seating postures must be considered. Since up to now, the vehicle layout conception is based on a neutral driver posture, this will certainly lead to influences on the vehicle dimensions. Therefore, a geometric analysis with digital human models was conducted with regard to influences of relevant seating parameters on the space needed in a vehicle. We considered new seating postures in use cases linked to automated driving, human anthropometry, seat height (H30), backrest tilt/torso angle (A40), seat rotation angle and X-position of seat rotation axis. The analysis confirmed that most conventional vehicle bodies are too limited in space for big changes in the seat configuration, but there is potential for small angles of rotation. The results help to understand how the proportions of vehicles will change or what configurations would fit into the limited space in different vehicle types in a very early phase of vehicle design. New seating postures have been investigated in some studies in connection with non-driving related tasks, but have never been integrated holistically into the method of a user centred vehicle layout conception. Therefore, the results of the study are combined with further findings from the literature and integrated into a revised method for vehicle layout conception in the early design phase.