Effect of non-driving related task and seat back angle on preferred seat parameters in highly automated vehicles

This study investigated the effects of non-driving related tasks (NDRTs) and seat back angles (SBAs) on preferred seat parameters and seating discomfort in highly automated vehicles. Using a static, reconfigurable experimental seat, 32 participants self-selected preferred seat parameters for four tasks with varying vision demands (relaxing, looking forward, working on a laptop, watching a tablet video) at three SBAs: 20°, 40° and 60°. Results show that SBA influenced all self-selected seat parameters, while task only affected those related to the headrest. Fore-aft headrest adjustability is necessary to support different NDRTs, particularly in reclined postures. Upright and moderately reclined positions were preferred for downward-looking tasks like laptop or tablet use, while more reclined positions were better suited for relaxing without visual demand. The findings also highlight the importance of suitable support for tablet use to reduce discomfort. They could be useful for seat and vehicle interior design in future automated vehicles.