Passengers comfort during automated motorway lane changes: a subject study on different lane change trajectories at the Stuttgart driving simulator

This article presents the setup and results of a recent subject study at the full-scale moving Stuttgart driving simulator. The study focusses on the passenger’s comfort during automated lane changes in a high-speed two-lane motorway scenario. The scenario contains different symmetric and asymmetric lane change trajectories, bends and road surface qualities. Each asymmetric trajectory is divided into two parts with different characteristics. The subjects input their subjective impression of comfort directly after each lane change on a tablet computer. The phase in which the vehicle leaves its previous lane and the phase in which the vehicle arrives at its target lane are rated individually. This enables a detailed effect analysis for the two characteristic parts of asymmetric lane change trajectory shapes. The evaluation method is able to determine subjective differences even at small objective changes. Result analysis verifies correlations between objective criteria describing the trajectory characteristics and the subjective comfort ratings. In addition, a curvature caused bias on the subjective ratings in bends is determined. The results motivate the curvature-dependent use of asymmetric lane change trajectories to improve comfort without reducing longitudinal velocity or increase lane change duration and thus maintaining traffic efficiency in terms of required traffic interspaces to cut in. The study data is further used for the development of a passengers’ comfort metric for automated driving functions.