Head-Up Displays in Urban Partially Automated Driving: Effects of Using Augmented Reality *

In partially automated driving the vehicle takes over lateral and longitudinal control in specific situations. The driver acts as a supervisor of the driving automation system, and must be able to intervene immediately if functional limits are reached. Therefore, the driver needs to be aware of actual and planned system actions. Due to the complexity of the urban traffic environment when compared with that of well-structured highways, optimized driver-vehicle interaction is essential. The choice of a suitable display seems to be a key factor, since most information is perceived visually while driving. A promising method for supporting the driver is an Augmented Reality Head-Up Display (ARHUD). An ARHUD visualizes information at its actual location in the primary field of view in contrast to a conventional Head-Up Display (HUD). To investigate the potential of an ARHUD in comparison with a HUD, 30 participants took part in a driving simulator study experiencing a partially automated journey supported by an ARHUD or a HUD in a within-subjects design. Results show significant differences in gaze behavior for the two display concepts. The ARHUD results significantly in higher trust and lower subjective workload compared to the HUD. However, no significant differences exist in usability.