Repeated usage of a motorway automated driving function: Automation level and behavioural adaption

The user’s perspective on highly automated driving systems is mostly studied during first contact/single usage. However, with repeated usage, acceptance and usage of automated driving systems might change. For advanced driving assistance systems, change with growing system usage is studied as behavioural adaptation. This concept of behavioural adaptation is applied to highly automated driving systems. In a driving simulator study, N = 61 drivers used an automated driving system for motorways during six experimental sessions. The drivers were free to activate / deactivate the function as they liked and to spend driving time on self-chosen side tasks. Automation level was varied as a between-subject factor (L3 vs. L4). Results show a more positive evaluation of the L4 system and behavioural adaptation for both levels over the course of the six sessions. For most aspects, behavioural adaptation is independent of system level (e.g., for system evaluation, distribution of attention). Only for drivers’ reaction to requests to intervene, a strong impact of system level on the occurrence behavioural adaption can be found. The results are discussed with regard to the theory of behavioural adaptation.