Effect on mode awareness when changing from conditionally to partially automated driving

Abstract

Future vehicles will combine different levels of capable driving automation characterized by varying responsibilities for users. This development will lead to an increase in system complexity which poses the risk of confusing the driver. Based on the theory of proactive interference, we hypothesize that the users’ mode awareness suffers especially when changing from Level 3 “Conditional Automation” to Level 2 “Partial Automation”. Consequently, a mode transition intermitted by a short phase of manual driving acts as a countermeasure for a loss of mode awareness. Assumptions were tested in a driving simulator study with 45 valid participants. Mode awareness was operationalized by the visual attention towards driving-relevant areas and a qualitative analysis of an interview. Results indicate that in partial automation, visual attention does not deteriorate due to a lack of mode awareness, but rather to the development of overreliance arising from the experience with a very reliable partially automated system.