Does shifting between conditionally and partially automated driving lead to a loss of mode awareness?

Abstract

In near future, several complex automation modes – like SAE-level 2 and 3 – may be employed in one vehicle. In order to investigate the relevance of mode awareness and mode errors in the context of vehicle automation, a study with 49 participants was conducted. In the experiment, the participants experienced two stages: one stage with alternating partially and conditionally automated driving and another stage with only partially automated driving. Mode awareness and the occurrence of mode errors were compared in the two stages in order to examine the effect of shifting between the two modes. Additionally, the influence of a cognitive-auditive and a visual-motoric non-driving-related task as well as an adapted HMI was examined. Results showed that depending on the type of the non-driving-related task shifting between partially and conditionally automated driving leads to a loss of mode awareness and results in more mode errors compared to having only one automation mode. An enhancement of mode awareness by the suggested adapted HMI could not be found.