Should the Urgency of Visual-Tactile Takeover Requests Match the Criticality of Takeover Situations?

Highly-automated driving requires drivers to take over the control of their vehicle in any situation. In takeover situations with small time headways, a fast takeover is crucial. Here, drivers could be supported by an appropriate takeover request. This article presents a driving simulator study investigating whether less critical takeover situations and a match between the urgency of a takeover request and the criticality of the takeover situation benefits drivers regarding their takeover performance and subjective experience. Fifty-two participants experienced two takeover situations with varying time headways (small and large). A low urgent, visual-tactile takeover-request was presented to half of the participants. The other half experienced a highly urgent, visual-tactile takeover request, resulting in two conditions, in which the takeover requests matched the criticality of the takeover situation, and in two conditions, in which the takeover requests did not match. The results showed that participants generally performed better in low critical takeover situations, but they took over quicker in highly critical situations. However, a match neither shortens takeover time nor enhances subjective experience.