Manual takeover after highly automated driving: Influence of budget time and Lane Change Assist on takeover performance

The current study aimed at investigating the effectiveness of additional assistance system to support driver performance during a takeover request in a conditionally automated vehicle, that is, Level 3 of SAE taxonomy. Seventy drivers participated in the simulator carried on a driving simulator (62 drivers retained). The takeover request issued due to another vehicle blocking the way obliged the participant to take over and change lane. Two versions of a Lane Change Assist (LCA) were tested across two groups with short (4 sec) and long (8 sec) time budget for a takeover. We observed that when provided longer takeover time budget, higher number of drivers completed the lane change maneuver successfully, adopted different takeover strategy, and had fewer accidents. We did not observe an effect of the presence or the type of LCA on takeover performance. However, a comparison of incident-free takeovers with those with a lateral collision revealed that the presence of LCA was associated with higher number of incident-free takeovers in the 8-sec group. Overall, drivers could benefit from additional assistance systems during takeover, especially when they are provided enough time to process information and act upon it.