Effects of non-driving-related tasks on driving performance after takeover request in automated driving (Level 3): a simulator study

Drivers are more likely to engage in non-driving-related tasks (NDRTs) until a takeover request prompts them to resume vehicle control in Level 3 automated driving. The objective of the present study was to evaluate the impact of diverse categories of non-driving-related tasks on driving performance subsequent to a takeover request. The study was conducted using a truck and bus simulator. A total of 31 participants were involved in the study. Following the training, the drivers performed a driving session without any other activity, and then six different activities in three scenarios were tested. The six NDRTs examined included: working on a laptop, making a phone call, watching a video, taking an audio course, relaxation with closed eyes, and manual activity. The driving performance was evaluated using a variety of metrics, including takeover time, average speed, vehicle distance to the centre of the lane, and an assessment of situational awareness. The results indicated that all NDRTs impaired driving performance to a certain extent; however, the extent of influence differed for each type of activity. The riskiest activities identified were found to be working on a laptop, watching a video, and making a phone call, which aligns with theoretical assumptions. Statistically significant differences in takeover time and average speed were identified for relaxation, working on a laptop, performing a manual task, participating in an audio course and watching a video.