Effects of non-driving-related tasks on takeover performance in different takeover situations in conditionally automated driving

Conditionally automated driving (SAE Level 3) relinquishes driver from monitoring the driving task and the traffic environment, permitting the driver to perform non-driving-related tasks (NDRT). Nevertheless, the driver must be available as a backup option. With this in mind, the current study aims at investigating the effect of the type of NDRT and takeover situations on driver performance. The NDRTs used were writing emails and watching videos, while the takeover situations tested were avoiding an obstacle on one's lane and missing lane markings. Forty-four participants took part in a study carried in a dynamic simulator at PSA Peugeot Citroen Technical Center. Results showed that an effect of takeover situation on takeover time, with shorter times associated with obstacle avoidance, regardless of the type of NDRT. Measures of driver performance in the obstacle avoidance situation did not differ among manual and automated driving conditions, except for minimum time to collision. In the missing lane conditions, an effect of driving mode was observed on lateral and longitudinal control, as well as minimum time headway, regardless of the type of NDRT was observed. Our results suggest that the criticality of the situation had a distinct effect on takeover time and mental workload, while NDRT did not have a clear role. Furthermore, in line with previous research, drives' need for control stabilization beyond takeover was documented. (C) 2019 Published by Elsevier Ltd.