Non-Driving-Related Tasks Influencing Drivers' Takeover Time: A Meta-Analysis

Before the era of fully automated vehicles, human is consistently an indispensable part of the driving system. Various studies have investigated drivers' cooperation with the vehicle under different conditions. In this article, we analyzed how non-driving-related tasks (NDRT) influence takeover time (TOT) by conducting a meta-analysis on 37 related papers. NDRTs were transcoded into combinations of five basic dimensions to unify and demonstrate their effects on drivers. In order to interpret experimental data comprehensively, we implemented three methods. A synthetical analysis was conducted to compare the effect size between each study and subgroup. Studies with eligible control groups have been examined by the two-group analysis, followed by moderator analysis on seven variables. The results from the two-group analysis showed that both visual-mental-motoric and visual-mental tasks have significant negative effects on the takeover time and the previous type had a larger effect than the latter one. Moreover, the subgroup comparison and meta-regression in the meta-analysis part revealed the correlation between moderators and the effect size, in which the Driving Experience and the Automation Level affected the relation between NDRT and TOT. The findings of this paper can contribute to the improvement and new directions for further scientific research and engineering design.