Time Required for Take-over from Automated to Manual Driving

Automation of vehicles can be expected to improve safety, comfort and efficiency, and is being developed in various countries. Introduction of automated driving can be ranked from 0 to 5 (0: no automation, 1: driver assistance, 2: partial automation, 3: conditional automation, 4: high automation, 5: full automation). Currently, feasible automation levels are considered to be levels 2 or 3, and human manual take-over from the automated system is needed when the automated system exceeds these levels. In this situation, time required for take-over is an important issue. This study focuses on describing driving simulator experimental results of time required for take-over. The experimental scenario is that the automated system finds an object ahead during automated driving on the highway, and issues a take-over request to the driver. The subject driver can be in the following driver situations: hands-on or hands-off the steering, and strong or weak distractions. In these situations, we examine two kinds of take-over time, which are 7 and 5 seconds. The results show all subjects complete take-over actions properly even if the required time is 5 seconds. In this paper, details of these results are described.