Automated driving: Study on feasibility for drivers to take over vehicle control
Multitasking Has Its Limits
The introduction of highly automated and fully automated driving systems in cars will change the role of the driver in future. In certain circumstances, the driver is allowed to perform a secondary activity, but only on the condition that they take over within a matter of seconds if requested to do so by the system. However, what if there were a potentially critical situation and this request never came? A study on this topic conducted by DEKRA and Dresden University of Technology (TU Dresden) shows that humans are limited in their ability to multitask. “That is why the technical maturity of automated driving functions must meet the strictest of requirements. It is imperative that any systems that are approved do not, under any circumstances, expect the driver to suddenly take over,” said Dr. Thomas Wagner, Traffic Psychologist and Head of DEKRA’s Assessment Centers for Driving Suitability.
- Field study with four takeover scenarios at the DEKRA Lausitzring
- Takeover sometimes very difficult even without a secondary activity
- DEKRA and TU Dresden state there is a research gap in "silent alarms"
The researchers recruited a pool of almost 90 people to take part in the field study from among students at TU Dresden and the Senftenberg University of Applied Sciences, and via public networks, of which 36 ultimately took part in the test drives. The participants were not told about the real background to the study. On average, the participants had been in possession of a class B driver’s license for around eight years, were between 19 and 48 years of age, and had gained approximately 9,400 kilometers of driving experience per year.
The experimenter triggered one false alarm and three silent alarms during each test drive. In the former, the vehicle sounded a takeover warning, even though the situation was not actually critical. “The three silent alarms applied to driving over a stop line with a stop sign, slowly drifting over to the opposite lane, and performing a sudden evasive maneuver to avoid an erroneously detected obstacle,” said Dr. Wagner. All four takeover scenarios were triggered after the test subject had already driven around the circuit several times without encountering any unusual events.
Overall, the takeover after a false alarm proved to be relatively unproblematic. All of the test subjects – in both the experiment group who had the tablet task and the control group who did not have a secondary activity – succeeded in taking over control of the vehicle. “It was different with the silent alarm,” said DEKRA expert Dr. Wagner. “Participants in both groups had considerable difficulty in taking over control of the vehicle. However, the number of unsuccessful takeovers was around double in the group that had the secondary activity in all scenarios.”
The DEKRA experts and TU scientists think that there is a substantial research gap with respect to silent alarms: Less than ten percent of research published so far on this subject concerns “disengagement situations”, i.e., system failure due to a fault. “Even though the silent alarms issue is probably the most safety-critical aspect of highly automated driving, it is vastly underrepresented in existing research,” said Dr. Wagner. “We must discuss the issue of whether it is even possible for humans to safely perform a secondary activity while paying a minimum level of attention to the driving system and the traffic, which is what the law, for example in Germany, currently stipulates,” warned the expert.