New study measured takeover time in automated vehicles

The SAE levels for vehicle automation provide for 5 stages. Level 1 begins with driver assistance systems whereas level 5 conversely means full automation, allowing the driver to sit back and relax while the vehicle is doing the work. But it will surely take some time until autonomous driving has reached level 5. Experts assume that it will be possible until the year 2025, others believe that the technology will enter production stage even twenty years later.

However global manufacturers do not want to wait until 2025. Instead they aim to monetize level 2 – level 4, which requires a legal framework. Ideally this must happen on a global scale. Safety matters of semi-autonomous vehicles are linked with the question of how to design the transfer from autonomous mode to manual mode during the drive. Some manufacturers have already found a way to steer the autopilot. But what about the time it takes to do so? Security is defined as an accepted risk. How big should be the risk of handing over? The World Forum for Harmonization of Vehicle Regulations (WP 29) deals with questions like this, their next meeting of the UN organization is scheduled for March.

Meanwhile, researchers from the University of Southampton have been dealing with the takeover time and dared an experiment. 26 subjects of different ages (from 20 to 52 years) were put into a driving simulator. During the first run they should follow the traffic carefully, though the car drove by itself. The simulated distance was around 30 kilometers and the simulated car drove over 65 mph. Then the subjects were request to take control, which was communicated visually and acoustically. The second run proceeded with different test conditions: The subjects should read a newspaper during the drive. As a result, it took the test persons 1.5 seconds longer to take control over the vehicle. Before it took them on average 4.5 seconds to take over when not distracted. Therefore, the researchers recommend to integrate a surveillance camera in the interior of the partially and highly autonomous vehicles. This has already been announced by a large US vehicle builder.

Whereas the result of the study is not surprising, the statistical outliners of this experiments are all the more. Individuals succeeded in gaining control within two seconds, others however took it significantly longer. One person even needed about 26 seconds. At a speed of 60 mph on a motorway the driver would travel 700 meters without being able to concentrate on the traffic. The solution can be seen in an average value, but the time value should not be too short to avoid rushing the drivers and stressing them out. This could lead to unintended maneuvers like changing lanes or braking too hard. According to the scientists, the takeover time can be measured longer as long as there is no emergency. Above all, a speed reduction seems to be useful in such cases to me.

Here the question of liability arises once more. Judging by the example of the German draft law for autonomous driving, it requires the driver to intervene in emergencies because he is the one liable even during the automated drive. But the law is lacking highly relevant details – such as a definition of an adequate takeover time.

David Fluhr is journalist and owner of the digital magazine “Autonomes Fahren & Co”. He is reporting regularly about trends and technologies in the fields Autonomous Driving, HMI, Telematics and Robotics. Link to his site: http://www.autonomes-fahren.de