  Remotely operating vehicles utilizes the benefits of vehicle automation when
fully automated driving is not yet possible. A human operator ensures safety
and availability from afar and supports the vehicle automation when its
capabilities are exceeded. The remote operator thus fulfills the legal
requirements in Germany as a Technical Supervisor to operate highly automated
vehicles at SAE 4. To integrate the remote operator into the automated driving
system, a novel user-centered human-machine interface (HMI) for remote
assistance workplaces was developed and initially evaluated. The insights
gained in this process were incorporated into the design of a workplace
prototype for remote assistance. This prototype was now tested in the study
reported here by 34 participants meeting the professional background criteria
for the role of Technical Supervisor according to the German law by using
typical remote assistance scenarios created in a simulation environment. Even
under elevated cognitive load induced by simultaneously engaging in a secondary
task, participants were able to obtain sufficient situation awareness and
quickly resolve the scenarios. The HMI also yielded favorable usability and
acceptance ratings. The results of the study inform the iterative workplace
development and further research on the remote assistance of highly automated
vehicles.
