What type of support should be given to an automobile driver when it is determined, via some monitoring method, that the driver's situation awareness may not be appropriate to a given traffic condition? With a driving simulator, the following three conditions were compared: (a) Warning type support in which an auditory warning is given to the driver to enhance situation awareness, (b) action type support in which an autonomous safety control action is executed to avoid an accident, and (c) the no-aid baseline condition. Although the both types of driver support are effective, the warning type support sometimes fail to assure safety, which suggests a limitation of the human locus of control assumption. Efficacy of the action type support can also be degraded due to a characteristic of human reasoning under uncertainty. This paper discusses viewpoints needed in the design of systems for supporting drivers in resource-limited situations.
