Measuring Driver Adaptation to In-Vehicle Information Systems: Disassociation of Subjective and Objective Situation Awareness Measures

Abstract

This study examined a range of design parameters for an in-vehicle signing and warning system, using a low-fidelity driving simulator and a variety of driver performance measures. A series of probe questions provided an objective measure of situation awareness, and drivers' confidence ratings in these answers provided a subjective measure of situation awareness. The correspondence between the accuracy of the answers to the probe questions and subjective confidence in the answers to the probe questions provides a measure of meta-situation awareness. Meta-situation awareness is a necessary condition for the validity of any subjective measure of situation awareness. Analysis of subjective and objective measures of situation awareness showed that they were both sensitive to design parameters, but that they responded in different ways. In addition, they were poorly calibrated and were only slightly correlated. This indicates a poor level of meta-situation awareness. Poor meta-situation awareness argues for great caution in using subjective measures of situation awareness. The results also suggest that meta-situation awareness may be a useful concept in explaining human performance.