Evaluation of driver stress in a motor-vehicle driving simulator using a biochemical marker.

The purpose of this study was to evaluate salivary amylase activity (sAMY) as an indicator of the acute psychological effects of driving. The influence of the operation of a device not directly associated with driving was also estimated using a car navigation system. The psychological effects of driving were examined using sAMY analysis, oculomotor angle and subjective evaluation with a questionnaire, and the methods were compared. The change in sAMY over time was analysed before and during driving. The results indicate that the psychological effect of driving-induced stress, a condition that cannot be easily detected or recognized by a subjective evaluation, is quickly quantified using sAMY. Moreover, the results suggest that the operation of a non-driving-related device may also reduce the driver's capacity to concentrate on driving.