Exploring differences in the impact of auditory and visual demands on driver behavior

Abstract

This study compared the performance metrics of drivers who carried out visual-manipulative and auditory in-vehicle tasks while driving. Although these two different types of secondary tasks resulted in similar levels of self-reported workload, performing the visual tasks had a much greater impact on measurements of lateral control and resulted in greater compensatory behavior. While performing the auditory tasks, the overlap in drivers' processing resources was less than that of the visual task. However, competition over cognitive (or central) resources was revealed through the drivers' eye movements. A reduction in the allocation of visual attention, as observed through the concentration of gaze while performing the auditory tasks, suggests that tasks involving an increase in cognitive workload can also impact driving performance. The impact on performance can cause safety concerns as drivers' compensatory adjustments have been observed to result in slower reaction times. These findings are consistent with the Multiple Resources Theory [1] and provide some quantitative support for the theory.