Mental Workload as a Function of Road Type and Visibility: Comparison of Neurophysiological, Behavioral, and Subjective Indices

Abstract

Advanced in-vehicle technologies (IVTs) are rapidly being introduced. Methods of assessing the mental workload required by the driving situation are imperative to the safe implementation of these advanced systems. The current investigation compared the sensitivity of an array of assessment techniques to changes in simulated driving task demand. P300 amplitude was sensitive to increased driving task demand due to reduced visibility (presence of fog) but was not sensitive to changes in road type (urban versus freeway). Conversely, RT and accuracy to a secondary task were sensitive to changes in road type but were not sensitive to the visibility manipulation. Subjective workload ratings were not sensitive to either manipulation. Results are discussed in terms of their implications for assessing the impact of environmental factors on the mental workload demands of the driving task and for the design and implementation of adaptive driver interfaces.