In this research, cardiac, performance, and visual demand measures of driver workload were obtained from 15 male university students who drove a simulated course multiple times at a fixed speed of 72.4 km/hr. The course contained curves of 3 different radii (582, 291, and 194 m) and was driven with and without visual occlusion of the road scene to manipulate driver workload. Visual occlusion of the road scene significantly reduced driving performance, but did not affect cardiac measures. Driving performance significantly deteriorated and visual demand significantly increased as curve radius decreased. The cardiac measures were differentially affected by curve radius, indicating different modes of autonomic control for the 291-m curve as compared to the 582- and 194-m curves. Patterns of dissociation across the cardiac, performance, and visual demand measures were interpreted as being capable of isolating the perceptual demands of driving from the central and motor processing demands.
Abstract