Electrodermal response, heart rate, and muscular activity were measured for 60 subjects driving a rural test route. Brake pressure and steering wheel angle were also recorded, and traffic events encountered were categorized by the experimenter using a keyboard. A total of 7 million data points were obtained and stored on a digital tape recorder in the test vehicle. Traffic event categories were then rank ordered according to magnitude of response. For electrodermal response and brake pressure, a spearman rank correlation coefficient of .95 was obtained. Time sequence analyses of the drivers' physiological responses and motor activity show that electrodermal responses are induced by the mental effort of the driving task rather than thephysical effort necessary to manoeuvre the vehicle. The results have ergonomic implications for highway design.(A)
Abstract