Donald E. Cleveland and Charles J. Keese, "Intersections at Night," Traffic Quarterly, Volume XV, Number 3, July, 1961




There has been relatively little research on driver tension related to the level of illumination.... The galvanic skin reflex (GSR), or change in electrical skin resistance, has been much studied since 1888. Feré had discovered then that a galvanometer, fed by a weak current and connected in series with a subject with electrodes attached to the forearosm, deflected quickly when the subject was stimulated by the sight of colored glass, the sound of a struck tuning fork, or by an odor. The response can be initiated by unexpected stimuli that may be startling or tension inducing. The GSR appears as a decrease in resistance with a magnitude proportional to the intensite of the inducing stimuli. A GSR occurs when conation or the act of striving is experienced; it is a sensitive indicator of mental functions and is associated with the subject's conscious experiences. It is particularly sensitive to sensory and ideational stimuli, especially those associated with alertness, attention, apprehension, and arousal....

Figure 4 presents the number of tension responses recorded on the various paths through the intersection with the lights on and off. The addition of illumination provides no tension-response relief for movements 4 and 5. The location of the luminaires is such that movement 5 receives little additional light, and the high-speed diverging movement, number 4, is believed by a number of those who observed it in operation to be inadequately illuminated.