Comparison of Eye Fixations of Operators of Motorcycles and Automobiles

The eye fixations were measured of two motorcyclists who drove a motorcycle and later an automobile on two-lane rural roads at about 45 mph, in daytime. The effects of road edge delineation, road geometry, oncoming vehicles, and whether the drivers were controlling a motorcycle or an automobile were evaluated in terms of the manner in which the drivers used their eyes to obtain visual information. The results indicated that most of the drivers' attention was directed within 5° of the forward line of sight, but on curves, the drivers' eye fixations shifted in the direction of the curve. When an oncoming vehicle appeared, the drivers spent a substantial proportion of the viewing time looking at it periodically. The mean duration of glances were longer for these drivers when operating a motorcycle than an automobile. When operating the motorcycle there were relatively more glances made closer to the vehicle than when driving the car, suggesting that motorcyclists are more concerned with irregularities, composition and frictional characteristics of the pavement surface. The motorcycle riders also tended to view along the right side of the lane more than when driving the car. Comparisons made between the eye fixations of these motorcyclists when driving an automobile and those of other drivers of an automobile indicated considerable agreement, except that the motorcyclists attended more to oncoming vehicles.

The results of the study are used to infer the type of distribution of illumination required from motorcycle headlamps for night driving. The beam pattern of motorcycle headlamps should be somewhat different than that provided automobile drivers, particularly in that good foreground illumination is required for visibility of the surface characteristics of the pavement. The beam should also emphasize the right edge of the road.