A technique to determine what features of the road and terrain the driver is responding to is presented in this study. The method involves having the driver guide the car while looking through a device containing a small aperture. By decreasing the visual field, the essential information, whatever it is, cannot be seen at once, i.e., the driver is forced to obtain this information in separate visual fixations. A continuous film record is made of the drivers field of view which is later analyzed to indicate the center of his visual aim and the content of each fixation. Visual position data were obtained on ten drivers who followed a two-lane low traffic density road, using this aperture device. The film records provided 3,305 separate fixations which were coded for position, distance from the eye, and duration. The follow conclusions were reached: (1) the essential information required by the driver is provided by the road edges and center lane marker, (2) all drivers utilized the road edges and centerline to guide the vehicle, but the manner in which this information was obtained differed from subject to subject and film records refute the notion that the driver has a fixed point of forward reference, (3) the position of fixation tended to shift in the opposite direction when going from a left to a right curve, (4) the hypothesis is presented that the persistent pattern of fixation movements forward to the limits of the road and back to the vehicle are explained by the contradictory requirements of perceptual anticipation and vehicular alignment with the road, (5) methodological problems concerning the adequacy of introspective data for determining the drivers visual input, and the stress of small aperture viewing, are discussed, and (6) the implications of these results for the placement of signs and highway markings are presented. [Paper also published as: Highway Research Record, 1966, No 122, pp 19-34, 5 FIG, 19 TAB, 9 REF]
Abstract