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Abstract

The "moth effect" represents the tendency drivers show to steer in the direction of their fixation, often at night, toward vehicles parked on the roadside. It has been hypothesized that this phenomenon is responsible for a high number of vehicular accidents. Here, this issue is addressed with regard to the nature of the environment and the object of fixation. Prior work was based on a textured, but empty, visual landscape, and a fixation point at one particular location on the viewing screen. Building on this, two experiments were carried out in a driving simulator. Participants were instructed to steer down the center of a straight road, while maintaining fixation, which was controlled at -15, 0, or +15 degrees from center screen. In the first experiment, the richness of the environment was manipulated with the addition of numerous trees on the roadside, thus potentially providing the driver with increased optical flow, depth ordering, and velocity information. In the second experiment, the fixation point was changed from a location in screen coordinates, resembling gaze at an object in the interior of a car (e.g. a spot on the windshield), to a location in the environment. Participants thus fixated an object which was located in the car‘s exterior and drew nearer over the course of a trial. The dependent measure of interest was lateral position on the road. The results confirmed previous findings that drivers exhibit a systematic tendency to steer towards their looking direction (p < 0.05), independent of whether the target of observation was planted in the car‘s interior or exterior. However, we found that the addition of trees to the environment resulted in an attenuation of the "moth effect" (p < 0.05), indicating a compensatory role of a rich visual environment. Currently, we are investigating whether this result may alternatively be explained by a different gaze behavior or reduced fixation time on the target in crowded environments. The present data and eye-movement analyses will be discussed in terms of environmental conditions and driver safety.