This study explores the research hypothesis that perceptual learning could occur with visual exposure to a repeating alternation between 2-D vs 3-D video images of terrain hazards typically encountered in off-road driving of ground vehicles. In individual sessions, each of the nine untrained test subjects was shown 20 off-road terrain-hazard scenes on a color video display. Each hazard was shown first in 2-D mode, then in 3-D mode, and then with 2-D/3-D mode alternating on the video screen. In 2-D mode, only one of the 20 terrain hazards was perceived by two of the nine subjects, whereas all 20 terrain hazards were immediately perceived by all subjects when the display switched over to 3-D mode. A post-test presented mirror-image versions of the same 20 hazards in 2-D only, to determine if the previous 2-D/3- D alternation treatment improved the ability to detect terrain hazards in 2-D mode. At the end of their session, test subjects were given a questionnaire asking them to rate the degree of perceptual training resulting from 2-D/3-D alternation. All 20 subjects reported that the 2-D/3- D alternation improved their sensitivity to the monocular cues of terrain hazards presented on a 2-D video display. The implications that can be drawn from this preliminary study are: (1) in off-road driving by means of a conventional 2-D video display, operators will fail to perceive many significant terrain hazards; (2) however, with a 3-D video display, operators will immediately perceive most terrain hazards and will interpret terrain contours easily and accurately; (3) a more extensive experiment is indicated to formally determine the extent of the perceptual training that can be obtained by 2-D/3-D alternation.