“…Actually, the influence of visual perception on driving behaviors and collision avoidance was originally noticed by some cognitive psychologists, who verified in virtual-reality scenes that the existence of certain visual information (which was termed as "visual cues") on ground surface could lead to drivers' overestimation of speed [42,44,48,62,63], underestimation of distance [44,[64][65][66][67][68][69][70], and untimely and inadequate brake [42,43]. Inspired by those cognitive psychologists, Ding et al [14,21,24,71,72] conducted a series of studies focusing on associating, evaluating, and explaining the effects and mechanism of drivers' speed perception and distance perception on car-following behaviors and crash risk, by introducing and testing several specially designed perceptual markings with on-road experiments and observations. In addition, the inherent connection between speed/distance perception, driving behaviors, and crash risk was comprehensively accounted for by two latent variables, i.e., "speed risk perception (SRP)" and "distance risk perception (DRP)," which differentiated the risk perception originating from variations in speed and distance [14].…”