Quantifying effects of reverse linear perspective as a visual cue on vehicle and platoon crash risk variations in car-following using path analysis.

Road markings are prevalent in practice as perceptual countermeasures to crashes, and a great deal of them have been used for speed reduction. However, there is rare seen any equivalent measures especially for distance control. More importantly, the visual perceptual mechanism of road markings on driving behaviors and crash risk is still blur. Given this, in the present study, we comprehensively quantified the effects of reverse linear perspective (RLP) from its origin as a visual cue, produced by a kind of transverse line markings on road, and explored the effects on car-following behaviors and crash risk variations by path analyses imbedded in a structural equations model, which was approximated with naturalistic driving and traffic flow data. In the model, multiple sources of observed factors in visual perception, driver behaviors, and traffic flow characteristics, and exogenous unobserved factors of distance risk perception, speed risk perception, and platoon risk status were comprehensively structured to explain the vehicle crash risk variation and the platoon crash risk variation. The results indicate that (1) distance risk perception, speed risk perception, and platoon risk status were well explanatory and predictive to vehicle crash risk variation and platoon crash risk variation; (2) the effects of reverse linear perspective as a visual cue on driving behaviors and crash risk variations in car-following were adequately quantified by its geometrical characteristics concerning distance perception; (3) the visual cue of reverse linear perspective in addition with initial distance, stopping sight distance, and the type of leading vehicles explained 33 % of the variance in distance risk perception; the temporal frequency, initial speed, and the type of following vehicles explained 23 % of the variance in speed risk perception; distance risk perception, speed risk perception, and platoon risk status combinedly explained 25 % and 22 % of the total variance in vehicle crash risk variation and platoon crash risk variation, respectively; (4) vehicle crash risk variation and platoon crash risk variation were equivalently specified by those observed explanatory factors. The findings of this study suggest the usefulness and importance of understanding the contribution of psychological factors on crash risk, and emphasize that the road markings can be an effective and readily practical countermeasure in easing traffic safety issues.