The Influence Of Lighting Conditions On Vehicle Speed Perception And Its Visual Field Differences

Speed perception refers to the process by which individual estimates and judges the speed of moving targets through a series of visual information processing.With the increasing nighttime travel,research has found that individual perceives the speed of vehicles differently between daytime and nighttime driving environments.The incorrect perception of vehicle speed is a major risk factor for nighttime traffic accidents.Whether the estimation of vehicle speed by individual is affected by the light conditions such as day and night,what is its regular performance,whether it is regulated by other factors,and what is its possible reason will be further studied in this research.This study consists of two parts.In the first study,we try to explore the effect of lighting conditions on speed perception.Through the paired comparison based on the dual comparison method(Experiment 1)and the two-choice forced selection task(2-AFC)based on the staircase method(Experiment 2),the purpose is to explore whether there are differences in individual perception of vehicle speed under different lighting conditions(,and whether it is regulated by speed factors.In study 2,the underlying causes of the difference in speed perception under different lighting conditions was studied.In experiment 3,the driving field of view is divided into central visual field and peripheral visual field,and the speed of different lighting driving scenes with the same velocity are compared in pairs,so as to examine whether there are differences in the choices distribution made by participants in speed comparison between different lighting scenes in the central and peripheral visual field,in order to preliminarily determine that the field of view is the factor of speed perception difference under different lighting conditions.On the basis of experiment 3,experiment 4 compares in pairs the speed of driving scenes in different visual fields of view with the same speed under three lighting conditions,and then analyzes the times of choices of speed comparison in different fields of view under three lighting conditions,so as to investigate the influence of fields of view on speed perception under three lighting conditions.The main conclusions of this study are as follows:(1)The perception of vehicle speed is affected by lighting conditions.From daytime to dusk and nighttime,with the decrease of brightness,individuals gradually overestimate the speed of vehicles.(2)Speed factor plays a regulating role in the speed perception under lighting conditions.Compared with the speed perception in high-brightness driving scenes,the speed perception in low-brightness driving scenes tends to be overestimated at high speed.(3)The field of view will affect the vehicle speed perception speed.The overall performance of vehicle speed perception in different fields of view is that the vehicle speed perception in the peripheral visual field is as fast as the vehicle speed perception in the whole visual field,and is significantly faster than the vehicle speed perception in the central visual field.It can be concluded that the speed perception is affected by the field of view: full visual field = peripheral visual field > central visual field.It indicates that the peripheral visual field plays a more important role in speed perception,which is the main reason to overestimate the speed in low-brightness driving scenes.(4)Lighting conditions will affect the choice proportion of speed perception in different fields of view.Relative to the daytime,the overestimation of the central visual field velocity under low-lighting conditions is greater than that of the peripheral visual field velocity under low light conditions.It may be due to the influence of light on the sensitivity of photoreceptors in different visual fields.The sensitivity of cone cells mainly distributed in the central visual field attenuates more than that of rod cells distributed in the peripheral visual field under low-lighting condition.But overall,the speed perception in the peripheral visual field is faster than that in the central visual field in whatever lighting conditions.