The impact of rhythm-based visual reference system in long highway tunnels

As typical weak visual reference systems, highway tunnels have low illumination, monotonous environment and few references, which may reduce drivers' speed perception ability and thus easily cause over- speeding and rear-end collision accidents. This study performed psychophysical experiments to assess the effect of interior visual environment on the driving safety of drivers by using the 3ds Max software, driving simulator, and E-prime software. A rhythm-based marking system was proposed to improve the visual environment of tunnels by arranging rhythm curves on side walls and note symbols on pavements, as well as multi-frequency markings (high, medium and low frequency). The accuracy rate of speed judgment and reaction time of drivers were analyzed by statistical methods and the logistics curve fitting method. The results showed that: (a) single-color rhythm markings enhanced the accuracy ratio of speed judgment by 3.33-11.66%, while multi-color rhythm markings increase this parameter by 3.33-25%. The accuracy ratio was increased by 18.33% for the second change of color in multi-color rhythm markings (t = 72 s); (b) for common highway tunnels, the reaction time of drivers showed a significant association with the driving duration in the tunnel. For tunnels with improved visual environment by rhythm markings, no significant relationship between the reaction time and driving time was noted, with drivers' fatigue effectively released; and (c) the driver reaction time depended on both the visual environment and driving duration. Rhythm markings in tunnels could effectively reduce driver reaction time. Multi-color markings had better effects than monochrome ones.