Non-visual Effects of Road Lighting CCT on Driver's Mood, Alertness, Fatigue and Reaction Time: A Comprehensive Neuroergonomic Evaluation Study

Good nighttime road lighting is critical for driving safety. To improve the quality of nighttime road lighting, this study used the triangulation method by fusing "EEG evaluation + subjective evaluation + behavioral evaluation" to qualitatively and quantitatively investigate the response characteristics of different correlated color temperature (CCT) (3500K, 4500K, 5500K, 6500K) on drivers' non-visual indicators (mood, alertness, fatigue and reaction time) under specific driving conditions (monotonous driving; waiting for red light and traffic jam; car-following task). The results showed that the CCT and Task interaction effect is mainly related to individual alertness and reaction time. Individual subjective emotional experience, subjective visual comfort and psychological security are more responsive to changes in CCT than individual mental fatigue and visual fatigue. The subjective and objective evaluation results demonstrated that the EEG evaluation indices used in this study could objectively reflect the response characteristics of various non-visual indicators. The findings also revealed that moderate CCT (4500K) appears to be the most beneficial to drivers in maintaining an ideal state of mind and body during nighttime driving, which is manifested as: good mood experience; it helps drivers maintain a relatively stable level of alterness and to respond quickly to external stimuli; both mental and visual fatigue were relatively low. This study extends nighttime road lighting design research from the perspective of non-visual effects by using comprehensive neuroergonomic evaluation methods, and it provides a theoretical and empirical basis for the future development of a humanized urban road lighting design evaluation system.