Effects of Illuminance Levels on Driver Comfort: Evidence from a High-Fidelity Simulator Study

Abstract: This study examined the effects of illuminance level on physiological and perceptual responses during simulated nighttime driving. Thirty licensed drivers, 15 younger (21–45 years) and15 older (65–82 years), completed three driving trials under low, medium, and high illuminance levels calibrated within roadway standards. Heart rate (HR) and subjective comfort ratings were collected to evaluate autonomic activation and perceptual experience. Results showed that illuminance level significantly affected HR, F (3, 87) = 5.94, p = 0.001. HR increased under all lighting conditions relative to baseline, but medium illuminance-maintained values closest to baseline, indicating balanced arousal. Subjective comfort ratings also varied significantly across lighting levels, F (2, 58) = 31.84, p < 0.001, with medium illumination rated highest. Age group had no interaction effect on either measure. Convergent findings identify medium illumination as the optimal level for nighttime driving, offering the best trade-off between visibility, comfort, and physiological stability.

Keywords: Nighttime Driving, Illuminance Level, Aging, Physiological Arousal, Perceived Comfort.

DOI: 10.54941/ahfe1006965

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