Best Practices for Road Weather Management Version 2.0
Enhanced Night Visibility Series, Phase II?Study 4: Visual Performance During Nighttime Driving in Fog
Phase II?Study 4 was part of the Enhanced Night Visibility project, a larger research effort investigating drivers' visual performance during nighttime driving. Study 4 helped expand the knowledge of how current vision enhancement systems can affect detection and recognition of different types of objects during adverse weather, specifically for fog conditions. Thirty participants were involved in the study. A 6 by 3 mixed factorial design was used to investigate the effects of different types of vision enhancement systems and driver's age on detection and recognition of a pedestrian on the roadway. Subjective evaluations also were obtained for the different vision enhancement systems. The analysis based on objective and subjective results revealed that the infrared thermal imaging system is the best configuration for detecting pedestrians in fog conditions. Halogen headlamps supplemented with ultraviolet A (UV?A) was a better configuration for detecting pedestrians than the halogen and high intensity discharge (HID) headlamps alone; however, the UV?A technology does not represent a dramatic improvement over the halogen and HID headlamps used in this research.
Virginia Tech Transportation Institute, Prepared for FHWA Office of Safety Research and Development, FHWA-HRT-04-137
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