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Publication Number: FHWA-HRT-04-138
Date: December 2005

Enhanced Night Visibility Series, Volume VII: Phase II—Study 5: Evaluation of Discomfort Glare During Nighttime Driving in Clear Weather

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LIST OF ACRONYMS AND ABBREVIATIONS


General Terms

ANSI American National Standards Institute
BCD borderline between comfort and discomfort
D average discomfort reported by participants
ENV Enhanced Night Visibility
FHWA Federal Highway Administration
IESNA Illuminating Engineering Society of North America
ITS Intelligent Transportation Systems
RP–8 Recommended Practice for Roadway Lighting
SUV sport utility vehicle
UV–A ultraviolet A (wavelength 315 to 400 nanometers)
VDOT Virginia Department of Transportation
VES vision enhancement system

Vision Enhancement Systems

HLB halogen (i.e., tungsten-halogen) low beam
hybrid UV–A + HLB hybrid UV–A/visible output together with halogen low beam
three UV–A + HLB three UV–A headlamps together with halogen low beam
five UV–A + HLB five UV–A headlamps together with halogen low beam
HLB–LP halogen low beam at a lower profile
HHB halogen high beam
HOH high output halogen
HID high intensity discharge
hybrid UV–A + HID hybrid UV–A/visible output together with high intensity discharge
three UV–A + HID three UV–A headlamps together with high intensity discharge
five UV–A + HID five UV–A headlamps together with high intensity discharge

Statistical Terms

ANOVA analysis of variance
DF degrees of freedom
F value F-ratio
MS mean square
p value statistical significance
SNK Student-Newman-Keuls
SS sums of squares

Measurements

cd/m² candela per square meter
cm centimeters
fL footlamberts
fc footcandles
ft feet
km kilometers
km/h kilometers per hour
lx lux
m meters
mi miles
mi/h miles per hour
min minutes
mm millimeters
nm nanometers
W/cm² watts per square centimeter
µW/cm² microwatts per square centimeter

Schmidt-Clausen and Bindels Equation

theta symboli glare angle between observer’s line of sight and the ith source (minutes of arc)
theta symbollast glare angle between observer’s line of sight and the headlamps at last location (minutes of arc)
theta symbolmax glare angle between observer’s line of sight and the headlamps at location where maximum illumination occurs (minutes of arc)
Ei illumination directed toward the observer’s eye from the ith source (lux)
Elast last level of illumination directed toward the observer’s eye from the headlamps (lux)
Emax maximum level of illumination directed toward the observer’s eye from the headlamps (lux)
La adaptation luminance (cd/m2)
R sample correlation coefficient
W mean value on deBoer’s scale
wavg predicted discomfort based on average illumination over the 91.5-m (300-ft) segment
wlast predicted discomfort based on the last illumination experienced
wmax predicted discomfort based on maximum illumination over the 91.5-m (300-ft) segment

 

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