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 |
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 |
i |
glare angle between observer’s line of sight and the ith source (minutes of arc) |
last |
glare angle between observer’s line of sight and the headlamps at last location (minutes of arc) |
max |
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 |