| 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 |
