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Publication Number: FHWA-HRT-04-145
Date: December 2005

Enhanced Night Visibility Series, Volume XIV: Phase III—Study 2: Comparison of Near Infrared, Far Infrared, and Halogen Headlamps on Object Detection in Nighttime Rain

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APPENDIX G—VES CHARACTERISTICS

HID 1—HIGH/NARROW (HIGHER INTENSITY WITH NARROW BEAM PATTERN)

This system uses a complex multireflector lens to focus the beam pattern created by the HID light source. The intensity of this beam is relatively low compared to other recent headlamp designs. This means that when compared to other headlamps using isocandela diagrams, this HID design puts out lower levels of light at specific points on the road. In addition to a bright light source, the beam pattern on this particular headlamp is quite narrow, meaning that much of the available light is directed more toward the center of the roadway and not as much to the periphery or the side of the roadway.

Photo. Front view of HID 1 headlamp (high/narrow). Click here for more detail.

Figure 22. Photo. Front view of HID 1 headlamp (high/narrow).

HID 2—HIGH/WIDE (HIGHER INTENSITY WITH WIDE BEAM PATTERN)

This system also makes use of a complex multireflector lens to focus the beam pattern created by the HID light source. The intensity of this beam is relatively high when compared to other recent headlamp designs. The beam pattern on this particular headlamp is considered to be fairly wide. A wide beam pattern not only directs light in the center of the roadway, but it also directs a considerable amount of light to the periphery or the side of the roadway.

Photo. Front view of HID 2 headlamp (high/wide). Click here for more detail.

Figure 23. Photo. Front view of HID 2 headlamp (high/wide).

HID 3—MEDIUM/MEDIUM (MEDIUM BEAM INTENSITY WITH MEDIUM BEAM PATTERN)

As with all the other VESs, this system focuses its light output with a multireflector lens. The intensity of this headlamp compared to the others is in the middle range. The beam width is also average compared to the other designs.

Photo. Front view of HID 3 headlamp (medium/medium). Click here for more detail.

Figure 24. Photo. Front view of HID 3 headlamp (medium/medium).

HID 4—LOW/WIDE (LOW BEAM INTENSITY WITH WIDE BEAM PATTERN)

This system again makes use of a complex multireflector lens to focus the beam pattern created by the HID light source. The intensity of this beam is relatively high when compared to other headlamps according to the different isocandela diagrams. The pattern of the beam of this headlamp is wider than most of the others.

Photo. Front view of HID 4 headlamp (low/wide). Click here for more detail.

Figure 25. Photo. Front view of HID 4 headlamp (low/wide).

HALOGEN—LOW/NARROW (LOW BEAM INTENSITY WITH NARROW BEAM PATTERN)

This conventional headlamp has lower intensity characteristics relative to average halogen beams. The width of this beam is fairly narrow, similar to other halogens.

Photo. Front view of halogen headlamp (low/narrow). Click here for more detail.

Figure 26. Photo. Front view of halogen headlamp (low/narrow).

 

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