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Publication Number: FHWA-HRT-04-148
Date: December 2005

Enhanced Night Visibility Series, Volume XVII: Phases II and III—Characterization of Experimental Vision Enhancement Systems

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CHAPTER 4—CHARACTERIZATION RESULTS

The results have been subdivided into visible and ultraviolet systems. The individual VESs are shown within each of these groups. Images of the VES housings are also provided where available.

VISIBLE SYSTEMS

Halogen

Halogen headlamp bulbs generate visible light by passing electric current through a high-resistance tungsten filament. The filament is surrounded by halogen gas, allowing for higher operating temperature and longer filament life. Much of the energy output of a halogen bulb is in the infrared band of the electromagnetic spectrum. The visible light output is yellow in color. Because the ultraviolet output of a halogen lamp is minimal, only the spectral distribution within the visible spectrum appears in figure 12. In this study, both the halogen low beam and high output halogen used this technology.

Line graph. Visible light spectral power distribution of halogen lamp ranging from 380 nm to 730 nm. Click here for more detail.

Figure 12. Line graph. Visible light spectral power distribution of halogen lamp
ranging from 380 nm to 730 nm.

HID

High intensity discharge (HID) lamps produce light by means of an electrical arc discharge maintained by passing an electrical current through an ionized gas. While there are several technologies defined as HID lamps, those used in vehicle headlamps are part of the metal halide group. The lamp contains an arc tube terminated with tungsten electrodes. The arc tube typically contains xenon gas as a starting gas. The xenon gas is relatively easy to ionize at normal ambient temperatures when a high-voltage arc is passed between the electrodes. The arc tube also contains various metal halides that vaporize as the lamp reaches operating temperature. When the vaporized metal halide approaches the high-temperature arc, it disassociates into halogen and metal atoms. The heated metal vapor radiates line spectra associated with the metal. Convection currents move the halogen and metal atoms near the cooler arc tube wall where they recombine and the cycle repeats. The correlated color temperature of the emitted light is determined by selection of the metal halides contained within the lamp. For vehicle headlamps, the majority of the radiated energy is in the visible spectrum, and the resulting light appears blue-white in color. Like the halogen headlamp, the ultraviolet output is minimal; figure 13 shows the spectral distribution of the HID headlamp only within the visible spectrum.

Line graph. Spectral power distribution of HID lamp ranging from 380 nm to 740 nm. Click here for more detail.

Figure 13. Line graph. Spectral power distribution of HID lamp ranging from 380 nm to 740 nm.

LUMINAIRE CHARACTERISTICS

This section contains descriptions of each headlamp system with up to 11 parameters. The descriptions include the lamp technology (halogen, HID, UV–A, or hybrid UV–A) and beam type (low beam or high beam) of the headlamp system. The ENV abbreviation convention for each VES and a list of the ENV volumes in which it appears are included. The lamp type is the Federal Motor Vehicle Safety Standards (FMVSS) headlamp designation if a replaceable lamp is specified. The alignment type is listed according to the FMVSS 108 designation marking on the headlamp lens. The optical position for each VES is provided in table 2 through table 24. The optical center height is measured vertically from the ground plane. The distance between the optical centers of headlamp pairs is measured horizontally across the front of the vehicle or the rack. The mounting type includes three headlamp mounting methods. The original equipment manufacturer (OEM) mount, pictured in figure 14, specifies a stock mounting location and stock hardware. The rack mount, pictured in figure 15, specifies mounting on an auxiliary headlamp rack attached to the front of a vehicle. The glare rack mount, pictured in figure 16, specifies mounting on a glare rack used in studies where the experiment required oncoming headlamp glare. Relevant pictures, which include front, side, plan, and rear views of the headlamp system, are provided where available. A graph of the luminous intensity for each headlamp system is also provided. The maximum luminous intensity of the headlamp beam in candela (cd) is listed, as well as its location in degrees horizontal and degrees vertical.

Photo. Example of an OEM mount. Click here for more detail.

Figure 14. Photo. Example of an OEM mount.


Photo. Rack mount. Click here for more detail.

Figure 15. Photo. Rack mount.


Photo. Glare rack mount. Click here for more detail.

Figure 16. Photo. Glare rack mount.

Phase II Headlamp Systems

The Phase II headlamp systems appear in ENV Volumes III through VIII.

Halogen Low Beam

Table 1. Halogen low beam description.
Model description Halogen low beam
Lamp type HB5 halogen
ENV abbreviation HLB
In ENV volumes III, IV, V, VI, VII, VIII, XIII, XIV, XV
Alignment type Non-VOA mechanical aiming pads
Max beam candlepower 23,421 cd
Maximum beam location 1, −2


Table 2. Halogen low beam optical center position.
Mounting Type VES Optical Center Height (inches) VES Optical Center to Optical Center Distance (inches)
OEM mount 32.25 42.50
Rack mount 31.38 48.00
Glare rack mount 31.75 46.00


Photo. Halogen low beam front view. Click here for more detail.

Figure 17. Photo. Halogen low beam front view.


Graph. Halogen low beam isocandela plot (right headlamp). Click here for more detail.

Figure 18. Graph. Halogen low beam isocandela plot (right headlamp).

Halogen Low Beam Low Profile

Table 3. Halogen low beam low profile description.
Model description Halogen low beam
Lamp type Halogen
ENV abbreviation HLB–LP
In ENV volumes III, IV, VI, VII, VIII
Alignment type VOL (mechanical aiming methods used for this headlamp type)
Max beam candlepower 26,794 cd
Maximum beam location 2 ,−1


Table 4. Halogen low beam low profile optical center position.
Mounting Type VES Optical Center Height (inches) VES Optical Center to Optical Center Distance (inches)
OEM mount 22.63 50.50


Photo. Halogen low beam low profile front view. Click here for more detail.

Figure 19. Photo. Halogen low beam low profile front view.


Graph. Halogen low beam low profile isocandela plot (right headlamp). Click here for more detail.

Figure 20. Graph. Halogen low beam low profile isocandela plot (right headlamp).

Halogen High Beam

Table 5. Halogen high beam description.
Model description High beam
Lamp type Halogen
ENV abbreviation HHB
In ENV volumes III, IV, VII, VIII
Alignment type VOL (mechanical aiming methods used for this lamp type; aligned in same housing as the HOH below)
Max beam candlepower 36,581 cd
Maximum beam location 0, 0


Table 6. Halogen high beam optical center position.
Mounting Type VES Optical Center Height (inches) VES Optical Center to Optical Center Distance (inches)
Rack mount 35.50 56.00


Graph. Halogen high beam isocandela plot (right headlamp). Click here for more detail.

Figure 21. Graph. Halogen high beam isocandela plot (right headlamp).

High Output Halogen Low Beam

Table 7. High output halogen low beam description.
Model Description High output halogen low beam (Note: This was a prototype replacement bulb of higher output used in the OEM housing; see figure 19)
Lamp type Halogen
ENV abbreviation HOH
In ENV volumes III, IV, VII, VIII
Alignment type VOL (mechanical aiming methods used for this lamp type)
Max beam candlepower 22,752 cd
Maximum beam location −1, −2


Table 8. High output halogen low beam optical center position.
Mounting Type VES Optical Center Height (inches) VES Optical Center to Optical Center Distance (inches)
Rack mount 35.50 56.00


Graph. High output halogen low beam isocandela plot (right headlamp). Click here for more detail.

Figure 22. Graph. High output halogen low beam isocandela plot (right headlamp).

High Intensity Discharge Low Beam

Table 9. High intensity discharge low beam description.
Model description High intensity discharge low beam
Lamp type High intensity discharge
ENV abbreviation HID (HID 4 in Phase III)
In ENV volumes III, IV, V, VI, VII, VIII, XV
Alignment type VOL
Max beam candlepower 42,525 cd
Maximum beam location 1, 0


Table 10. High intensity discharge low beam optical center position.
Mounting Type VES Optical Center Height (inches) VES Optical Center to Optical Center Distance (inches)
Rack mount 34.75 42.00
Glare rack mount 36.00 44.25


Photo. High intensity discharge front view. Click here for more detail.

Figure 23. Photo. High intensity discharge front view.


Photo. High intensity discharge side view. Click here for more detail.

Figure 24. Photo. High intensity discharge side view.


Photo. High intensity discharge plan view. Click here for more detail.

Figure 25. Photo. High intensity discharge plan view.


Photo. High intensity discharge rear view. Click here for more detail.

Figure 26. Photo. High intensity discharge rear view.


Graph. High intensity discharge low beam isocandela plot (right headlamp). Click here for more detail.

Figure 27. Graph. High intensity discharge low beam isocandela plot (right headlamp).

Phase III Headlamp Systems

Phase III headlamp systems appear in ENV Volumes XIII through XVI. The headlamps used exclusively for the Phase III studies (ENV Volumes XIII, XIV, and XV) are highlighted below. In addition to these headlamps, the HLB and the HID from Phase II were used. The HID from Phase II was designated HID 4 in Phase III.

Companion Headlamp to Near Infrared 2 (NIR 2) and Far Infrared (FIR)

Table 11. Companion headlamp to NIR 2 and FIR description.
Model description Companion headlamp to NIR 2 and FIR
Lamp type Halogen
ENV abbreviation Used in conjunction with NIR 2 and FIR
In ENV volumes XIII, XIV
Alignment type VOL
Max beam candlepower 29,944 cd
Maximum beam location 2 ,−2


Table 12. Companion headlamp to NIR 2 and FIR optical center position.
Mounting Type VES Optical Center Height (inches) VES Optical Center to Optical Center Distance (inches)
Rack mount 33.00 44.25
OEM mount 37.00 58.50


Graph. Companion headlamp to NIR 2 and FIR isocandela plot (right headlamp). Click here for more detail.

Figure 28. Graph. Companion headlamp to NIR 2 and FIR isocandela plot (right headlamp).

Companion Headlamp to Near Infrared 1 (NIR 1)

Table 13. Companion headlamp to NIR 1 description.
Model description Companion headlamp to NIR 1
Lamp type Halogen
ENV abbreviation Used in conjunction with NIR 1
In ENV volumes XIII, XIV
Alignment type VOR
Max beam candlepower 21,847 cd
Maximum beam location 2, −1


Table 14. Companion headlamp to NIR 1 optical center position.
Mounting Type VES Optical Center Height (inches) VES Optical Center to Optical Center Distance (inches)
Rack mount 33.00 48.25
OEM mount 36.50 57.25


Graph. Companion headlamp to NIR 1 isocandela plot (right headlamp). Click here for more detail.

Figure 29. Graph. Companion headlamp to NIR 1 isocandela plot (right headlamp).

High Intensity Discharge Low Beam 1 (HID 1)

Table 15. High intensity discharge low beam 1 description.
Model description High intensity discharge low beam
Lamp type High intensity discharge
ENV abbreviation HID 1
In ENV volumes XIII, XIV, XV
Alignment type VOL
Max beam candlepower 17,453 cd
Maximum beam location 5, −1


Table 16. High intensity discharge low beam 1 optical center position.
Mounting Type VES Optical Center Height (inches) VES Optical Center to Optical Center Distance (inches)
Rack mount 32.75 45.00
Glare rack mount 34.50 46.00


Photo. High intensity discharge 1 front view. Click here for more detail.

Figure 30. Photo. High intensity discharge 1 front view.


Photo. High intensity discharge 1 side view. Click here for more detail.

Figure 31. Photo. High intensity discharge 1 side view.


Photo. High intensity discharge 1 plan view. Click here for more detail.

Figure 32. Photo. High intensity discharge 1 plan view.


Photo. High intensity discharge 1 rear view. Click here for more detail.

Figure 33. Photo. High intensity discharge 1 rear view.


Graph. High intensity discharge low beam 1 isocandela plot (right headlamp). Click here for more detail.

Figure 34. Graph. High intensity discharge low beam 1 isocandela plot (right headlamp).

High Intensity Discharge Low Beam 2 (HID 2)

Table 17. High intensity discharge low beam 2 description.
Model description High intensity discharge low beam
Lamp type High intensity discharge
ENV abbreviation HID 2
In ENV volumes XIII, XIV, XV
Alignment type VOR
Max beam candlepower 32,472 cd
Maximum beam location 0, −3


Table 18. High intensity discharge low beam 2 optical center position.
Mounting Type VES Optical Center Height (inches) VES Optical Center to Optical Center Distance (inches)
Rack mount 33.00 48.25
OEM mount 36.50 57.25


Photo. High intensity discharge 2 front view. Click here for more detail.

Figure 35. Photo. High intensity discharge 2 front view.


Photo. High intensity discharge 2 side view. Click here for more detail.

Figure 36. Photo. High intensity discharge 2 side view.


Photo. High intensity discharge 2 plan view. Click here for more detail.

Figure 37. Photo. High intensity discharge 2 plan view.


Photo. High intensity discharge 2 rear view. Click here for more detail.

Figure 38. Photo. High intensity discharge 2 rear view.


Graph. High intensity discharge low beam 2 isocandela plot (right headlamp). Click here for more detail.

Figure 39. Graph. High intensity discharge low beam 2 isocandela plot (right headlamp).

High Intensity Discharge Low Beam 3 (HID 3)

Table 19. High intensity discharge low beam 3 description.
Model description High intensity discharge low beam
Lamp type High intensity discharge
ENV abbreviation HID 3
In ENV volumes XV
Alignment type VOL
Max beam candlepower 22,895
Maximum beam location 0, −2


Table 20. High intensity discharge low beam 3 optical center position.
Mounting Type VES Optical Center Height (inches) VES Optical Center to Optical Center Distance (inches)
Glare rack mount 34.25 44.50


Photo. High intensity discharge 3 front view. Click here for more detail.

Figure 40. Photo. High intensity discharge 3 front view.


Photo. High intensity discharge 3 side view. Click here for more detail.

Figure 41. Photo. High intensity discharge 3 side view.


Photo. High intensity discharge 3 plan view. Click here for more detail.

Figure 42. Photo. High intensity discharge 3 plan view.


Photo. High intensity discharge 3 rear view. Click here for more detail.

Figure 43. Photo. High intensity discharge 3 rear view.


Graph. High intensity discharge low beam 3 isocandela plot (right headlamp). Click here for more detail.

Figure 44. Graph. High intensity discharge low beam 3 isocandela plot (right headlamp).


UV–A SYSTEMS FROM PHASE II STUDIES

UV–A systems appear in ENV Volumes III through X.

Sources

Two sources were used to generate the ultraviolet radiation used in the Phase II investigations. These included a prototype hybrid visible light/UV–A light source and a UV–A-only source that had been used previously on Norwegian snowplows. The lamp characteristics are shown in figure 45 and figure 46.

UV–A

Line graph. Spectral power distribution of the UV–A source. Click here for more detail.

Figure 45. Line graph. Spectral power distribution of the UV–A source.

Hybrid UV–A

Line graph. Spectral power distribution of the hybrid UV–A source. Click here for more detail.

Figure 46. Line graph. Spectral power distribution of the hybrid UV–A source.

Luminaire Characteristics

Hybrid UV–A

Table 21. Hybrid UV–A description.
Lamp type Hybrid UV–A
ENV abbreviation Hybrid UV–A
In ENV volumes III, IV, V, VI, VII, VIII
Max beam radiance 115 W
Maximum angular location 0, 0


Table 22. Hybrid UV–A optical center position.
Mounting Type VES Optical Center Height (inches) VES Optical Center to Optical Center Distance (inches)
Rack mount 29.50 25.25


Photo. Hybrid UV–A front view. Click here for more detail.

Figure 47. Photo. Hybrid UV–A front view.


Photo. Hybrid UV–A side view. Click here for more detail.

Figure 48. Photo. Hybrid UV–A side view.


Photo. Hybrid UV–A plan view. Click here for more detail.

Figure 49. Photo. Hybrid UV–A plan view.


Photo. Hybrid UV–A rear view. Click here for more detail.

Figure 50. Photo. Hybrid UV–A rear view.

Radiant Intensity

Graph. Hybrid UV–A radiant intensity. Click here for more detail.

Figure 51. Graph. Hybrid UV–A radiant intensity.


Graph. Hybrid UV–A isoWatt plot of radiant intensity. Click here for more detail.

Figure 52. Graph. Hybrid UV–A isoWatt plot of radiant intensity.

UV–A

Table 23. UV–A description.
Lamp type UV–A
ENV abbreviation three UV–A and five UV–A (see figure 53)
In ENV volumes III, IV, V, VI, VII, VIII
Max beam candlepower 201 W
Maximum beam location 0, 0


Photo. UV-A lamps on the rack mount. Click here for more detail.
Figure 53. Photo. UV-A lamps on the rack mount.


Table 24. UV–A optical center position.
Mounting Type VES Optical Center Height (inches) VES Optical Center to Optical Center Distance (outermost lamps) (inches)
Rack mount (upper row) 33.75 19.00
Rack mount (lower row) 23.00 42.00


Photo. UV–A front view. Click here for more detail.

Figure 54. Photo. UV–A front view.


Photo. UV–A side view. Click here for more detail.

Figure 55. Photo. UV–A side view.


Photo. UV–A top view. Click here for more detail.

Figure 56. Photo. UV–A top view.

Radiant Intensity

Graph. UV–A radiant intensity. Click here for more detail.

Figure 57. Graph. UV–A radiant intensity.


Graph. UV–A isoWatt plot of radiant intensity. Click here for more detail.

Figure 58. Graph. UV–A isoWatt plot of radiant intensity.

 

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