DRL Induced Glare An Analytical Study of the Effects of Peak Luminous Intensity.
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Transcript of DRL Induced Glare An Analytical Study of the Effects of Peak Luminous Intensity.
![Page 1: DRL Induced Glare An Analytical Study of the Effects of Peak Luminous Intensity.](https://reader031.fdocuments.in/reader031/viewer/2022013114/5519e7d0550346443e8b51f6/html5/thumbnails/1.jpg)
DRL Induced Glare
An Analytical Study of the Effectsof Peak Luminous Intensity
![Page 2: DRL Induced Glare An Analytical Study of the Effects of Peak Luminous Intensity.](https://reader031.fdocuments.in/reader031/viewer/2022013114/5519e7d0550346443e8b51f6/html5/thumbnails/2.jpg)
NHTSA Proposed RulemakingAugust 7, 1998
Federal Motor Vehicle Safety Standard 108:
Lamps, Reflective Devices and Assoc. Equip.
Proposed Rule Change:
Reduction in the maximum permitted
luminous intensity for vehicle daytime
running lights [DRLs]
![Page 3: DRL Induced Glare An Analytical Study of the Effects of Peak Luminous Intensity.](https://reader031.fdocuments.in/reader031/viewer/2022013114/5519e7d0550346443e8b51f6/html5/thumbnails/3.jpg)
Rational for Proposed Rulemaking
400+ complaints re: excessive glare
from U.S. public on file
(N.B. Virtually no complaints in Canada)
“This action is intended to provide the
public with all the conspicuity benefits of
DRL’s while reducing glare”
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U.S. DRL Intensity Specification
Current Maximum: 7000 cd
compatible with Canadian specification
compatible with high-beam headlamps
operated at half voltage
34-inch maximum mounting height
(else 3000 cd – rearview mirror glare)
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Proposed Maximum: 3000 cd (Phase I)
1500 cd (Phase II)
demonstrated “conspicuity” benefits under
high ambient daytime illumination
(based on “search conspicuity” paradigms)
minimal discomfort glare
(especially re: rearview mirrors)
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Modeling the Magnitude of Glare Effects
Disability GlareAdrian & Bhanji (1991) equation
Relative elevation of contrast threshold
Discomfort GlaredeBoer Subjective Rating Scale
Schmidt-Claussen & Bindels (1974) model
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Analytic Conditions
(4) DRL Intensities
1500, 3000, 5000, 7000 cd
(Proposed – Current NHTSA Maximum)
(5) Observation Distances
20, 40, 60, 80, 100 m
(6) Driver Light Adaptation States
1, 50, 100, 500, 1000, 5000
(Dark-to-Brightest Summer Day)
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Driver Luminance Adaptation States
Adaptation Ambient
Time of Day State Illumination
(cd/m2) (lux)
road at night 5 100
twilight / dawn 250 5000
clear winter day 500-150010,000-30,000
brilliant summer day 5000 85,000+
Luminance (cd/m2) = illumination (lux) * reflectance / p
assumption: average scene reflectance = 0.15
(asphalt road = 0.10, grass = 0.20)
![Page 9: DRL Induced Glare An Analytical Study of the Effects of Peak Luminous Intensity.](https://reader031.fdocuments.in/reader031/viewer/2022013114/5519e7d0550346443e8b51f6/html5/thumbnails/9.jpg)
Adrian & Bhanji (1991)Disability Glare Model
Lequivalent = k
2
glare
k
glare is the illumination of the glare source at the eye of the observer (lux)
= 9.05Age (in years)
66.4( )
4
1 +( )is the angle between the glare source and the observer's line-of-sight (degrees)
where:
( Equation 1 )
![Page 10: DRL Induced Glare An Analytical Study of the Effects of Peak Luminous Intensity.](https://reader031.fdocuments.in/reader031/viewer/2022013114/5519e7d0550346443e8b51f6/html5/thumbnails/10.jpg)
Influence of Veiling Luminance(Reduction of Retinal Contrast/Visibility)
Nominal Contrast = Ltarget
– Lbackground
/ Lbackground
Ltarget
+equivalent
Lbackground
L
+equivalent
L( ) +equivalent
Lbackground
L( )-Contrastglare
=
+equivalent
Lbackground
L
backgroundLL
target-
=
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Effects of Glare upon Contrast Sensitivity(Due to Veiling Luminance)
+equivalent
L
Threshold elevation =
backgroundLL
target -
backgroundL
backgroundL
backgroundLL
target-
(
(
)
)
Threshold elevation = Retinal Contrast without Glare Retinal Contrast with Glare
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1% Contrast Elevation Factor
backgroundL ( 0.01 ( ) ) / (
backgroundL
equivalentL+ )
0.01
Blackwell (1946) showed that small and mid-size objects in theroadway environment can be detected at a contrast of 1%across a broad range of photopic luminance levels.
The effect of veiling retinal luminance upon this nominaldetection threshold can be estimated as follows:
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Glare Illumination:Viewing Distance & DRL Intensity
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Disability Glare Drops Rapidlywith Increasing Luminance Adaptation
10001001010
2
4
6
8
10
12
7000
5000
3000
1000
75-year-olds20m (8.93 degrees)
Luminance Adaptation (cd/m2)
Con
tras
t T
hre
shol
d E
leva
tion
DRL Intensity
Conclusion:
DRLs can cause some “disability” at nighttimebut not betweendusk and dawn.
But…What about“discomfort” glare?
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Discomfort Glare
deBoer Subjective Rating Scale
1 Unbearable23 Disturbing45 Just Acceptable67 Satisfactory89 Just Noticable
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Schmidt-Claussen & Bindles (1974)Disability Glare Model
deBoer Discomfort
Glare Rating= 5.0 - 2 log
glare
0.003 )(1 + backgroundL
0.04
0.46
backgroundL
glare is the illumination of the glare soure at the eye of the observer (lux)
is the angle between the glare source and the observer's line-of-sight (minarc)
is the background adaptation state of the observer (cd/m2)
where:
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deBoer Discomfort GlareDRL=1500 cd; Changing Adaptation Level
10080604020001
2
3
4
5
6
7
8 1500 cd
Distance (m)
Dis
com
fort
Gla
re R
atin
g
50 cd/m2100 cd/m2
500 cd/m21000 cd/m2
5000 cd/m2
Comfort
Discomfort
Adaptation LevelDay/Clear Sky
Dusk/Dawn
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deBoer Discomfort GlareDRL=3000 cd; Changing Adaptation Level
10080604020001
2
3
4
5
6
7
8 3000 cd
Distance (m)
Dis
com
fort
Gla
re R
atin
g
50 cd/m2100 cd/m2
500 cd/m21000 cd/m2
5000 cd/m2
Comfort
Discomfort
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deBoer Discomfort GlareDRL=5000 cd; Changing Adaptation Level
10080604020001
2
3
4
5
6
7
8 5000 cd
Distance (m)
Dis
com
fort
Gla
re R
atin
g
50 cd/m2100 cd/m2
500 cd/m21000 cd/m2
5000 cd/m2
Comfort
Discomfort
![Page 20: DRL Induced Glare An Analytical Study of the Effects of Peak Luminous Intensity.](https://reader031.fdocuments.in/reader031/viewer/2022013114/5519e7d0550346443e8b51f6/html5/thumbnails/20.jpg)
deBoer Discomfort GlareDRL=7000 cd; Changing Adaptation Level
10080604020001
2
3
4
5
6
7
8 7000 cd
Distance (m)
Dis
com
fort
Gla
re R
atin
g
50 cd/m2100 cd/m2
500 cd/m21000 cd/m2
5000 cd/m2
Comfort
Discomfort
![Page 21: DRL Induced Glare An Analytical Study of the Effects of Peak Luminous Intensity.](https://reader031.fdocuments.in/reader031/viewer/2022013114/5519e7d0550346443e8b51f6/html5/thumbnails/21.jpg)
Saturn Special CaseAlternator Over voltage => 10,000 cd
10080604020001
2
3
4
5
6
7
8 10000 cd
Distance (m)
Dis
com
fort
Gla
re R
atin
g
50 cd/m2100 cd/m2
500 cd/m21000 cd/m2
5000 cd/m2
Comfort
Discomfort
![Page 22: DRL Induced Glare An Analytical Study of the Effects of Peak Luminous Intensity.](https://reader031.fdocuments.in/reader031/viewer/2022013114/5519e7d0550346443e8b51f6/html5/thumbnails/22.jpg)
DRL Discomfort Borderlines
1008060402000
Distance (m)
Dis
com
fort
Gla
re R
atin
g
50 cd/m2100 cd/m2
500 cd/m21000 cd/m2
5000 cd/m2
1500 cd
3000 cd5000 cd7000 cd
10000 cd
Adaptation State
DRL Intensity
Discomfort
Comfort
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European Glare Sensitivity?
1000010001001
2
3
4
5
6
7
8
9
UMTRI (1999)Schmidt-Claussen & Bindels (1974)
DRL Intensity (cd)
deB
oer
Dis
com
fort
Rat
ing
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DRL Intensity > 2000 cdSmall Gains in Visibility
Large Increases in Discomfort
1000010001001010.0
0.2
0.4
0.6
0.8
1.0
DRL Intensity (cd)
Vis
ibil
ity
Ben
efit