Visibility Performance UnderVisibility Performance Under New Lighting Technologies
Dr. Ronald B. GibbonsGroup Leader, Lighting and Infrastructure
Technologygy
Anchorage Alternative Li htiLighting
This project was the investigation of the impact of broad spectrum light sources on driver visibility.
Visibility was rated based on the detection distance of ll t t th id f th da small target on the side of the road
Luminance and Illuminance was measured in-vehicle during the experimentg p
Experimental Designp g
Variable DescriptionLighting five alternative light sources (Dimming HPS, Beta LED, Kim
Induction, Lumecon LED, Kim LED), one group of the existing condition (HPS 400W Non-Dimming)
Lighting Level High and Low (Dimmed) *Except existing conditionLighting Level High and Low (Dimmed) Except existing condition
6 different lighting systems were tested along an urban street in Anchorageurban street in Anchorage• HPS, LED, Induction
2 Dimming Levels2 Dimming Levels• Attempting to investigate adaptive lighting
Lighting Layoutsg g y
Participantsp27 Participants from the public were tested for object detection and public opinion• The participants were invited by the Anchorage
M ffi t t k t iMayors office to take part in a survey• After a briefing at the Public Library, participants were
taken to the test area in buses where they were allowed yto rate the installations
• During the subjective rating sessions, 3 participants d t d f thwere drawn at random from the group.
MethodsAfter Pickup, the Participants were then driven to the beginning of the test area and instructed on the taskEach participant was given a button to press when they were sure that they could see the target on the side of the roadthe side of the road.• Two targets were located in each test area
The button presses were recorded in the data fileThe button presses were recorded in the data file
Equipmentq pThe VTTI RLMMS was installed on a rental vehicle and used during the data collection• The measurement system utilizing GPS, a Luminance
d ill i t d h t t icamera and illuminance meters records photometric and visual information at 10 Hertz.
• The system, also measures:y ,• Spectroradiometer• Button Presses• Color Video Camera• Vertical Illuminance• Linking to Automobile J1850 interface for SpeedLinking to Automobile J1850 interface for Speed
and Throttle information
System Layouty y
Data Collection
Luminance Camera12 bit Point Grey Di it l Fi iDigital Firewire camera.• Calibrated against a
Prometric Still L i CLuminance Camera
Varying shutter and gain values determine gthe range of luminance measured• 2 cameras can be• 2 cameras can be
coupled to increase dynamic response
Individual images areIndividual images are stored for later analysis
Luminance Camera
ResultsThe results were analyze using ANOVA techniques
Source F value P value SignificantLighting Type 5.00 0.0011 *Lighting Level 10.24 0.0037 *Lighting Type* Lighting Level 3.00 0.0225 *Lighting Class 4.06 0.0004 *
All factors and their interaction were significant
Lighting Level Comparisong g p
70Lighting Section Comparison
B
A
60
70
(m)
C
B, C B, C B, C
40
50
ion
Dis
tanc
e
20
30
Mea
n D
etec
ti
0
10
250W Dimming Beta LED Kim Induction Lumecon LED Kim LED 400W Non
M
250W Dimming HPS
Beta LED Kim Induction Lumecon LED Kim LED 400W Non-Dimming HPS
Lighting Section
Lighting Levelg g
70Lighting Intensity Comparison
60
70
m)
40
50
on D
ista
nce
(m
20
30
Mea
n D
etec
tio
0
10
M
0High Low
Lighting Intensity
Lighting Type and Levelg g yp
70Lighting Class Comparison
A
A, B
A
A, B50
60
70
ce (m
)
C
B, CB, C B, C B, C
30
40
ectio
n D
ista
nc
C
10
20
Mea
n D
ete
0250W
Dimming HPS
Beta LED Kim Induction
Lumecon LED
Kim LED 250W Dimming
HPS
Beta LED Kim Induction
Lumecon LED
Kim LED
Low High
Lighting Class
Practical Differences400W HPS and Alternative Lighting Comparisons
-5
0250W Dimming
HPSBeta LED Kim Induction Lumecon LED Kim LED
)
Lighting Section
-20
-15
-10
Dis
tanc
e (m
)
-30
-25
20
in D
etec
tion Lower 95%
MeanUpper 95%
-40
-35
Diff
eren
ce
-50
-45
Illuminance Results25
Mean Illuminance Levels For Each Lighting Section
20
15
nce
(lux)
Left
5
10
ean
Illu
min
an
Front
Right
0250W
Dimming HPS
Beta LED
Kim Induction
Lumecon Kim LED
250W Dimming
HPS
Beta LED
Kim Induction
Lumecon Kim LED
400W Non-Dimming
HPS
Me
HPS HPS HPS
Low High Control
Lighting Class
Relationship to Illuminancep80
Mean Detection Distance and Illuminance Levels
60
70
30
40
50
Mean Illuminance Level (Lux)
0
10
20Mean Detection Distance (Meters)
0
W D
imm
ing
HPS
Bet
a LED
Kim
Indu
ctio
n
Lum
econ
LED
Kim
LED
400
W H
PS
W D
imm
ing
HPS
Bet
a LED
Kim
Indu
ctio
n
Lum
econ
LED
Kim
LED
400
W H
PS
250W
250W
Low High
Anchorage Observationsg400 Watt HPS provided the longest detection distance250 Watt HPS was the shortest detection distanceThe Broader Spectrum sources provided an improved visibility at a average lower horizontal ill i l lilluminance level.The lighting level significantly impacted D t tiDetection
Lighting Considerationsg gMesopic Effect• The eye is more sensitive to blue spectrum light
sources at low luminance levels
I h i b d h b dIs the improvement based on the broader spectrum sources a result of Light Sensitivity or more available information in the visualmore available information in the visual environment?• Further investigation is requiredg q
Further AnalysisyWe will be looking at the distances of detection for both the pedestrians and the objectsThe luminance, illuminance and contrast will all be assessed based on the measured results of the systemGl ill b d b d i hGlare will be attempted to be measured using the interior illuminance meter
Luminance Metrics
Applying multiple contrastApplying multiple contrast metrics to imagesSemi-automated processp1. Accesses database of
images for analysis2. User selects target3. Automatically calculates
contrast metricscontrast metrics
Luminance MetricsResults in luminance and contrast information
Mean Luminance of Target 0.677cd/m2 0.961cd/m2Mean Luminance of Target 0.677cd/m 0.961cd/mMean Luminance of Background 1.579cd/m2 1.492cd/m2
Weber Contrast -0.571 -0.356Simple Contrast 2.331031 1.552046 Mi h l C 0 399585 0 216315Michelson Contrast 0.399585 0.216315