NHTSA Forward Lighting research - Michael Perel
July 31, 2003 - JPOWERPOINT PRESENTATION


SLIDE 1
NHTSA Forward Lighting research 
Michael Perel, applied Vehicle research, NHTSA


SLIDE 2
OUTLINE
- glare complaints and problems
- differences between HID and Halogen headlamps
- factors affecting discomfort and disability glare
- hypotheses about glare complaints
- preliminary research findings
- future research directions


SLIDE 3
FORWARD LIGHTING GLARE CONCERNS
- over 4900 responses to request for comments on glare
- public wanted reduced glare from:
  * auxiliary lamps
 	+fog lamps
	+driving lamps
	+auxiliary low beam lamps
  * high-mounted headlamps
  * high intensity discharge (HID) lamps


SLIDE 4
GLARE CONSEQUENCES IDENTIFIED BY PUBLIC
- causes annoyance and road rage
- reduces vision
- increases difficulty of using mirrors
- distracts drivers; causes eyes to look away from road
- causes drivers to stop driving at night
- it hurts the eyes
- causes fear of being in crash


SLIDE 5
NATIONAL SURVEY
Glare has been: percent frequency
[bar chart]

- cause of Near miss 
- noticeable but acceptable 
- barely noticeable 
- not noticeable 


SLIDE 6
ONCOMING GLARE RATED 'DISTURBING' BY EACH AGE GROUP
[bar chart]
from Bureau of Transportation Statistics 2002, sample size 1373


SLIDE 7
KEY RESEARCH QUESTIONS
- why are drivers complaining about headlamp glare?

- what rulemaking options might reduce glare problems?
  * new photometric specifications
  * reduced mounting height
  * improved aim (static & dynamic)
  * others (e.g. washing systems, lamp color)


SLIDE 8
HID vs HALOGEN
HID: 3 primary points of forward illumination on the road

Halogen: broader band of forward illumination, "binocular" effect where lights converge

Color:
- blue/white vs. Yellow 

Horizonal Intensity:
- wide spread vs. limited spread


SLIDE 9
HID vs HALOGEN
[photos of front end of vehicles, headlamps on, dark, foggy conditions]
Intensity Gradient:
- sharp cutoff vs. gradual


SLIDE 10
[photos] 
Lens Optics: 2002 Mercedes Benz E/C class

Projector Optics: 2002 Audi A6

Complex reflector Optics: 2003 Acura RL


SLIDE 11
LAMP DESIGN DIFFERENCES
[chart]
 Lamp size (luminous area)
 Aiming methods


SLIDE 12
TWO TYPES OF GLARE:
Discomfort
- submective measured w/De Boer scale
- influenced by: illuninance from glare source, task difficulty, ambient brightness, angle from line of sight
- may affect performance through distraction and eye strain

Disability
- direct effect on visibility distance
- increases with glare intensity, driver age, and smaller angle from line of sight


SLIDES 13-14
[grey-scale contrast continuums]
ILLUSTRATION OF GLARE EFFECTS ON DETECTABILITY
contrast


SLIDE 15
[graphs]
SENSITIVITY OF EYE TO SPECTRUM


SLIDE 16
HYPOTHESES
- HID Blue Color: novelty attracts attention
- HID Blue Color: eyes more sensitive
- Wider beam pattern: drivers exposed to glare longer during meeting scenarios
- sharper intensity gradients: more sensitive to misaim, flickering
- smaller lamps: brighter luminance


SLIDE 17
NHTSA GLARE RESEARCH 
@ U of Iowa (completion: Fall 2003)
How do beam intensity distributions of HID lamps compare to halogen lamps? [graphs]


SLIDE 18
NHTSA GLARE RESEARCH 
@ U of Iowa (completion: Fall 2003)
How do seeing distances and glare compare for HID and  halogen lamps under different meeting scenarios, lamp aim, and mounting heights? [graphs]


SLIDE 19
NHTSA GLARE RESEARCH 
@ U of Iowa (completion: Fall 2003)
Do drivers take longer or more frequent glances at bluish headlamps? [photos]


SLIDE 20
NHTSA GLARE RESEARCH
(@ RENSSELAER'S LIGHTING RESEARCH CENTER, COMPLETION 6/2003)

- illuminance: 0.2, 1, 5 lx (500, 2500, 12500 cd)
- spectrum: halogen, blue-filtered halogen, HID
- size/luminance: 9 cm(2)/1400000 cd/m(2), 26cm/2/480000 cd/m(2), 77 cm(2)/ 16000 cd/m(2)


SLIDE 21
PRELIMINARY FINDINGS
[table]

Disability Glare
 - illuminance: SIGNIFICANT
 - spectrum: not significant
 - size: not significant

Discomfort glare
 - illuminance: SIGNIFICANT
 - spectrum: HID SIGNIFICANT
 - size: not significant but trend


SLIDE 22
PRELIMINARY CONCLUSIONS:
INTENSITY, SPECTRUM, LAMP SIZE
- Current FMVSS method to photometer lamp intensity seems sufficient to predict disability glare for foveal and peripheral vision

- for discomfort glare:
  * illuminance has greatest effect (implications for beam intensity and aiming)
  * spectrum is much smaller effect (HID is more discomforting)
  * size much less so


SLIDE 23
NHTSA GLARE RESEARCH
(@ RENSSELAER'S LIGHTING RESEARCH CENTER, COMPLETION 6/2003)

Feasibility of an adaptive headlight system which reduces intensity on lighted roads

Objectives:
 - measure visual performance with reduced headlamp intensity on lighted roads

 - determine improvement in discomfort and disability glare from reduced headlamp intensity


SLIDE 24
FUTURE GLARE RESEARDCH
- Use photo-logging technique to study real world glare exposure and effects on driving behaviors (2003-2004)

SLIDE 25
FUGURE RESEARCH (2003-2004)
- Determine effect of duration & intensity of HID glare exposure on visual recovery time

- quantify the level of misaim of different headlamp designs; assess effect of lens degradation

- further exploration of Adaptive Forward Lighting to determine its effect on visibility and glare