What is LED? How it works? Inside of an LED LED lighting Advantages of LED lighting Disadvantages of LED lighting Automotive LED lighting Road Lighing

1. Automotive Lighting
Led Road Lighting
CANER GÖKSEL SONUZUN

2. Contents
• What is Led?
• How it Works?
• Inside of an Led
• Led Lighting
• Advantages of Led Lighting
• Disadvantages of Led Lighting
• Automotive Led Lighting
• Road Lighting

3. What is Led?
• A light-emitting diode (LED) is a two-lead semiconductor light
source. It is a pn-junction diode, which emits light when
activated.

4. How it Works?
• When a suitable voltage is
applied to the leads, electrons
are able to recombine with
electron holes within the
device, releasing energy in the
form of photons. This effect is
called electroluminescence,
and the color of the light
(corresponding to the energy
of the photon) is determined
by the energy band gap of the
semiconductor.

5. Inside of an LED

6. Led Lighting
• With the development of high-efficiency
and high-power LEDs, it has become
possible to use LEDs in lighting and
illumination. Replacement light bulbs have
been made, as well as dedicated fixtures
and LED lamps.
• An LED lamp is a light-emitting diode
(LED) product that is assembled into a lamp
(or light bulb) for use in lighting fixtures.
LED lamps have a lifespan and electrical
efficiency that is several times better than
incandescent lamps, and significantly better
than most fluorescent lamps, with some
chips able to emit more than 100 lumens
per watt

7. Advantages of Led Lighting
• LED (Light Emitting Diodes) are the latest and most exciting
technological advancement in the lighting industry. LEDs are small,
solid light bulbs which are extremely energy efficient and long
lasting. LEDs operate differently than traditional incandescent light
bulbs. This makes LEDs far more rugged and durable than traditional
incandescent light bulbs. LED technology also offers many additional
advantages over incandescent, neon and compact fluorescent lighting
devices - such as exceptionally longer life span (60,000 hours),
enormously lower energy usage (90% more efficient), reduced
maintenance costs and higher safety. LEDs are currently being used
for a wide variety of applications such as: residential lighting,
aerospace, architectural lighting, automotive, aviation, broadcasting,
electronic instrumentation, entertainment and gaming, industrial
automation and controls, the military, traffic and safety &
transportation.

8. Advantages of Led Lighting
Efficiency
• LEDs are extremely energy efficient and consume up to 90% less power
than incandescent bulbs. Since LEDs use only a fraction of the energy of
an incandescent light bulb there is a dramatic decrease in power
costs. Also, money and energy is saved in maintenance and replacement
costs due to the long LED lifespan.
• Because of the low power usage of LEDs, they are becoming extremely
popular for light sources in remote areas that use solar panels.
• Although LEDs have a higher initial cost than incandescent and compact
fluorescent light bulbs, the cost is quickly recouped over time in lower
electricity costs.

9. Advantages of Led Lighting
Longevity
• LEDs have a lifespan of up to 60,000 hours compared to 1,500
hours for incandescent bulbs. An LED light will last over 7
years (constant use) before needing replacement. On average,
LED bulbs last 10 times as long as compact fluorescent bulbs,
and 133 times longer than typical incandescent bulbs. Long
lifespan of LEDs will dramatically reduce maintenance costs
and lower long-term operating costs compared to traditional
incandescent and fluorescent tubes.
LED lifespan scenarios:
• 50,000 hours powered 4 hours/day = 34 year lifespan
• 50,000 hours powered 8 hours/day = 17 year lifespan
• 50,000 hours powered 24 hours/day = 6 year lifespan

10. Advantages of Led Lighting
Durability
• LEDs are solid state lighting devices that utilize semiconductor
material instead of a filament or neon gas. An LED light is a
tiny chip encapsulated in an epoxy resin enclosure, which
makes LEDs far sturdier than traditional incandescent light
bulbs or fluorescent tubes. Since LEDs don't use fragile
components such as glass and filaments, LEDs are able to
withstand shock, vibration and extreme temperature.

11. Advantages of Led Lighting
Safety
• Improved safety may be LED's most important benefit
• LED lights generate virtually no heat therefore they are cool to
the touch and can be left on for hours without incident or
consequence if touched. LED's produce 3.4 btu's/hour,
compared to 85 for incandescent bulbs. In comparison,
incandescent lighting expels 90% of the energy it consumes via
heat, making the bulbs hot to the touch. LEDs reduce the
potential for safety risks such as burns and fires.

12. Advantages of Led Lighting
Environment
• LEDs are made from non toxic materials, unlike fluorescent lighting
that uses mercury that may pose a danger to the environment. LED’s
are also recyclable and considered “green” or Earth-Friendly.
Color
• LED lights are offered in a variety of base colors such as Red, Green,
Blue and Amber. Because traditional incandescent light bulbs use
filters to produce colors, they are extremely inefficient. LEDS can be
blended together to produce millions of color options.
Future
• LEDs are poised to replace traditional incandescent light bulbs. LEDs
are rapidly becoming the preferred lighting solution of both
professionals and residential users. LED technology is continually
advancing - producing brighter LED bulbs. The U.S. Department of
Energy hopes to reduce the electricity used for lighting by 50% by
converting to LED based light sources.

13. Disadvantages of Led Lighting
• LEDs are currently more expensive, price per lumen, on an initial
capital cost basis, than more conventional lighting technologies.
However, when considering the total cost of ownership (including
energy and maintenance costs), LEDs far surpass incandescent or
halogen sources and begin to threaten compact fluorescent lamps.

14. Disadvantages of Led Lighting
• The Chart Below compares different light sources based upon
the life of the bulb and the electrical cost at 10 cents per kWh
(kilowatt hour). Note: fixture costs and installation costs are
not included.

15. Disadvantages of Led Lighting
• LED performance largely depends on correctly engineering the
fixture to manage the heat generated by the LED, which causes
deterioration of the LED chip itself. Over-driving the LED or
not engineering the product to manage heat in high ambient
temperatures may result in overheating of the LED package,
eventually leading to device failure. Adequate heat-sinking is
required to maintain long life. The most common design of a
heat sink is a metal device with many fins, which conducts the
heat away from the LED.
• LEDs must be supplied with the correct voltage and current at
a constant flow. This requires some electronics expertise to
design the electronic drivers.
• LED’s can shift color due to age and temperature. Also two
different white LED will have two different color
characteristics, which affect how the light is perceived.

16. Automotive Led Lighting
• Light emitting diodes (LED) are becoming more and more
significant in interior and exterior automotive lighting. The
long service life, energy and space savings, shock and
vibration resistance and new styling potential are the main
advantages of using LEDs in automotive applications. Today,
most central high mounted stop lamps use LEDs. In rear
combination lamps the number of LEDs in amber and red is
increasing rapidly. This year, a first rear combination lamp
using LEDs for all functionalities including the back-up lamp
function was realized. In addition, first signal functions in
headlamps using white High Power LEDs were launched onto
the market. The long service life characteristic makes LEDs
especially predestined for the DRL function combined with the
position/parking light.

17. Automotive Led Lighting -
Headlamps
Headlamps
Automotive headlamp applications using light-emitting diodes
(LEDs) have been undergoing very active development since 2004.
• In 2004 the Audi A8 W12 became the first production car to use
LED headlight technology, for the integrated daytime running
lamps
• In 2006 the first series-production low beam, front position light
and sidemarker function LED headlamps were factory-installed on
the Lexus LS 600h / LS 600h L presented in 2007 for 2008
models. The high beam and turn signal functions use filament
bulbs. The headlamp is supplied by Koito.

18. Automotive Led Lighting -
Headlamps
• In 2009 Hella headlamps on the 2009 Cadillac
Escalade Platinum became the first US market all-LED
headlamps.
• In 2010 the first all-LED headlamps with Adaptive
highbeam and Intelligent Light System were introduced
on the 2011 Mercedes-Benz CLS-Class: LED High
Performance headlamps.
• In 2012 the first mechanically controlled LED glare free
headlamps were introduced on BMW 7 Series Selective
Beam (anti-dazzle High-Beam Assistant).

19. Automotive Led Lighting -
Headlamps
• In 2013 a (State of the art): First digitally controlled, full-LED glare-
free adaptive highbeam. It was introduced by Audi on the facelifted
Audi A8 in 2013, with 25 individual LED segments (Matrix LED).
The system dims light that would shine directly onto oncoming and
preceding vehicles, but continues to cast its full light on the zones
between and beside them. This works because the LED high beams
are split into numerous individual light-emitting diodes.high-beam
LEDs in both headlights are arranged in a matrix and adapt fully
electronically to the surroundings in milliseconds. They are activated
and deactivated or dimmed individually by a control unit. In addition,
the headlights also function as a cornering light. Using predictive
route data supplied by the MMI navigation plus, the focus of the
beam is shifted towards the bend even before the driver turns the
steering wheel. In 2014: Mercedes-Benz introduced a similar
technology on the facelifted CLS-Class in 2014, called
MULTIBEAM LED, with 24 individual segments.

20. Automotive Led Lighting -
Headlamps
• Designs as of MY2010, such as
those available as optional
equipment on the 2010 Toyota
Prius, give performance between
halogen and HID headlamps, with
system power consumption slightly
lower than other headlamps, longer
lifespans and more flexible design
possibilities. As LED technology
continues to evolve, the
performance of LED headlamps is
predicted to improve to approach,
meet, and perhaps one day surpass
that of HID headlamps

21. Automotive Led Lighting -
Headlamps
• The limiting factors with LED headlamps presently include high system
expense, regulatory delays and uncertainty, and logistical issues created
by LED operating characteristics. As a semiconductor, the performance
of an LED is dependent on its temperature; a given diode will produce
more light at a low temperature than at a high temperature. Thus, in order
to maintain a constant light output, the temperature of an LED headlamp
must be kept relatively stable. LEDs are commonly considered to be low-
heat devices due to the public's familiarity with small, low-output LEDs
used for electronic control panels and other applications requiring only
small amounts of light; however, LEDs actually produce a significant
amount of heat per unit of light output. Rather than being emitted
together with the light as is the case with conventional light sources, an
LED's heat is produced at the rear of the emitters. Unlike incandescent
and HID bulbs, LEDs are damaged by high temperatures; prolonged
operation above the maximum junction temperature will permanently
degrade the LEDs and ultimately shorten the device's life. The need to
keep LED junction temperatures low at high power levels requires
thermal management measures such as heatsinks or cooling fans which
are typically quite expensive.

22. Automotive Led Lighting -
Headlamps
• Additional facets of the thermal issues with LED headlamps
reveal themselves in cold ambient temperatures. Not only can
excessively low temperatures lead to the LED's light output
increasing beyond the regulated maximum, but heat must in
addition be effectively applied to thaw snow and ice from the
front lenses, which are not heated by the comparatively small
amount of infrared radiation emitted forward with the light
from LEDs.
• LEDs are increasingly being adopted for signal functions such
as parking lamps, brake lamps and turn signals as well as
daytime running lamps, as in those applications they offer
significant advantages over filament bulbs with fewer
engineering challenges than headlamps pose.

23. Road Ligting
• Basic Principles of Streetlight Design
• Design Considerations
• Customer Requirements
• Light Pollution
• Basic Lighting Design
• Luminaire Selection

24. Basic Principles of Streetlight
Design
• 1. Safety – pedestrian and driver safety. Creating a lighting
level sufficient that drivers are aware of any pedestrians and or
objects near the roadway.
• 2. Security – providing a setting that will deter some forms
of criminal activity through the use and placement of lights.
• 3. Limit the amount of Light Trespass – avoiding the over
lighting of areas such as in residential neighbourhoods where
the backlight may shine on houses.
• 4. Environmental Responsibility
• 5. To provide uniformity and consistency in lighting designs
throughout the province while meeting the industry standard.

25. Design Considerations
• When starting a lighting design, attention to the surrounding
area and any special requirements must be taken into
consideration, ie…schools, shopping districts, or airports.
• It is important to note that there are three different design
methods that can be used for calculating the roadway lighting
levels. Each method may produce different designs and
provide different amounts of lighting levels through luminaire
spacing and configurations. Each of these methods is
acceptable and the preferred method SaskPower uses will be
indicated later in this document. The three types are the
Illuminance Method, Luminance Method and Small Target
Visibility Method.

26. Customer Requirements
• SaskPower’s standard practice is to design roadway lighting as
per TAC standards. There are situations where a customer may
not wish to have streetlights designed to this standard, often
due to the cost. If customer does not want to meet TAC
requirements, they are required to sign a Streetlighting Waiver
Form before SaskPower will install the streetlights. SaskPower
will not install lighting facilities that do not meet the TAC
requirements without this waiver as it would leave SaskPower
open to liability.

27. Light Pollution
Light pollution is becoming an increasing concern and typically
takes one of two forms:
Light trespass or back lighting where there is an excessive amount
of light towards a residence. Certain homeowners are particularly
sensitive to light coming into their homes from streetlights and
complain of sleep disruption, etc. While our typical luminaires do
a reasonable job of controlling the light toward the residence,
there have been complaints from homeowners regarding
excessive light trespass. Mitigation may require selection of
different luminaires, repositioning luminaires or the addition of
light shields to block the light.

28. Light Pollution
• Up-lighting where there is excessive light upwards from the
luminaire. This will impact visibility of the night sky and is a
particular concern among astronomers. The International Dark-
Sky Association (IDA) is an organization which promotes the
use of luminaires with zero uplight (ie. Full Cut-off). They will
assess luminaires and provide a Fixture Seal of Approval
(FSA) for luminaires which meet their requirements for
Uplighting. As of the writing of this document, the City of
Saskatoon has required SaskPower install Full Cut-off lights

29. Basic Lighting Design
• Roadway Terminology
• Lighting Design Methodology
• Pedestrian Conflict
• Light Arrangement Styles
• Pavement Classification
• Area Classifications
• Light Calculation Grid
• Light Loss Factors

30. Roadway Terminology
• Roadway – The portion of the road surface, including
shoulders, for vehicular use.
• Traveled Way – The portion of the roadway provided for the
movement of vehicles, exclusive of shoulders, auxiliary lanes
and bicycle lanes.
• Median – The portion of the roadway separating the traveled
way for accommodation of stopped vehicles for emergency
use, and for lateral support of the base and surface courses.
• Median – The portion of the roadway separating the traveled
way for accommodation of stopped vehicles for emergency
use, and for lateral support of the base and surface courses.
• Sidewalk – An exterior pathway with a prepared surface
(concrete, bituminous, brick, stone, etc.) intended for
pedestrian use.

31. Roadway Terminology
• Setback – The distance from the streetlight pole to the front of the curb.
• Arm Length – The distance from the approximate location of the bulb to
the center of the vertical part of the light standard/pole. The typical arm
length is 2.40m.
• House-side Lateral Distance – the distance from the imaginary vertical line
directly below the luminaire and running back toward the adjacent curb.
Also referred to as “Overhang”.
• Street-side Lateral Distance – the distance from the imaginary vertical line
directly below the luminaire to the curb on the opposite side of the
roadway.
• Mounting Height – the distance from the location of the bulb to the road
surface directly below. The typical steel streetlight standard heights are:
25’, 30’, 35’, 40’, and 45’. There are also typical wood pole mounted
streetlights.

32. Roadway Terminology

33. Lighting Design Methodology
• There are three lighting design methodologies – Luminance,
Illuminance and Small Target Visibility (STV). Luminance measures
the incident lighting on the roadway while illuminance is a measure
of the reflected light.
• Small Target Visibility (STV) differs from Illuminance and
luminance design in that values are given in terms of a weighted
average visibility level. This is a relatively new design method
adopted in 2000 by IESNA and has come under scrutiny within
roadway lighting community. At this time STV should be used only
as a method for assessing different lighting designs, and not as the
primary method of calculation.
• The Luminance method shall be used for roadway and interchange,
the Illuminance method shall be used for intersections and cul-de-
sacs. Lighting designs for curved sections with greater than 600m
radius should be evaluated as if it were a straight section, otherwise
they should be evaluated as an intersection.

34. Pedestrian Conflict
• The next step in developing a Roadway Lighting Design is to
identify the amount of pedestrian traffic in the area to establish
the Average Illuminance, Average to Minimum Uniformity
Ratio and Minimum Illuminance.
• According to IES RP-8-05, there are three types of
classifications.
• Low conflict area: residential
• Medium conflict areas: schools, recreational centers
• High conflict areas: restaurants, shopping, theatres

35. Pedestrian Conflict
• Pedestrian Conflict is assumed to be the total number of people
on both sides of a street within a given section (200 meters).
This number also includes those people crossing the street
between the hours of 18:00 and 19:00.
LOW : 10 or fewer pedestrians
MEDIUM : 11 to 100 pedestrians
HIGH : over 100 pedestrians
Table - Classification of
Pedestrian Conflict

36. Pedestrian Conflict

37. Light Arrangement Styles
There are several options available for the placement of lighting
standards. Some of these are as follows:
• One Sided Arrangement

38. Light Arrangement Styles
• Two Sided Opposite Arrangement
• Two Sided Staggered Arrangement

39. Light Arrangement Styles
• Double Davit Median Arrangement

40. Light Arrangement Styles
• Double Davit Opposite Arrangement

41. Light Arrangement Styles
• Double Davit Staggered Arrangement

42. Pavement Classification
• The first step in developing the Roadway Lighting Design is to
determine the Pavement Classification. Pavement classification
is a measure of how reflective the roadway surface is to
establish the lighting levels required. The pavement
classification will establish the Q0 Mean Luminance
Coefficient.
• The four pavement classifications in TAC are R1, R2, R3, and
R4. The R represents the reflective quality of the pavement.
For SaskPower, a typical roadway would be represented by a
R3 classification.

43. Pavement Classification
MODE OF
CLASS QO DESCRIPTION OF ROADWAY SURFACE REFLECTANCE
Portland cement concrete road surface. Asphalt road
R1 0.10
surface with a minimum of 15 percent of the
Mostly Diffuseaggregate composed of artificial brightener *(e.g.
Synopal) aggregates (e.g. Labradorite, quartzite)
An asphalt road surface with an aggregate
R2 0.07
comprised of minimum 60% gravel (size greater Mixed (diffuse and
than 10mm). Asphalt road surface with 10-60% specular)
artificial brightener in aggregate mix.
An asphalt road surface (regular and carpet seal)
R3 0.07
with dark aggregates ( e.g. trap rock, blast furnace
Slightly Specularslag); rough texture after some month of use
(typical highways).
R4 0.08 Asphalt road surface with very smooth texture Mostly Specular
Copied from TAC 2-37 2006
Table - Pavement Classification

44. Area Classifications
• In order to determine appropriate lighting levels, it is important to consider what
the land adjacent to the roadway is being used for, and in particular to identify the
amount of pedestrian and vehicular traffic. There are three classifications:
• Commercial. A business area of a municipality where ordinarily there are
many pedestrians during night hours. The definition applies to densely
developed business areas outside, as well as within, the central part of
municipality. The area contains land use which attracts a relatively heavy
volume of night time traffic vehicular and or pedestrian traffic on a frequent
basis.
• Intermediate. Those areas of a municipality often characterized by
moderately heavy night time pedestrian activity such as in blocks having
libraries, community recreation centers, large apartment buildings, industrial
buildings or neighbourhood retail stores.
• Residential. A residential development, or a mixture residential and small
commercial establishments, characterized by few pedestrians at night. This
definition includes areas with single family homes, town houses, and or small
apartment buildings.

45. Light Calculation Grid
• Setting up a grid in lighting design software should be as per
IESNA RP-08-05. Using more or less points will alter the
calculations and you may or may not achieve the proper lighting
levels. As well any change of the grid spacing’s will also have an
effect upon the calculations.
• The following criteria should be applied:
• The grid should be based on the number of lanes for the majority of
the length of roadway.
• In the event that the roadway width and number of lanes change,
then a revised grid should be used for the new length of roadway.
• In the longitudinal direction, the distance between grid lines should
be one-tenth (1/10) of the spacing between luminaires, or 0.5m,
whichever is smaller. The starting point for the gridlines should not
be located directly under a pole, but should start instead at a point
one-half (1/2) of the grid cell size from the luminaire pole.

46. Light Loss Factors
• Light Loss Factors (LLF) are multiplier values to estimate the overall
performance at different times during the life of the lighting system.
LLF values reflect the performance of the lamp and luminaire as well
as the maintenance level of a lighting system. The LLF are:
• Lamp Lumen Depreciation (LLD)
• Luminaire Dirt Depreciation (LDD)
• Luminaire Ambient Temperature Factor (TF)
• Ballast Factor (BF)
• Equipment Factor (EF)
• The Light Loss Factor can be summed up as:
LLF = LLD x LDD x TF x BF x EF

47. Light Loss Factors
• LLD Lamp Lumen Depreciation
LLD is the reduction in the light output as the lamp ages. The
rated Lumen are provided by the manufacturer based upon 100
hours of usage. The can be shown as ‘Lumen Depreciation
curves”. The typical LLD factor for high pressure sodium vapour
base on 5 year maintenance group re-lamping program is 0.78.
• LDD Luminaire Dirt Depreciation
LDD takes into account the luminaire output depreciation due to
an accumulation of dirt on the luminaire and in the air. The
designer should pick a ‘clean’ LDD value in most situations
unless in an area of heavy manufacturing or areas prone to dust
storm use moderate LLD value. The typical LDD value for a five
year maintenance cycle adopted by SaskPower is 0.88.

48. Light Loss Factors
• TF Luminaire Ambient Temperature Factor
TF accounts for variations in lumen output based on ambient
temperature. HPSV luminaires are not affected significantly by ambient
termperature, the TF adopted by SaskPower is 1.0.
• BF Ballast Factor
BF is meant to cover reductions in light output due to the ballast. For
HID sources it is assumed to be 1.0 unless otherwise noted by the
manufacturer.

49. Light Loss Factors
• EF Equipment Factor
EF is used to account for other reductions in light output due to
the equipment used such as:
• manufacturing tolerances for both the luminaire and lamp
• luminaire depreciating over time (reflective surface)
• input voltage that varies from location to location SaskPower has
adopted an Equipment Factor of 0.95

50. Luminaire Selection
• Lateral Light Distribution
• Vertical Light Distribution
• Cutoff Optics
• Lighting Sources
• SaskPower Luminaire Models

51. Lateral Light Distribution
• Lateral Light Distribution is the lighting pattern the luminaire
puts out on the roadway. There are five types classified as Type
I through V. The higher the Distribution Type number, the
more light that will be spread across the roadway
• Type I - Usually used for median mounting.
• Type I, Four Way – Mainly used for intersection lighting. This
light provides four beams of light from one light standard. An
uncommon item and not very popular, would be placed in
middle of intersection for proper lighting.

52. Lateral Light Distribution
• Type II – Used to light the street front, not much light provided
on the back side of the luminaire.
• Type II, Four Way – Mainly used for intersection lighting.
Provides four beams of light and is installed on a corner. This
is an uncommon item and not very popular for lighting.

53. Lateral Light Distribution
• Type III – Provides the majority of light to the roadside of the
luminaire while the backside does not project as much light.
• Type IV - Provides the majority of light to the roadside of the
luminaire while the backside does not project as much light.
The Type IV puts light out further from the curb than a Type
III.

54. Lateral Light Distribution
• Type V – Ideal to be installed in the center of the intersection
and puts out a light pattern that is evenly dispersed around its
axis.
• Type V Quadrate – has a square form of light pattern around its
axis.

55. Vertical Light Distribution
• Vertical light distribution is divided into three categories,
Short, Medium and Long as illustrated in Figure 5-10.
Classification is on the basis of the distance from the luminaire
to where the beam of maximum candlepower strikes the
roadway surface. The classifications are:
• Short Distribution – The maximum candlepower beam strikes
the roadway surface between 1.0 and 2.25 times mounting
heights distance from the luminaire. See Figure 5-11.
• Medium Distribution – The maximum candlepower beam
strikes the roadway surface between 2.25 and 3.75 times
mounting height distance from the luminaire.
• Long Distribution – The maximum candlepower beam strikes
the roadway surface between 3.75 and 6.0 times mounting
height from the luminaire.

56. Vertical Light Distribution
• On the basis of the vertical light distribution, theoretical
maximum candlepower beams from adjacent luminaires are
joined on the roadway surface. With this assumption, the
maximum spacing of luminaires are:
• Short Distribution – 4.5 X mounting heights
• Medium Distribution – 7.5 X mounting heights
• Long Distribution – 12.0 X mounting heights
• From a practical standpoint, the medium distribution is
predominantly used in practice, and the spacing of luminaires
normally does not exceed five to six times mounting heights.
Short distribution is not used extensively for economic
reasons, because extremely short spacing is required. At the
other extreme, the long distribution is not used to any great
extent because the high beam angle of maximum candlepower
often produces glare.

57. Vertical Light Distribution

58. Half
Maximum
Candlepower
Projection

59. Cutoff Optics
• The amount of glare generated by a luminaire is strongly
influenced by the intensity (candle-power) emitted at angles
close to the horizontal. The cutoff classification is based on the
intensity of rays emitted at 80-degrees and 90-degrees vertical
angle. As the intensity of either of these angles will vary in
different vertical planes for typical roadway luminaires, the
maximum intensity considering all planes is used
• Non-Cutoff
• no intensity limits apply.
• are designed to allow for light to be emitted in all directions.
These are the least efficient of the four types to light a roadway
due to the amount of light pollution and glare they produce. Post-
top lights without shrouds or shielding are often Non-Cutoff.

60. Cutoff Optics
• Semi-Cutoff
• are designed so that the intensity at 80 degrees vertical angle must
not exceed 20% of the rated lamp lumens, and the intensity at 90
degrees must not exceed 5 % of the rated lamp lumens.
• are designed to allow the majority of light to be emitted below 90
degrees, with up to 5% allowed to be emitted above 90 degrees.
The most common type of light that fits this description is the
Cobrahead.

61. Cutoff Optics
• Cutoff
• has more controlled emitted light than semi-cutoff. Less than 2.5%
of the emitted light is allowed to escape the fixture above 90
degrees. The light spread is greater than a full cutoff, and the
spacing is not as far apart as a semi-cutoff.
• are designed so that the intensity at 80 degrees vertical angle must
not exceed 10% of the rated lamp lumens, and the intensity at 90
degrees must not exceed 2.5% of the rated lamp lumens.

62. Cutoff Optics
• Full Cutoff
• are designed so that light will only hit the ground below with no
light escaping above 90 degrees. The light is in a tight pattern on
the ground which requires the use of more lights than if one were
using any of the other three types of lamps.
• are designed so that the intensity at 80 degrees vertical angle must
not exceed 10% of the rated lamp lumens, and no light can be
emitted at 90 degrees or above. Full cutoff normally requires that
the luminaire have a flat bottom opening.
• Full Cutoff luminaires may have an International Dark Sky Fixture
Seal of Approval (see section 5.2 Light Pollution).

63. Cutoff Optics
 Luminaire Cutoff
Classification

64. Cutoff Optics
• Reduction of Glare with Full Cutoff Luminaire

65. Cutoff Optics
• Reduction in Light Trespass From Full Cutoff

66. Thank you for your
attention…
• Presented by
Caner Göksel Sonuzun.