Selection for Street Light Luminar-(PART-2)


Classification of Street:


Classification Roadway Traffic
Classification NumberNumber of Vehicles per Hour
Maximum Night HourBoth Direction
Very light trafficUnder150
Light traffic150500
Medium traffic5001200
Heavy traffic12002400
Very heavy traffic24004000
Heavy trafficOver4000


Classification of Pedestrian Traffic
Light or No TrafficResidential, warehouse areas on express / elevated depressed roadways
Medium TrafficSecondary business streets and some industrial roads
Heavy TrafficBusiness streets.


Mounting Height of Street Light Laminar:

  •  The distance the lamp is mounted above the roadway will affect the illumination intensity, uniformity of brightness, area covered, and relative glare of the unit.
  • Higher mounted units will provide greater coverage, more uniformity, and reduction of glare, but a lower illumination level.
  • It is necessary to weigh the effects of larger lamps against a greater number of smaller units at lower mounting heights with maximum glare potential.
  • The height of luminaries above the roadway surface varies from 5 Meter to more than 20 Meter.
  • Conventional roadway lighting utilized mounting height of 8 to 20 Meter. The lower mounting heights require the use of cutoff or semi-cutoff luminary’s distribution to minimize glare.

Height of PoleApplication
6 MeterFor streets ,alleys, public gardens and parking lots
8 MeterUrban traffic route, multiplicity of road junctions,
Narrow roads such as local access roads in residential areas in which a mounting height between 10 M or 12 M and 5 M or 6 M is required.
10 MeterUrban traffic route, For wide heavily used routes where a large number of intersection, bends can lead to a short spacing making the use of 12 M mounting height uneconomical.
12 MeterWide or heavily used routes where advantage can be taken of a longer spacing of luminaries.
18 Meter and aboveHigh mast lighting poles shall be installed at large-scale area such as airports, dockyards, large industrial areas, sports areas and road intersections

Type of RoadPolePole HeightLaminar WattType of Laminar
RuralAluminum or Steel Pole10 to 16 Meter250W to 400WHPS
UrbanAluminum10 to 13 Meter250W to 400WHPS (Cut off or Semi Cut off)

 High Mast Lighting Systems:

  • High mast lighting has 3 or 4 no’s of 1000 watt HPS luminaries mounted on poles /towers, at mounting heights (30 Meter). It develops a highly uniform light distribution.
  • Advantage:
  • Excellent uniformity of illumination, reduce glare with a substantially smaller number of pole locations.
  • Application:
  • Where continuous lighting is desirable such as lighting of toll plazas, rest areas ,parking areas, general area lighting, highways , traffic lanes.
  • High mast lighting is also desirable where there is minimal residential area.
  • High Mast used at remote location to eliminates the need for maintenance, vehicles obstructing traffic on the roadway.
  • High Mast having symmetric or asymmetric distribution
  • The design and installation of high mast lighting equipment is more complex than conventional lighting.


Correction Lamp Comparison Chart (Bureau of Energy Efficiency, Delhi)

Lamp TypeLamp ( Watts)Efficacy (Lumens /Watt)ColorRender


LampLife (Hr)Remarks
Incandescent (GLF) Lamps:
(Incandescent bulbs)15,25,40,60,75,100,150,200, 300,500               (no ballast)8 to 171001000 
Tungsten Halogen 75,100,150,500,1000,2000 (no ballast)13 to 251002000 
Fluorescent Tube lights(Argon filled)20,40,65, (32,51,79)31 to 5867 to 775000 
Fluorescent Tubular Lamp (T5)18,20,36,40,58,65100 to 120Very Good15,000 to 20,000 Energy-efficient,long lamp life,

only available in low wattages

Compact Fluorescent Lamps (CFLs)5,7,9,11,18,24,3626 to 64858000 
HID Lamps:
High Pressure MercuryVapor (HPMV)80,125,250,400,1000,200025 to 6045 (Fair)16,000 to 24,000High energy use,Poor lamp life
High Pressure   Metal Halide Lamps (HPMH)70,150,250, 400,1000,200062 to 7270 (Excellent)8000 to 12000High luminous efficacy, Poor lamp life
High Pressure SodiumVapor Lamps (HPSV)70,150,250,400,100069 to 10825 to 60 (Fair)15000 to 24000Energy-efficient, poor color rendering
Low Pressure Sodium Vapor Lamps (LPSV)35,55,13590 to 133Very Poor18000 to 24000Energy-efficient, very poor color rendering
Low Pressure Mercury   Fluorescent TubularLamps (T8 & T12)35,55,13530 to 90Good5000 to 10000Poor lamp life, medium energy use, only available in low wattages
LED Lamps
Light Emitting Diode (LED) 70 to 160Good40,000 to   90,000