Optical Distribution Types I-V

Selecting the best Distribution Type 

Searching for the best distribution types although this information is very simplistic, the end goal is to improve the lighting quality for your lighting projects. The site geometry for your design plays an important role in selecting the best luminaire distributions. For example, a large shopping area may require very broad distributions while a smaller site near a residential neighborhood may require better spill light control. Projects that only use one distribution are inherently not able to provide adequate lighting levels and optical control. Using an improper distribution may require you to add more poles to meet your lighting criteria. The term “distribution type” defines how far forward of the luminaire (i.e., on the street side) the effective output reaches. The specific classification of distribution types is based on locating the luminaires effective major output pattern on a grid representing distances in units of Mounting Height (MH) from the luminaire. Below are generic patterns to better illustrate the overall pattern and possible application areas.





Type I is inteded for walkways, roadways or any narrow paths. Typically known for it's two-way lateral distribution having a preferred lateral width of 15° at the cone. Type 1 focuses majority of its light near the center of the pathway for even light disbursement since the light projects laterally at a 15° angel.


Type II distribution is well suited for expanded walkways, entrance roadway lighting and other applications. Having a lateral width of 18-29° means this type is meant for lighting larger areas.


Type III distribution is well suited for roadway lighting, general parking areas and other areas where a larger area of light is required because it gives more coverage further from the point source outward.  Type III distribution provides a wide, round pattern and yields an even light disbursement since the light projects outwards.


Type IV distribution is best inteded for sides of buildings and walls because of it's semicircular light pattern. Type IV has a preferred lateral width of 60° make it ideal for parking area and court yard.



Type V distribution is intended for mounting at or near center of roadways, center islands of parkways or an intersection. Type V provides central circular or square design pattern, equally across all angles from a central point.  It provides the most even pattern of light since light is pushed in all direction from the center.