Streetlight Optics Optics for Streetlights Most streetlights are designed to control light distribution. There are three types of optical systems that provide different degrees of control. Non-cutoff optics, allow light to be emitted in all directions.
Many decorative fixtures use non-cutoff fixtures.
Non-cutoff optics are the least efficient way to put light on the ground. They are generally effective at throwing light up into trees, and create a large amount of light pollution and glare. These lights are not generally used as prinicpal light sources on thoroughfares, as the glare has the tendency to blind drivers. Semi-cutoff optics, allow most of the light to be emitted below 90 degres, but some light to be emitted above 90 degrees. These types of optics are commonly used in cobra-head style streetlighting.