Street lights have been a target for improvement among lighting experts for some time, and there are a number of approaches to improve their resource performance. One option is to focus on the energy use of the lamps themselves, replacing them with LEDs to increase efficiency. Another is to try to reduce the amount of resources tied up in the infrastructure associated with street lights. Phillips, for example, designed a "floating" street lighting system called FreeStreet, which consists of a series of LEDs connected via hanging cables, eliminating lampposts. And another approach has to do with precision. Lighting designers have used directional lamps and add-on devices to ensure that the light is directed downward.

Researchers at the National Central University in Taiwan and the Autonomous University of Zacatecas in Mexico are pursuing a new approach to precision. Their fixture contains a cluster of LEDs with a special lens that focuses the light rays so they’re parallel, rather than crossing over one another. The result of their design is light in a rectangular shape, offering a more precise match with the road surface that’s being lit. So, in addition to improving energy efficiency, the researchers have found a way to increase performance by using shape to get the light exactly where it’s needed.

For more technical details, you can read the research article published in Optics InfoBase. You can explore more on lighting at here.