Most LED street lights have a lens on the LED panel, which is designed to cast its light in a rectangular pattern, an advantage compared to traditional street lights, which typically have a reflector on the back side of a high-pressure sodium lamp. In this case much of the luminance of the light is lost and produces light pollution in the air and surrounding environment. Such street lights can also cause glare for drivers and pedestrians.
A drawback of LED focus panels is that most light is directed to the road, and less light to the footpaths and other areas. This can be addressed by the use of specialised lens design and adjustable mounting spigots.