Initially, manufacturers are finding it difficult to produce high-grade LED on how to replace the old lights are dumbfounded. However, the technology development over time, and now, the Greater Washington, London and Paris and other large cities have adopted the framework of this type of lighting. Challenges However, these kinds of apparatus is not cost-friendly, because they require a considerable amount of electric power function. After a lot of research and testing, to find a good selection of LED street light, scientists in the United States have developed. The change compared with the powered lamp, mercury and other chemicals, only need a smaller amount of power. They also produce a brighter light, and have a longer life. These prominent characteristics convince city officials not only in the United States, but also in different countries around the world, and gradually change the traditional lighting. . The lights on the street to play a crucial role, especially for drivers at night. It allows the vehicle traffic flow, and to prevent any unpleasant surprises, such as automobile collision and robbery. Businesses involved in these lights are to receive their high demand. In the 1990s, they used the volatile compounds, such as mercury in their bulbs.