Considering the economic benefits and efficiency, they emphasize the object visibility especially the lower average illumination for America roads and road lighting. Therefore, their road lights are designed higher than those in our country. They have low requirements for illumination uniformity as well as brightness on the roads. However, they strictly control the glaring of the road lights for better object visibility and to avoid disturbing their people. By contrast, the electricity loss for America road lighting is lower and their requirements for illumination distribution are higher.
As the power of most road lights is supplied by electricity network, most of the road lights have self-adaptive control and new LED road lights can be controlled by the illumination adjustment. In April of 2013, new standards for remote control and self-adaptive control of road lights are announced, which established a frame for the future LED products and system control.
At present, the color temperature issue of road lights is still under discussion due to different application occasions. The white light is preferred for the safety of the busy cities and streets. The color temperature is lower for the traditional streets, residential areas, and roads in the suburbs areas. At the preliminary stage, the LED lights installed have high color temperature, which can be adjusted in the scale of 3500K to 5000k.
The biggest uncertain factor is the payback of LED road lights. In another word, it takes a long term to verify the lifecycle reliability of the lamps. LM-80 and LM-79 are required to control the light decay and illumination efficiency.
The failure in the early stage and reliability can only be checked by products quality control. Only 30% of the samples provided can meet the target, of which only one third can be finally used. Around 10% of the products can be accepted for final test and only 2% can pass the strict sorting for the expected results, 0.2% of the failure rate.