In the United States alone, several major cities, including Seattle, Portland, San Francisco, Oakland, Las Vegas, Austin, New York, and Boston, have either switched to LED street lighting or are planning an LED retrofit. Shanghai and Copenhagen have joined the list of international cities that are relying on LED systems to light their streets. The forces that gave rise to this trend are not difficult to understand.
LED systems generate the same or better illumination while using less than half of the electrical power that is consumed by traditional high pressure sodium street lighting fixtures. Lower power consumption translates directly into lower utility bills for cities that might be struggling with limited budgets. Newer LED fixtures also provide more than 50,000 hours, and in some cases up to 100,000 hours of operation without failure, which substantially reduces maintenance expenses. A city might be reluctant to retrofit to an LED street lighting system due to high upfront costs, but the cost savings that a city will realize from switching to LED lights will quickly pay for the systems themselves and will generate longer-term economies for those cities. Moreover, as LED street lighting becomes more common, those upfront costs will inevitably drop as manufacturers gain economies of scale with greater production.
LED street lights and fixtures can be configured to generate consistent and uniform light across all street surfaces with no dark zones or shadows. This versatility improves the safety of both pedestrians and motorists on city streets. Although some physicians’ groups have commented that the wavelengths of LED street lights are adversely affecting city residents because of their higher concentrations of wavelengths in the blue spectrum (which can interfere with sleep patterns), next generation LED street lighting reduces that spectrum with no degradation in illumination or performance.
LED systems come to full illumination almost immediately after they are powered on. They can be dimmed in the middle of the night, when foot and motor traffic is lower, to further reduce electricity consumption. Advanced control systems allow city planners to adjust lighting levels of individual luminaires or groups of fixtures in response to different demands that occur throughout the evening. Unlike traditional street lighting that is generally limited to on-off operation, LED systems provide an almost infinite number of control options.
LED fixtures contain no hazardous materials and have a substantially lower carbon footprint, both in manufacturing and operation, than virtually every other type of industrial lighting. Cities that have retrofitted to LED systems have also experienced a reduction in light pollution because LED lighting is more directional, with less leakage of unwanted light into areas outside of the surfaces that a city wants to illuminate.