LED roadway lighting offers a variety of benefits. They have a longer bulb life than HPS lamps. The lights currently last about 10-15 years and, unlike HPS lamps, they do not exhibit lumen decay as severely. Lumen depreciation is a phenomenon that occurs when the lumen output provided by a light source begins to degrade over time. HPS lights exhibit quicker luminosity decay after as few as 2,000 hours, incurring higher maintenance expenses.

Compared to LEDs, HPS lamps have a substantially shorter lifespan. While an LED light can last up to 200K hours, a typical HPS bulb lasts about 24K hours. Both HPS and LEDs maintain a sizable portion of their initial light output over the course of their lives; LEDs perform slightly better than HPS lamps, but they are comparable.

As we have learned from several postings, LEDs are a highly energy-efficient light source. According to the Environmental Security Technology Certification Program (ESTCP), after monitoring HPS street lights for a year and then retrofitting them with comparable LED street lights, they found that the LED system consumed around 75 percent less electricity than the previous HPS street lights. Another key benefit of LED street lights is they offer a strong light output regardless of temperature, although HPS bulbs often provide less visible light during colder temperatures. Not only is the light output of an LED street light better than an HPS bulb, but the CRI is substantially higher and light is spread more evenly with an LED. Most LEDs have a CRI rating between 70-92 whereas HPS lamps range between 20-30 on the CRI scale. The scale evaluates light quality from 0-to 100. Lastly, it should be remembered that HPS lights do not start at maximum brightness. They gently develop light after the preliminary ignition, whereas LEDs turn off and on without a ramping or light-generating phase.