- How big is the City’s street light program and why is it important?
- Why are you switching to LEDs?
- How much will this cost us?
- How much energy exactly?
- I’ve heard the new LED lights look different. Is that true?
- They seem brighter, though. Are they?
- Does that mean more light pollution?
- I’ve heard the new LEDs disrupt sleep patterns. Is that accurate?
- Who can I contact for additional information about the LED program?
Street lighting is provided by the City for major, collector and local roads where vehicles, bicycles and pedestrians are generally present.
The City owns about 55,000 street lights, which brighten our streets and parks. Street lights help make travel safer and reduce crime by increasing visibility. The City will switch 45,000 of those street lights to LEDs. The remaining 10,000 are ornamental street lights and we're still in the process of finding LED retrofits and replacements that will work for them. The ornamental street lights provide similar benefits as standard street lights. Many downtown streets and other special lighting districts are lit by ornamental street lights.
Cities around the world are switching to LED (light-emitting diode) lights as a way to save both money and energy, including our neighbors to the north in Seattle and nearby in Gresham, Lake Oswego, Hillsboro, Beaverton, Clackamas County and Milwaukie, to name a few.
LED lights have approximately a 50 percent lower energy consumption to their high-pressure sodium luminaire predecessors. Those lights, most installed in the mid-1980s, are at the end of their useful lives and need replacement. LEDs will provide better service reliability and lower maintenance costs.
The new LEDs have a longer lifespan - about four times that of the bulbs we currently use. That translates to ongoing savings in maintenance costs as result of the extended maintenance cycle for bulb replacement. Less maintenance also means fewer service vehicle trips for repairs and thus reduced carbon emissions.
Over time the program will actually save money - about $1.5 million a year. But to get the program going, in December 2012, the City Council unanimously passed an ordinance dedicating $18.5 million to the conversion project. That money came from a general obligation bond. That’ll be covered – and more – by the eventual savings. Once the project is complete, which is expected to be around December 2016, the City can expect to save $1.5 million a year in maintenance and energy costs.
The new lights should cut our electrical usage by 12 percent – or 20 million kilowatt hours. That’s a huge savings. It’s also important to note that a switch to the LED technology is expected to keep 10,500 tons of climate-changing carbon pollution out of our atmosphere.
Yes, the City will look different once the conversion is complete. The current high-pressure sodium bulbs produce a light that looks almost pink or orange. The new LED lights, however, produce a light that appears cooler and whiter, akin to moonlight. The result is a higher light quality that improves safety because of depth of field and peripheral vision enhancements without distorting color.
The white lights are the most common color temperature for jurisdictions switching to LEDs, including Seattle, Los Angeles and San Jose and they were chosen after extensive studies by those municipalities.
No, these new lights aren’t any brighter. In fact, the City’s lighting standards are dimmer than national standards because we want to keep light levels manageable for residents. That said, the white light they produce does appear cleaner and brighter to the eye and allows colors to seem more natural at night.
With LED technology, there is also an approximately 20% light depreciation over 20 years. LEDs get dimmer over time and don’t burn out at all once like an old light bulb. The other factor in street light brightness is dirt, which builds up over time and also lessens light output.
Actually, once this is all said and done, the skies should appear clearer. The vast majority of the new LEDs are “cobra-head” fixtures. They receive the best ranking – a ‘0’ – when it comes to the amount of up-light they produce. That means less light pollution or sky glow.
No, there’s no evidence that LED street lighting impacts human sleep cycles any differently than the high pressure sodium street lights that have been used for the past 30 years. When considering the effects of light at night, indoor lighting is more of a concern. The quantity of light emitted by street lights is many times lower than that emitted by typical indoor lighting, TVs, tablets or PC screens. That said, we’re always open to public feedback on this process.
Please contact Dan Spoelstra at firstname.lastname@example.org or 503-865-LAMP (5267) for additional information or to leave a comment.