Davis, CA LED Streetlight Retrofit

Davis, CA LED Streetlight Retrofit

Project Overview: The City of Davis is located in Northern California and has a population of approximately 66,000 is home to the University of California at Davis. In January of 2014, the Davis city council approved plans to upgrade 2,600 90-watt HPS cobra-style streetlights to LED fixtures. The city was motivated by plans to save approximately $150,000 annually in energy and maintenance costs, reduced CO2, and improved safety. The city owns the streetlights, but maintenance is provided by PG&E as part of its tariff. Davis entered into an energy service company (ESCO) agreement with Siemens to fund the project from the energy savings.

The city conducted a pilot test with two types of LED fixtures: one with 2115 lumens and 4,000K CCT and the other 2326 lumens and 5,700K CCT. Based on the feedback from the test, the city made the decision to use Leotek 27-watt/2,800 lumens fixtures with 4,000K CCT color temperature.

Installation of the new LED streetlights began in January of 2014. By May, negative public reaction to the conversion project precipitated a review by the city council, which voted to put the project on hold pending an investigation to determine how best to proceed. The city received 40 comments by residents of which 36 or 90% were negative. The complaints were focused on the new fixtures being too bright, producing too much glare and light trespass, increasing skyglow and light pollution, and resulting in potential negative impact on human health and wildlife. When the project was put on hold, 1,400 of the new LED fixtures had already been installed.

After the city staff reviewed of available options, it was determined that the 4,000K CCT color temperature and the perceived increased brightness of fixtures were the primary causes of the negative public reaction. Several remedial actions were considered, but ultimately in October 2014, the decision was made to replace 650 of the already installed fixtures in residential areas and all remaining LED fixtures with Leotek 19-watt Green Cobra Jr., producing approximately 1800 lumens and 2,700K CCT. In addition, the installation would increase the number of house-side shields to reduce glare and light trespass. Approximately 750 of the 4000K fixtures in non-residential areas were left in place.

The approximate cost of the modification was $325,000, which included losses by the contractor due to the delay, additional labor and the new fixtures.

The installation was resumed in July of 2015 and completed by late summer. Davis is now planning phase two of the LED conversion; it will replace approximately 1,800 decorative fixtures in park and greenbelt areas using the same 2,700K CCT color temperature.

Analysis: The City of Davis took the important step of installing a pilot test of the new LED fixtures, but unfortunately did not actively engage broad public feedback to accurately ascertain their opinion until after the process began. For any survey of public preferences to be effective, an organized program to solicit input from a broad cross-section of the public must be undertaken prior to implementation. Ideally a lighting consultant should be engaged to develop survey questions and coordinate a guided tour of the installation. In addition to viewing the various fixtures being considered, the public tour should demonstrate the lighting at a variety of illumination levels. Fixture types should be selected to include color temperature options starting at 2,700K CCT for all residential installations, and dimming should be demonstrated and the public should be asked if it should be used.

The city also engaged the California Lighting Technology Center (CLTC) for assistance with the project. CLTC has also collaborated on a pilot test of motion sensitive adaptive controls for potential adoption in the future.

In conclusion, the City of Davis should be commended for listening to the residents once the installation was started and for having the courage to remedy the problems that were communicated.

Links for further reading:

http://cityofdavis.org/city-hall/public-works/transportation/current-projects/city-wide-streetlight-led-retrofit-project

http://eec.ucdavis.edu/files/2012_State_of_Street_Lighting_in_CA_Final_Report.pdf

News reports

http://www.davisvanguard.org/2014/05/the-citys-streetlight-retrofit-project-draws-complaints/
http://www.kcra.com/news/davis-asks-residents-to-rank-new-led-street-lights/27600602
http://sacramento.cbslocal.com/2014/10/21/davis-will-spend-350000-to-replace-led-lights-after-neighbor-complaints/
http://www.davisenterprise.com/local-news/let-there-be-light-replacement-program-could-resume/

Related documents:

City Council Reports

9 thoughts on “Davis, CA LED Streetlight Retrofit

  1. I ended up reading this article after reading another article by “Bugs” Stevens regarding AMA recommendations for LED lighting in public.
    I am a lighting professional who works in the entertainment area. Color Temperature and control of the area of lighting are critical. There are very little facts about what people are saying “glare” is in either article. It would seem that many of the complaints are due to the design of the fixture not the source light. I am always amazed at how poorly the spread of the light is controlled in street fixtures historically. My guess is that LED is not the real problem but the design of the new fixture could be the real problem. Mercury vapor lighting is still heavily used and it’s spectrum is severely blue, it’s source is a very sharp point. Sodium vapor is featured in the article and it’s spectrum is severely yellow (and not a yellow found in nature), also with a very sharp pointed source. What are the AMA warnings regarding those lights? Similar to the AMA recommendation, I like lighting between 2,600 and 3,000 k, it is the most comfortable for my eyes. However there can be a quality difference in LED output from different manufactures even for the same overall color temperature, like fluorescent lights it is a “continuous spectrum” issue and it isn’t a simple issue. I found this article and the one by Dr. Stevens to be confusing and potentially alarmist for little reason, I am not sure of the health issue involved. Someone or some group needs to address the lighting fixture design if “glare” and light pollution are to be reduced.

    1. DJ,

      LED fixture design is often an aggravating factor as the individual LEDs are extremely bright and not diffused. This accentuates the glare even when the fixture is fully shielded. However the higher color temperature increase the perception of glare due to the physiology of the eye. In the past manufacturers pushed high CCT because it was the only thing that was competitive with HPS in efficacy. This is no longer the case and CREE and GE now produce 3000K CCT versions of their street lights that have equivalent efficacy. 2700K is typically seen as much more visually comfortable and preserves the ambiance of the neighborhood. DOT planners need to start designing public lighting for their customers and choose fixtures that are glare free, efficient and visually comfortable.

      1. Bob.
        Well Said from across the pond.
        and don’t forget the big drop in blue to surrounding fauna.
        When the Mercury was installed we could plead ignorance to blue light issues that is no longer the case

    2. Agree with DJ completely. The article seemingly tries to blame LED technology when the real problem is elsewhere. Zero mention of the safety/security impact and no mention of improved optical control of the lumens. I really wish they would have consulted with someone who actually knew a few things about lighting.

  2. I think the AMA’s announcement is very accurate.
    They say “Led street light CCT bellow 3000K is not quite enough to be sure that blue light is minimized. The actual spectral irradiance of the LED — the relative amounts of each of the colors produced — should be considered, as well.”
    White Led light is made from blue Led chip filtered by yellow phosphor cover. However, the phosphor cover can not filter the blue light 100%. Therefore, even the 3000K Led has quite a lot of blue light content.
    However, the high blue light spectrum makes makes efficient. according to DoE, 6500K and 3000K has more than 20% efficacy different. If you lower the CCT, the return of investment will be longer.
    Eric Spiegel, the CEO of Siemens, said ” LED may not be the cost effective in reducing energy usage “.

    It is not only AMA, but also the Public Health England recomends to use Led CCT lower than 3000K.

  3. “The city conducted a pilot test with two types of LED fixtures: one with 2115 lumens and 4,000K CCT and the other 2326 lumens and 5,700K CCT. Based on the feedback from the test, the city made the decision to use Leotek 27-watt/2,800 lumens fixtures with 4,000K CCT color temperature.”

    More like: not based on the feedback. That’s like asking if somebody prefers apples or oranges and when they pick apples you give them a cranberry and say “well, it’s red too”.

  4. Since the glare issue is not addressed by DOE recommended specs there will continue to be conflict as these poor lamps are installed. For many municipalities the DOE SSL street lighting recommendation of 4100K is required to get money from the state. The BUG standard ostensibly meant to address glare only addresses light directionality. Very good LED lamps are possible, but are not encouraged by the DOE. Very sad state of affairs.

  5. TOTALMENTE IN ACCORDO CON IL RITORNO A LUCI MENO ABBAGLIANTI E PIU’ “CALDE” . UN PLAUSO AI CITTADINI PER ESSERSI FATTI SENTIRE E PER CHI LI AMMINISTRA PER AVER ASCOLTATO I LORO DISAGI. TALE ESEMPIO DOVREBBE ESSERE SEGUITO DA TUTTI GLI ALTRI. I LED FANNO LUCE MA NON “ILLUMINANO”, ABBAGLIANO, CREA LUCE INNATURALE CHE PROVOCA DISAGIO (OLTRE A CAUSARE MALATTIE); A 4000 K POI RENDE GLI ABIENTI TOTALMENTE INVIVIBILI. QUANDO CE NE RENDEREMO CONTO???????

    Rough English Translation: FULLY IN AGREEMENT WITH RETURN TO LESS HIGH BEAM LIGHTS AND MORE ‘”HOT”. AN APPROVAL TO CITIZENS FOR HAVING MADE THEM FEEL AND WHO MANAGES TO HAVE HEARD THEIR PROBLEMS. EXAMPLE THAT SHOULD BE FOLLOWED BY ALL OTHERS. The LED LIGHT BUT DO NOT “LIGHT”, DAZZLE, CREATE LIGHT unnatural CAUSING DISCOMFORT (WELL AS CAUSE DISEASES); A 4000 K THEN MAKES THE TOTALLY ABIENTI unlivable. WHEN THERE WE WILL ACCOUNT ???????

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