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.
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