Thursday, July 24, 2014

City to spotlight results of street light experiments

From page A1 | June 22, 2014 |

Learn more

What: Davis City Council meeting

When: 6:30 p.m. Tuesday

Where: Community Chambers at City Hall, 23 Russell Blvd.

Watch it live: Comcast Channel 16, AT&T U-Verse Channel 99 or on the city’s website at

City staff will shed light on the paused residential street light replacement project Tuesday night, giving the Davis City Council a series of options to consider before it flips the switch and green-lights the effort again.

Since last month — when the council ordered a pause in the replacement of half of the city’s roughly 1,300 street lights for residential areas after dozens of complaints about glare surfaced — city staff have gone deep in the tank with the help of the UC Davis California Lighting and Technology Center to experiment with ways of reducing glare and studying the effects of different colored lights.

Herb Niederberger, general manager of utilities, and Mitch Sears, sustainability program manager, have revealed the results of those experiments and have established a matrix the council could look at Tuesday night and choose the best path for the city to take as it completes installation of brighter LED lights.

UCD’s lighting center has been a boon to the city, the pair said in their report.

“As subject-matter experts operating from a public service mission basis, staff places higher weight on CLTC assessments than its own assessments or those of industry representatives or advocates,” the report said.

Two focuses of the CTLC have been on light shields and dimmed lights. Tests found that light shields did reduce stray light into residents’ yards, which city staff deemed “a good step forward.”

“In addition, staff perceived a significant reduction in glare and light spill side to side and backward from installation of the shields,” the report said. “However, glare and light spill across the street did not change and there was less light projected up and down the street due to sharper cut-off of the shield.”

A controlled experiment of dimmed lights was conducted on the evening of June 12 on Oyster Bay Avenue in West Davis, with 15 percent dimmed lights and 25 percent dimmed lights. The former showed no glare reduction and the latter showed only slight glare reduction. In all, there was little difference between the dimmed lights and the full standard LED lights.

Whether the council picks dimmed or shielded lights, city officials believe safety is not an issue with the new LED lights, despite past comments from the public who are worried about criminals more easily hiding in the shadows.

“Bicycle, pedestrian and general safety is assumed to improve under all options due primarily to more consistent lighting across the community,” the report said.

The solutions could cost the city anywhere from $33,000 to $150,000 out of the known variable costs.

The total $1.172 million cost of the project across all city streets will be paid for over a period of six years by $200,000 in energy and labor cost savings annually.

— Reach Dave Ryan at or 530-747-8057. Follow him on Twitter at @davewritesnews.






Discussion | 4 comments

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  • anonymous?June 22, 2014 - 11:45 am

    Oh my god, "UC Davis California Lighting and Technology Center"... I'd looooove to hear those consultation meetings. You need to make the new lights look like the old ones, so the people's brains won't be so disturbed by the change, gel the lights to the same color temperature and luminosity as the old ones. There is really zero reason that new, can't look exactly the same. The only reason I can imagine they'd go the route that they did is that it's cheaper and the complaints who'd be temporary as people's brains are inherently malleable and will get used to it.

    Reply | Report abusive comment
  • BolenJune 22, 2014 - 6:19 pm

    Why would the City Council pick "dimmed or shielded lights" given neither solves the problem of glare or light emitting too far?

    Reply | Report abusive comment
  • DanJune 22, 2014 - 6:55 pm

    New LED street lighting was installed on our Davis street about two months ago. We have one at the corner of our lot. Glare from these lights comes from looking at them at night and yes, they are even more uncomfortable to look at than the lights they replaced. These LEDs produce a bright white light that looks better to my eyes than the surreal iodine pink from the older halogen bulbs. The coverage pattern affects the same portion of our front yard (most of it). Looking at these new street light housings I see slots intended for mounting a shade or visor. Given my choice I would much rather see shades that limit light to street and sidewalk areas keeping light spill off my property entirely. Shades may also help to reduce light pollution of the night sky.

    Reply | Report abusive comment
  • Barbara clowersJuly 13, 2014 - 5:24 pm

    Last night was a super moon but it was no match for the new street lights.

    Reply | Report abusive comment
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