Frequently Asked Questions about LED Conversion Program

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Will I notice the new lights?

The new streetlights make colors look bright and more "true' to the natural color. Trees look green instead of brown; a blue car looks blue instead of gray. Because of this improved color rendition, everything appears brighter and sharper under the new streetlights, even when the amount of light is less than the old lights.

The “color temperature” (warm-cool) of the streetlights is 4000K, which is in the middle of the warm-cool range.  This color temperature closely matches moonlight. This color temperature of the new lights is the same or “warmer” than the quarter-of-a-million LED streetlights that have been or are being installed in Boston, New York, Los Angeles, Oakland and San Francisco. The color of the new streetlights is the “warmest” typically available for LED streetlights.

How much savings will the City experience?

The new streetlighting system will consume about 25% of the energy of the existing streetlights, saving the City an estimated $500,000 per year in electricity costs, and allowing us to meet the "carbon footprint" reduction goals that we have set for ourselves.

Can the light levels of the fixtures be adjusted?

A wireless control system has been installed. This allows dimming of the streetlights. When a new streetlight is installed, it will be much brighter than normal until it communicates with the dimming system, which can take a few weeks. Most of the streetlights are already under the control of the dimming system which turns lights on to only 70% of their potential brightness, and later in the evening, dims them even further to about 35% of their brightness. By the time most of us are going to bed, the streetlights will be dimmed to about a third of their current brightness. This dimming system is unique among mid- to large-size cities in the U.S. and reflects the sophisticated approach Cambridge has taken.

What factors were considered in designing the new LED system?

A system of street classification was developed to determine appropriate light levels for each street. Streets were evaluated for width, light pole spacing, and vehicular and pedestrian activity and were assigned to categories corresponding to lighting criteria. These criteria are in accordance with guidelines used by the Federal Highway Administration, MassDOT, and the Illuminating Engineering Society.

Did the City test the new LED lights?

Test installations were conducted on Inman Street and Rindge Avenue in 2010, and on small sections of several others streets in 2013.

How many new lights will be installed

The City of replacing about 7,000 lights (4,900 on street, 2,100 specialty and park fixtures) with energy-efficient LED fixtures.

What is an LED?

It is a Light Emitting Diode.

What is the color temperature of the HPS (High Pressure Sodium) Cobra Head fixtures?

2200K (Kelvin)

What is the color temperature of the new LED fixtures?

4000K (Kelvin)

What was the color temperature of Metal Halide?

4000K (Kelvin)

What is Cambridge using for LED fixtures?

The City has selected a Cree LEDway Streetlight, 40LED, 80LED and 120LED.

Will the new LED lights produce unwanted spill light?

The new lights will reduce unwanted spill light into homes and properties.

Will the public parks be converted to LED?

Yes, this phase of the project is expected to be completed by the end of 2016.

Will the decorative street lights be converted to LED?

Yes, this phase of the project is expected to be completed by the end of 2016.