Streetlights

The following requirements apply to all streetlights, regardless of ownership:

• Must be 2700K or less in color temperature (Section 102-4B) (2200K is recommended to be the most dark-sky and neighbor friendly)

• Must be 5000 lumens or less per fixture (or, if on residential property, 1500 lumens or less) (Section 102-4C(3))

• The rating for backlight, uplight, and glare (the "BUG" rating) can't exceed B1-U0-G1 (Section 102-5G(1)) 

• Add-on shields must be added whenever requested by a resident to eliminate light trespass unless they are not commercially available for the type of fixture in question (Section 102-5G(2))

• New or replacement streetlights must have controls that are capable of automatically reducing the lumen output by at least 50% at a programmed time (Section 102-5G(3))

• If the Town proposes a project that involves the retrofit or replacement of streetlights, the Town must undertake a pilot demonstration with multiple options (including 2200K and 2400K fixtures) and solicit public comments before making a final decision on what to purchase and install (Section 102-5G(4)).

• If the Town retrofits a streetlight during the "grace" period for coming into compliance with the bylaw, the streetlight must be brought into compliance with the requirements stated above at the time the work is done (Section 102-2D(1)(c)).

• A streetlight can only be added to address a public safety hazard if the hazard can't be effectively mitigated though some other means, as determined by the Town Manager (Section 102-5H(1).

• If the Town proposes adding more than 10 streetlights, it must seek public comment prior to purchasing and installing them to help mitigate unforeseen negative impacts (Section 102-5H(2)).

Background

The "cobra head" streetlights on the island (the ones on utility poles) are currently owned by National Grid, unlike the shorter, decorative streetlights, which are owned by the Town.

National Grid does not convert the cobra head fixtures to LED unless requested to do so by the Town. Currently, the LED fixtures that National Grid is willing to install do not satisfy the requirements of the new bylaw.

Other towns served by National Grid, including towns on Martha's Vineyard, have purchased the cobra head fixtures from National Grid in order to be able to install LED fixtures that are more dark-sky friendly —which also saves them substantial money in maintenance costs.  

To date, the Town of Nantucket has resisted doing this out of concern for the administrative burden of retaining a contractor on the mainland to handle the installation and ongoing maintenance needs of LED streetlights, notwithstanding the fact that towns on Martha's Vineyard have done this and found it to be manageable.

For an in-depth discussion of all this, read Investigating the Conversion to LED Streetlighting on Nantucket, a WPI student report written in 2021.