Outdoor Lighting

Download a Word file of this Bylaw

BYLAW: Outdoor Lighting By-law

MUNICIPALITY: Lexington, Massachusetts

DATE ADOPTED: 1998

FOR MORE INFORMATION ON THIS BYLAW:
Contact Lexington Planning Department, Planning Director,
Phone: (781)862-0500 x 245 Fax: (781)861-2748

PURPOSE OF BYLAW:
Lexington values its aesthetic character and its historical environment. Both of these are potentially threatened by poorly considered or even inadvertent over-lighting.

• A zoning provision that encourages good lighting at the design stage can help prevent over-lighting and excessive glare that actually inhibit good vision.
• Glare and light spill are nuisances that generate complaints. They are appropriate subjects for zoning regulation in Lexington, as they are in many other communities.
• Good outdoor lighting will complement the character of the town.
• Reducing glare will improve visibility for motorists and neighbors.
• Unwanted light spill on adjacent properties and on streets will be minimized.
• The cost and waste of unnecessary energy consumption will be reduced.
• A zoning provision that encourages good lighting will provide good examples and promote voluntary actions by property owners to improve their own lighting installations.

TEXT OF THE BYLAW

RECOMMENDATION

The Planning Board recommends that the proposed amendment be approved.

The Planning Board is proposing a new section in the Zoning By-Law to deal with outdoor lighting. While this may be seen as a new initiative, it builds on provisions already in the Zoning By-Law and is consistent with the purposes of zoning as set forth in State law.

OBJECTIVES

Lexington values its aesthetic character and its historical environment. Both of these are potentially threatened by poorly considered or even inadvertent over-lighting.

1. A zoning provision that encourages good lighting at the design stage can help prevent over-lighting and excessive glare that actually inhibit good vision.

2. Glare and light spill are nuisances that generate complaints. They are appropriate subjects for zoning regulation in Lexington, as they are in many other communities.

3. Good outdoor lighting will complement the character of the town.

4. Reducing glare will improve visibility for motorists and neighbors.

5. Unwanted light spill on adjacent properties and on streets will be minimized.

6. The cost and waste of unnecessary energy consumption will be reduced.

7. A zoning provision that encourages good lighting will provide good examples and promote voluntary actions by property owners to improve their own lighting installations.

WHY NOW?

Progressive communities like Lexington are beginning to address the outdoor lighting issue. Other communities have taken the lead and there are examples of other by-laws to use. The movement toward regulation of lighting has two essential roots:

1. The quality of life - an aesthetic concern about the character of the community

2. Energy conservation and "sustainability" - the efficient use of resources.

An awareness has been developing that increased light levels are more characteristic of urbanized areas while most of our residents would prefer to remain suburban, at the least, or even more rural.

Members of the Selectmen's Lighting Options Committee have assisted the Planning Board in preparing the proposed amendment. There is a better understanding of industry technical standards which have been incorporated into some model By-Laws that communities, like Lexington, can use.

There are already eight scattered references to outdoor lighting in the Zoning By-Law. These references are all phrases such as "excessive level of illumination" or "disturbing, detrimental or hazardous to persons working or living in the neighborhood by reason of .. excessively bright or flashing lights". Interpreting those terms is largely a matter of personal judgement. That type of provision is not characteristic of a good regulation because it provides:
no guidance or direction to an applicant as to what is expected or required,
no standard of review for an appeal - either to the Board of Appeals or to a court.
A Zoning By-Law should provide objectivity by means of measurable standards for outdoor lighting based on industry standards rather than personal judgement. Thus the proposed amendment consolidates scattered references into one comprehensive section and provides objective measurable standards.

In Lexington and in many communities, there are many examples of "bad" lighting - which wastefully lights more area than it needs to resulting in light spill onto adjoining lots or streets. In many cases the "bad" lighting is erected unknowingly.

In preparing this amendment, the Board has relied on an outstanding report, Outdoor Lighting Manual for Vermont Municipalities, published by the Chittendon County Regional Planning Commission. Preparation of this report was funded, in part, by a grant from the Municipal Energy Management Program of the United States Department of Energy. In addition to a wealth of technical information, the report demonstrates how Vermonters are concerned about how outdoor lighting can affect the character of their communities and state.

CHARACTERISTICS OF LIGHTING

The general problems of poor lighting are glare, overlighting, light escalation, skyglow, and energy waste.

Lighting Levels

Lighting problems arise when neighboring areas are illuminated at different levels. The human eye can adapt to only one light level at a time. An area can be adequately lit at a lower level of light. However, if a bright light is introduced on an adjoining area, the eye adjusts to the brightest light level. The formerly adequately lit area can now look dark and shadowy. That starts an escalation process in which light levels are ratcheted up to ever higher levels.

It may be contrary to conventional wisdom but brighter is not always better. Scientific evidence is that even light levels result in the greatest visibility.

Glare

Glare is excessive brightness that makes it difficult to see or causes discomfort. Glare is caused by light fixtures that do not control the light they emit. Instead of simply lighting the surface that needs to be lit, light spills out and shines into the viewer's eyes. The viewer may not be able to see other objects that are necessary to see. Glare is a factor in nighttime accidents in which a driver cannot adequately see other vehicles, pedestrians, cyclists or even poles or trees.

Glare is a particular problem for older persons due to changes in the eye brought about by aging. Older people are reluctant to drive or walk at night because of reduced visibility. With an extraordinarily high percentage of its residents 50 and over, Lexington needs to pay particular attention to glare and poor lighting.

One solution to glare is to use "cut-off" light fixtures that direct light down onto only the surface that needs to be lit. "Cut-off" light fixtures avoid "light spill" onto adjoining properties or streets.

Color

Objects illuminated under different types of lighting appear to be colored differently. Most people are familiar with the yellow-orange hue of objects lit by sodium vapor lights. Trees, shrubs, lawns, people and nearly all other objects appear differently under certain types of lighting.

Lighting standards are expressed in terms of white light. An incandescent bulb most closely corresponds to daylight. The ability of a lamp to show color accurately is known as its color-rendering ability. The industry has a "color rendering index (CRI)".

The color of lighting is more than an aesthetic issue although many are simply dissatisfied with the color of objects lit at night. In a surveillance or criminal situation it may be important to identify vehicles, people's clothing or other objects accurately by their color. Imagine a report of criminal activity under sodium vapor lighting -
The suspect was a yellow-orange male of medium height and build with a yellow-orange complexion. He was wearing a yellow-orange jacket and a yellow-orange hat. He fled the scene driving a yellow-orange Ford.
How soon is this perpetrator likely to be apprehended?

Security, Crime and Exterior Lighting

Specialists in the field of security lighting point out that lighting does not, by itself, prevent crime. This is not to say that lighting is not important because it does play a role in both personal security and protecting property. In terms of visibility, that role is facilitating surveillance - allowing potential criminal acts or perpetrators to be seen. Security lighting should be designed to produce good visibility - through even light at an adequate light level. Lighting that is too bright or glaring can create shadows and prevent good visibility by witnesses. As indicated above, the quality of the light, i.e. its "color rendering index (CRI)" is important.

Regardless of its actual effects on visibility and what the eye can see, an adequate light level is important for a person's sense of security - their psychological well being. It is still possible to have an adequate, and even, level of light that reduces shadows without overlighting.

Security studies show that high lighting levels late at night, when there are no persons to be protected or no potential witnesses to a crime, are not effective. Those studies suggest the property owner would be better advised to invest in other security systems such as motion detectors.

For security reasons, contrary to some popular opinion, the objective should be adequate and even light levels rather than overly bright and inconsistent light levels. That is what Section 14 aims to promote.

Skyglow

"Skyglow" occurs when exterior light, shining into the sky bounces off clouds or dust particles. The light source may be unshielded fixtures or light that reflects off surface materials such as paving, painted walls or snow. "Skyglow" is also referred to as ambient glow or light pollution.

Lexington residents are familiar with the skyglow phenomenon above concentrations of commercial development. The effect of "skyglow" is to change the character of a nighttime space from rural or suburban to urban.

While skyglow cannot be eliminated, it can be reduced by the use of "cut-off" fixtures and reducing lighting levels to only the amount of illumination necessary. Energy is wasted when light is directed where it isn't wanted or when it shines uselessly into the night sky.

WHAT IS, AND IS NOT, REGULATED

The Planning Board has exercised restraint in the scope of the proposed amendment. Outdoor lighting is a new field of Town regulation and needs to be approached in manageable increments. Outdoor lighting is a technical field requiring specialized skills, experience and equipment. The scope of Section 14 can be expanded in future years as Town Meeting thinks necessary.

The proposed amendment will not apply to one and two family dwellings on lots on which they are the principal use. One reason for excluding one and two family houses is to reduce the volume of permit activity until the Inspectional Services Department has more experience with Section 14. Another reason is that a formal lighting plan is required with each application for a building or special permit. Homeowners should be spared the cost of retaining a lighting professional to prepare a lighting plan.

Another type of outdoor lighting that would not be regulated by the proposed amendment is street lighting, lights that control traffic or other lighting for public safety on streets and ways. There are technical issues with street lighting such as the height and type of fixture. Further, this is a complex period for relations between utilities and the Town with the deregulation of electrical service. Finally, while zoning regulates the use of land, the Town may either contract with, or, in time, own the street lighting fixtures. The Town has more effective methods of developing standards specifically tailored to the special characteristics of street lighting than through a zoning regulation.

The proposed amendment does apply to commercial buildings, schools, churches, playgrounds, apartment buildings and parking lots wherever they are located.

Newly adopted regulations may only apply to new construction or installations; they cannot be retroactive. Existing lighting installations will be "grandfathered". However, when an existing outdoor lighting installation is being modified, extended, expanded, or added to, the entire outdoor lighting installation on the lot will be subject to Section 14.

Since no regulation can be written to cover absolutely everything, the amendment includes a provision for the Board of Appeals to grant exceptions to one or more of these regulations by a special permit where special situations can be shown to exist.

PRINCIPAL FEATURES OF THE PROPOSED AMENDMENT

The proposed amendment will require a lighting plan as part of every permit application whenever outdoor lighting is proposed. That will provide the opportunity to review designs while they are still on paper.

Shielding of fixtures is intended to control glare and light trespass. That control will occur in three ways:
Require that any fixture above a certain threshold of brightness be shielded so that none of its light shines above a horizontal plane.
Require that all fixtures, regardless of brightness, be shielded to prevent glare and light spill on adjacent properties.
Permit upward-shining floodlighting, but require shielding to limit the light to the thing being lit.

The quality and color of lighting will be improved by provisions that:
Eliminate the worst light sources. Examples are: Low-pressure sodium and non color-corrected mercury vapor lamps. These give the poorest outdoor visibility.
Introduce the concept of CRI (color rendering index) as an objective standard. Lamp technology is changing fast, and acceptable choices with efficiencies, comparable to these older types of poor light, are increasingly available.

Hours of Operation
The use of lighting will be limited after 11:00 p.m. That will eliminate all-night lighting with the exception of low level security lighting where necessary. Other exceptions to the 11:00 p.m. limit is that if the use is being operated, such as a business open to customers, or where employees are working, or where an institution is conducting an activity, normal illumination will be allowed during the activity and for not more than one half hour after the activity ceases. For example, if Town Meeting runs late, it should not have to go home in the dark.

THE ZONING BASIS FOR THE REGULATION OF OUTDOOR LIGHTING

Including a section regulating outdoor lighting in the Zoning By-Law is well justified by the purposes of zoning as set forth in Chapter 808 of the Acts of 1975 and long accepted in Massachusetts. Regulating outdoor lighting is based on the initial justification for zoning in the 1920s - the regulation of nuisances. Glare and excessive levels of lighting are nuisances. The use of the power of government regulation - through zoning - has provided a general system of reducing nuisances that is a widely accepted alternative to resolving disputes between private property owners in the courts.

Regulating outdoor lighting is based on another purpose of zoning - promoting the general welfare. The following are some of the objectives cited in The Zoning Act, the State law that defines the purposes of zoning, that apply to the regulation of outdoor lighting:
to secure safety from . other dangers,
the prevention of blight and pollution of the environment,
to preserve and increase amenities by the promulgation of regulations,
the development of the . scenic and aesthetic qualities of the community.

The proposed amendment lists as its purposes:
enhance public safety and welfare by providing for adequate and appropriate outdoor lighting,
provide for lighting that will complement the character of the town,
reduce glare,
minimize light trespass, and
reduce the cost and waste of unnecessary energy consumption.

PUBLIC HEARING

A duly advertised public hearing was held on February 23, 1998. Comments from the audience were very positive. Some want the By-Law to apply to nuisance residential lights as well as streetlights and think it should be retroactive. Other comments included: The color of the light is also very important. Some colors are more penetrating. Specificity in the By-Law as to units of measure of lighting is a very important issue for enforcement. Safety should be emphasized as a goal because bright lights can blind drivers at night.

Myla Kabat-Zinn, the Lighting Options Committee Chairman, said that the Committee is working with the Director of the Public Works Department to choose suitable street lighting fixtures for the Town. She said that the process of choosing fixtures is very complex.

MOTION

[This motion was not printed in the Warrant due to its length and is revised somewhat from
the draft available at the public hearing.]


SECTION 14. OUTDOOR LIGHTING

14.1 OBJECTIVES

The regulation of outdoor lighting is intended to:
enhance public safety and welfare by providing for adequate and appropriate outdoor lighting,
provide for lighting that will complement the character of the town,
reduce glare,
minimize light trespass, and
reduce the cost and waste of unnecessary energy consumption.

14.2 APPLICABILITY, TERMINOLOGY

The requirements of this section shall apply to outdoor lighting on lots and parcels in all districts but shall not apply to:
one and two family dwellings on lots on which they are the principal use, or
street lighting, lights that control traffic or other lighting for public safety on streets and ways.
When an existing outdoor lighting installation is being modified, extended, expanded, or added to, the entire outdoor lighting installation on the lot shall be subject to the requirements of this section.

14.2.2 TERMINOLOGY

In addition to the terms defined in Section 2, Definitions, of this By-Law, the following words, which are technical terms applying to lighting, which are set forth below, shall have the meaning indicated below. Although set forth here for convenience, the terms shall have the same effect as if set forth in Section 2, Definitions.

COLOR RENDERING INDEX (CRI): A measurement of the amount of color shift that objects undergo when lighted by a light source as compared with the color of those same objects when seen under a reference light source of comparable color temperature. CRI values generally range from 0 to 100, where 100 represents incandescent light.

CUTOFF ANGLE: The angle formed by a line drawn from the direction of the direct light rays at the light source with respect to the vertical, beyond which no direct light is emitted.

DIRECT LIGHT: Light emitted from the lamp, off the reflector or reflector diffuser, or through the refractor or diffuser lens, of a luminaire.

FIXTURE: The assembly that houses a lamp or lamps, and which may include a housing, a mounting bracket or pole socket, a lamp holder, a ballast, a reflector or mirror, and/or a refractor, lens, or diffuser lens.

FULLY-SHIELDED LUMINAIRE: A lamp and fixture assembly designed with a cutoff angle of 90º, so that no direct light is emitted above a horizontal plane.

GLARE: Light emitted from a luminaire with an intensity great enough to produce annoyance, discomfort, or a reduction in a viewer's ability to see.

HEIGHT OF LUMINAIRE: The vertical distance from the finished grade of the ground directly below to the lowest direct light emitting part of the luminaire.

INDIRECT LIGHT: Direct light that has been reflected off other surfaces not part of the luminaire.

LAMP: The component of a luminaire that produces the actual light.

LIGHT TRESPASS: The shining of direct light produced by a luminaire beyond the boundaries of the lot or parcel on which it is located.

LUMEN: A measure of light energy generated by a light source. One foot candle is one lumen per square foot. For purposes of this By-Law, the lumen output shall be the initial lumen output of a lamp, as rated by the manufacturer.

LUMINAIRE: A complete lighting system, including a lamp or lamps and a fixture.


14.3 LIGHTING PLAN

Wherever outside lighting is proposed, every application for a building permit, a special permit, a special permit with site plan review, a variance, or an electrical permit, shall be accompanied by a lighting plan which shall show:
the location and type of any outdoor lighting luminaires, including the height of the luminaire;
the luminaire manufacturer's specification data, including lumen output and photometric data showing cutoff angles;
the type of lamp such as: metal halide, compact fluorescent, high pressure sodium;
a photometric plan showing the intensity of illumination at ground level, expressed in foot candles; and
that light trespass onto any street or abutting lot will not occur. This may be demonstrated by manufacturer's data, cross section drawings, or other means.

14.4 CONTROL OF GLARE AND LIGHT TRESPASS

14.4.1 Any luminaire with a lamp or lamps rated at a total of more than 2,000 lumens shall be of fully shielded design and shall not emit any direct light above a horizontal plane passing through the lowest part of the light emitting luminaire.

14.4.2 All luminaires, regardless of lumen rating, shall be equipped with whatever additional shielding, lenses, or cutoff devices are required to eliminate light trespass onto any street or abutting lot or parcel and to eliminate glare perceptible to persons on any street or abutting lot or parcel.

14.4.3 Paragraph 14.4.1, above, shall not apply to any luminaire intended solely to illuminate any freestanding sign or the walls of any building but such luminaire shall be shielded so that its direct light is confined to the surface of such sign or building.


14.5 LAMPS

14.5.1 Lamp types shall be selected for optimum color rendering as measured by their color rendering index (CRI), as listed by the lamp manufacturer. Lamps with a color rendering index lower than 50 are not permitted. This paragraph shall not apply to temporary decorative lighting which may include colored lamps, such as holiday lighting.


14.6 HOURS OF OPERATION

14.6.1 Outdoor lighting shall not be illuminated between 11:00 p.m. and 6:00 a.m. with the following exceptions:
if the use is being operated, such as a business open to customers, or where employees are working or where an institution or place of public assembly is conducting an activity, normal illumination shall be allowed during the activity and for not more than one half hour after the activity ceases;
low level lighting sufficient for the security of persons or property on the lot may be in operation between 11:00 p.m. and 6:00 am, provided the average illumination on the ground or on any vertical surface is not greater than 0.5 foot candles.


14.7 SPECIAL PERMITS

In accordance with Section 3, the Board of Appeals, acting as the special permit granting authority, may grant a special permit modifying the requirements of this Section, provided it determines that such modification is consistent with the objectives set forth in paragraph 14.1, in the following cases:
where an applicant can demonstrate, by means of a history of vandalism or other objective
means, that an extraordinary need for security exists.
where an applicant can show that conditions hazardous to the public, such as steep embankments or stairs, may exist in traveled ways or areas.
where a minor change is proposed to an existing non-conforming lighting installation, such that it would be unreasonable to require replacement of the entire installation.
where it can be demonstrated that for reasons of the geometry of a lot, building, or structure, complete shielding of direct light is technically infeasible.

In Section 2, DEFINITIONS, by adding the following in the proper place in the alphabetical order:

"COLOR RENDERING INDEX (CRI): (See Section 14, Outdoor Lighting, for definition.)
CUTOFF ANGLE: CUTOFF ANGLE: (See Section 14, Outdoor Lighting, for definition.)
DIRECT LIGHT: (See Section 14, Outdoor Lighting, for definition.)
FIXTURE: (See Section 14, Outdoor Lighting, for definition.)
FULLY-SHIELDED LUMINAIRE: (See Section 14, Outdoor Lighting, for definition.)
GLARE: (See Section 14, Outdoor Lighting, for definition.)
HEIGHT OF LUMINAIRE: (See Section 14, Outdoor Lighting, for definition.)
INDIRECT LIGHT: (See Section 14, Outdoor Lighting, for definition.)
LAMP: (See Section 14, Outdoor Lighting, for definition.)
LIGHT TRESPASS: (See Section 14, Outdoor Lighting, for definition.)
LUMEN: (See Section 14, Outdoor Lighting, for definition.)
LUMINAIRE: (See Section 14, Outdoor Lighting, for definition.)"

In subparagraph 3.3.2.e.1 by adding the phrase "(See Section 14, Outdoor Lighting)" after the phrase "level of illumination";

In subparagraph 3.3.3.g by adding the phrase "(See Section 14, Outdoor Lighting)" after the word "illumination";

In subparagraph 3.4.2.g by adding the phrase "(See Section 14, Outdoor Lighting)" after the phrase "level of illumination";

In subsection 5.7, in the third paragraph, by adding the phrase "(See Section 14, Outdoor Lighting)" after the word "lighting";

In subparagraph 5.8.1 by striking out the existing subparagraph "b. Any nighttime illumination shall be installed in such a way so as not to shine directly into nearby housing.", and by redesignating subparagraphs 5.8.1.c, 5.8.1.d and 5.8.1.e and all cross references thereto to be 5.8.1.b, 5.8.1.c and 5.8.1.d respectively;

In subparagraph 11.2.1.b by adding the phrase "(See Section 14, Outdoor Lighting)" after the word "lighting";

In subparagraph 11.6.6 by striking out the existing subparagraph "d. All artificial lighting used to illuminate specifically any parking space, loading bay, maneuvering space or driveway shall be so arranged that all direct rays from such lighting fall entirely within the parking or loading area and shall be shielded so as not to shine upon abutting properties or streets. The level of illumination of lighting for parking and loading areas shall be low so as to reduce the glow of ambient lighting perceptible at nearby properties or streets.";

In paragraph 13.2.5, Illumination, in the first line by striking out the phrase "12:00 midnight" and by inserting in place thereof: "11:00 p.m.".