Ensure that new development is planned, designed, and constructed
in a manner that integrates sustainable design from the very beginning
so that efforts to generate energy on-site, promote energy efficiency,
and eliminate harmful materials are considered along with the functional
design to achieve high levels of health, energy, and resilience performance;
Establish best practices through the implementation of low-impact
development (LID), SITES, and other measures to create a site that
contributes to rather than degrades the functioning of surrounding
natural systems and the environment;
Establish concepts for projects to incorporate as minimum standards
that will guide a project through the permitting process while allowing
for flexibility in design;
Minimize new impervious surface and encourage restoration of previous
development to natural conditions in sensitive areas, and direct new
development towards disturbed land and brownfields;
Create vibrant walkable public and private spaces with complete streets
that give pedestrians, bicyclist, and transit users equal opportunities
to motor vehicles; and
Include design standards to be used by the Planning Board in its
review and consideration of development proposals to create a visually
pleasing design image for the development as a whole.
Criteria using "shall" are minimum requirements, which the Planning
Board expects applicants to exceed. When compliance is not proposed,
the applicant shall provide a written statement to request a waiver
under §§ 176-3.4 and 176-9.1.6 with an explanation
as to why compliance is not proposed.
Projects shall comply with all provisions of the General Bylaws, the Zoning Bylaw (Chapter 135 of the Code of Lexington), and other applicable regulations, as may be amended.
Land Disturbance. The site and building design shall preserve natural
topography outside the development footprint to reduce unnecessary
land disturbance and preserve natural drainage.
All vegetation to be retained shall be surrounded by temporary protective
fencing or other measures during clearing and construction activities
before any clearing or grading occurs and be maintained until all
construction work is completed and the site is cleaned up.
Priority shall be given to preserving existing stands of mature trees,
trees at the site perimeter, vegetation contiguous with adjacent sites
(particularly existing sites protected through conservation restrictions
or public ownership), and exemplary mature and specimen native trees
in good health and true to species habit and form.
To minimize the clearing and grading on a site associated with construction
activities, such as parking of construction vehicles, offices, trailers,
and stockpiling of equipment and materials, such activities shall
be limited to areas already planned for permanent structures. Topsoil
may not be stockpiled in areas of protected trees and wetlands or
their vegetated buffers.
Development envelopes for structures, driveways, wastewater disposal,
lawn areas, and utility work shall be designated in order to limit
clearing and grading.
The clearing of vegetation and alteration of topography is strongly
discouraged. Where required, the disturbed area shall be revegetated
with a stratified planting of native plant material.
Finished Grade. Finished grades in disturbed areas shall be limited
to no greater than a 3:1 slope (rise over run) while preserving, matching,
or blending with the natural contours and undulations of the land
to the greatest extent possible. The finished grade shall be no higher
than the trunk flares of trees to be retained unless tree wells are
used.
Proper revegetation techniques shall be employed during construction
using native plant species, proper seedbed preparation, fertilizer,
and mulching to protect germinating plants.
Proposed temporary (during construction, such as seeding of loam
piles) landscaping shall include native and drought-tolerant species
and not include invasive or nonnative plants.
Soil stripped from the property shall be stockpiled and reused on-site
where possible. Temporary stockpiles shall be seeded or covered and
protected with erosion controls around the pile base until such soils
are needed.
When new fill is required to be brought onto the site, only clean
fill shall be used. Before fill is brought onto the site, the applicant
shall provide a written notice to the Planning Office, Department
of Public Works (DPW), and the Conservation Commission that includes
the name of the company, the specific location where the fill is coming
from, the type of fill, and any additional information to certify
that all fill is clean.
Sensitive Areas. When any work is located within a wetland buffer
or wetland area, the Conservation Commission will review construction
staging and all associated construction work.
Erosion control and construction best management practices (BMP)
installations shall be checked before the start of construction and
at the end of construction daily. Such controls, when damaged, shall
be repaired within 24 hours.
Noise. Where a project is located within or adjacent to a residential
neighborhood or directly abuts a property with residential use, the
Planning Board may impose limited construction hours.
Access to the site from a public way shall be clearly visible and
easily accessible for all modes of transportation, without visual
interferences (overgrown landscaping, signage, etc.).
Adequate sight lines shall be provided and maintained for pedestrians,
bicyclists, and motorists at all entrance and exit locations. At a
minimum, sight distances shall meet the Massachusetts Department of
Transportation standards for safe stopping and intersection sight
distances.
All projects adjacent to existing sidewalks and walking paths shall
provide pedestrian connections on the property for the benefit of
the users of the property; when a bikeway adjoins the property, adequate
connections for bicyclists shall also be provided.
Where vehicular access drives cross pedestrian routes or sidewalks,
the pedestrian crossings shall be marked and differentiated with variations
in paving materials (for example, by using stamped concrete or asphalt).
Where appropriate, projects should be designed to consider future
public access and possible future connections with adjoining properties
to develop Lexington's pedestrian and bicycle network consistent with
but not limited to the Town-wide Bicycle and Pedestrian Plan and the
2022 Lexington NEXT Comprehensive Plan.
Commercial and mixed-use residential developments and residential
developments with over 40 dwelling units shall provide multimodal
directional signs or markings to guide pedestrians and bicyclists
safely to, from, and through the site.
If separate service, delivery, or loading access is required for
site operations, it shall be distinct and distinguished from other
forms of site access. Access from side streets is preferred.
The number of service, delivery, or loading bays shall be designed
to meet current demands. Where expansion may be necessary, the site
shall be designed with reserved space rather than constructing additional
service, delivery, or loading platforms/bays or areas that are not
presently needed.
Dumpsters shall be located in low visibility areas such as within
or behind buildings. All dumpsters shall have a lid, be located on
an impervious surface with proper drainage, and be screened with a
gated solid enclosure. Chain-link fencing is prohibited. All dumpster
areas shall include separate trash and recycling receptacles.
In addition to bicycle parking, residential developments shall have
both short-term parking areas and covered long-term parking areas
for devices such as scooters and strollers.
Where there are residential units, there shall be space for 1.5 long-term
bicycle spaces per dwelling unit and 0.1 short-term bicycle space
per dwelling unit, with a minimum of two spaces.
Short-term bicycle racks shall be located near main entrances, be
visible (where possible) from a public way, and be at least two feet
from any wall or other obstruction.
Parking shall not require lifting bicycles off the floor or carrying
bicycles up or down stairs, whether indoors or outdoors. Accessibility
standards must be met, including maximum slope of ramps and access
widths leading to bicycle parking areas.
Internal circulation shall be planned to accommodate existing or
planned transportation demand management services, such as public
transit, ride-sharing, and shuttle services.
The site shall be designed to assure safe interior circulation. Pedestrian
ways, bikeways, and vehicular traffic shall be separated physically
and visually with paint or the use of different materials.
Public Transportation. Projects shall be accessible for shuttles
and public transportation to promote alternative transportation options.
Projects near a bus stop are encouraged to provide a bench and shelter.
Pedestrianways and shared-use paths that are accessible, inviting,
safe, and efficiently connect public sidewalks and other pathways,
building entries, parking areas, and outdoor amenity spaces shall
be provided. Pedestrianways shall be at least four feet in width.
The Board may impose a width greater than five feet for shared use
paths.
Outdoor spaces, sidewalks, and pathways should be shaded with trees,
umbrellas, awnings or other similar features. Shading with canopy
solar energy systems is encouraged.
Footpaths and Trails. The Board encourages the creation of footpaths
and trails to offer public access to open land and common open space
within the development and to connect to other nearby open space,
recreational areas, streets, bicycle paths, or other recreational
areas at adjoining land for passive recreation. The applicant may
provide a public easement if the trail network can benefit the neighborhood
and surrounding area.
Except where lack of agreement, physical constraints, site configuration,
or safety considerations preclude strict compliance, off-street parking
shall be accessible by driveways to the parking lots of similar adjacent
uses.
Surface parking shall be conveniently located near the entries of
structures while maintaining the pedestrian safety, attractiveness,
and aesthetics of the site.
Parking shall be subordinate in design and location to the principal
building facade. Surface parking should be located to the side or
rear of a principal building or occupiable structure. Parking in front
of principal buildings and near streets should be limited to accessible
spaces or short-term parking.
Where the top level of a structured parking garage is unroofed, canopy
solar energy systems and water retention (green, blue, greywater)
devices are encouraged.
If visible from a street, the ground floor of parking structures
shall create visual interest using landscaping, architectural screening,
and pedestrian entrances.
Nonresidential uses shall be ready for occupancy and have complete
core and shell ready for tenant fit-out prior to occupancy of the
residential portion of a mixed-use development. The Board prefers
occupancy of commercial and retail space prior to or concurrent with
the residential portion.
Any utility penthouses shall be designed to be compatible with the
aesthetic and material design of the building, minimize interference
with any solar and green roofs, and be centered on the building.
New structures and additions shall minimize the negative impacts
of shadows on adjacent properties or public spaces. The Board may
request repositioning of buildings, upper-story stepbacks, adjustment
in the massing or similar design changes to limit shadow impacts.
Building massing shall be designed to reduce the overall perceived
scale and provide simple and evocative forms that reinforce the theme
of the area and a sense of a human-scaled environment.
New buildings shall reveal different aspects of themselves from different
distances and vantage points through articulation and modulation of
vertical and horizontal components.
Structures located closer to established residential areas shall
consider tapering down the mass of a structure to provide a more compatible
character transition.
Street-facing facades at ground level should be located at the minimum
setback to reinforce the street line. When buildings are set back,
the area between the facade and the street should be designed for
pedestrian use, such as outdoor seating, dining, public art, or other
similar gathering space.
The Board may request modifications in setbacks, physical or material
breaks, building layout, stepbacks, and facade treatments to establish
visual relief.
Envelopes of structures should be physically durable and utilize
high-quality, energy-efficient, easily repaired, and sustainable materials.
The use of natural materials, such as wood, glass, and stone, is recommended
for the first floors of public-facing facades.
All facades visible from a public pedestrianway, such as the Minuteman
Bikeway, shall be given the same architectural detail as the front
facade in terms of entries, fenestration, and materials.
New buildings should be positioned to have their principal facade
and entrance facing the principal street. Multiple buildings on a
lot in a campus-style development may be oriented around an internal
street network or around a community courtyard area to create private
and public space.
Where publicly oriented ground floor commercial uses are present,
retractable storefront windows and moveable facades that open shall
be considered to allow internal uses to visually spill out onto the
sidewalks, activating them and enhancing the pedestrian experience.
A majority of a commercial ground floor's front facade facing a public
way should be transparent glass with views into the space to help
activate street fronts for mixed use developments with first floor
nonresidential uses.
Projecting bays, recesses, cornices, canopies, setbacks, and window
detailing, balconies, and other similar facade elements are encouraged
to add depth. Blank facades along a public way are not permitted.
Entries should be clearly articulated with canopies or recesses and
situated to activate the street front and pedestrian spaces. Nonresidential
entries shall be visible from a public way, or the interior courtyard
or primary access point.
New buildings should break up vertical and horizontal building lines
to reduce the overall massing appearance. This can be achieved through
variations in depth, materials and architectural elements.
All projects should demonstrate to the greatest extent feasible the
utilization of the low-impact development (LID) and SITES, best management
landscape design, and green site design features to reduce adverse
impacts to the environment and public while aiding in the mitigation
and management of stormwater, site design that manages and protects
natural constraints, thermal pollution, and nonpoint and point source
pollution.
At the time of planting, proposed deciduous trees shall be a minimum
of three-inch caliper, measured four feet from ground level, and nondeciduous
trees should be six to eight feet in height when planted.
Gardens of all types, such as community gardens, contemplative gardens,
roof gardens, courtyard gardens, vertical gardens, edible gardens,
rain gardens, etc., are encouraged to promote community engagement,
health and well-being, physical activity, and mental restoration.
Projects that involve disturbance of more than one-half acre of land
area should be designed to be certifiable at the gold level under
SITES v2, as amended.
Projects should locate buildings, impervious surfaces, and general
development to retain specimen trees and mature trees with a DBH of
12 inches or greater measured 4 1/2 feet from the base.
Plants listed as "invasive" by the Massachusetts Invasive Plant Advisory
Group and plants on the Massachusetts Prohibited Plan list are strictly
prohibited.
Plant and tree selection should consider possible pollutants, water
management, habitat for pollinator species and other wildlife, and
aesthetics while improving biodiversity and water conservation, limiting
pesticide and fertilizer use, and reducing energy use. See the Lexington
Preferred Planting List,[1] or genotypes found in EPA Eco Region III for planting
trees and shrubs.
In order to minimize watering needs, turf grass seed mix must use
region-appropriate, drought-tolerant species (primarily fescues, some
clover). Avoid a monoculture grass with only one species of grass
used. The use of lawn alternatives ("no mow") should be considered
for areas to be left unmowed.
Shrubs and herbaceous vegetation planted in nonturf areas must include
native species on the Lexington Preferred Planting List, or genotypes
found in EPA Eco Region III sufficient to achieve 70% aerial coverage
in 10 years. The sum of the DBHs of native trees on the Lexington
Preferred Planting List, or genotypes found in EPA Eco Region III
for newly planted trees must also comprise at least 70% of the total
DBHs of all newly planted trees.
If there are no street trees and room exists, trees shall be planted
along the frontage and spaced so that the trees can grow. Tree spacing
should be approximately 30 feet.
In transition areas, the Board may require vegetation and fences
or walls to provide an effective year-round visual screen six to eight
feet in height.
Incorporate trees that are native species or cultivars of native
species, drought-, shade- and salt-tolerant plants of varying heights
and species at parking islands and edges to diminish the heat-island
effect.
Rehabilitate lost or degraded stream channels, wetlands, and associated
native plant communities. Protect riparian and shoreline buffers where
required by law or where otherwise feasible, exceed requirements.
Conserve water resources and minimize energy use by reducing or eliminating
the use of potable water for landscape irrigation after the establishment
period. Rainwater irrigation systems are encouraged, such as the use
of cisterns. In order to reduce evaporation, the use of nonsprinkler
irrigation is preferred. Hand watering during the establishment of
new plantings is preferred.
Maintain healthy soil ecosystems by preventing soil compaction, chemical
contamination, avoiding excessively steep slopes, and preventing the
loss of organic matter and biological activity in the soil.
Support healthy plants, biological communities, and water storage
and infiltration by restoring damaged soils, protecting healthy soils,
and limiting soil disturbance during construction.
Multifamily developments shall provide private outdoor social, recreational,
or leisure space for residents in a development. Such space may be
a balcony, deck, or porch for individual dwelling units.
Residential amenity spaces are shared between residents of a building
or residential development. Residential amenity space may include
the following: a courtyard, rooftop, pool area, play area, playground,
terrace or similar gathering space. The residential amenity space
and required play area (where applicable) shall be at least 24 square
feet per dwelling unit for projects with greater than 20 dwelling
units. The residential amenity space shall be contiguous.
In addition to the residential amenity space, mixed-use developments
shall include a shared amenity space available to nonresidential users.
Shared amenity space may include features such as pedestrian walks,
benches, landscaped areas, plazas, additional sidewalk circulation,
or seating areas. In the case of a mixed-use development the total
amenity space shall be at least 5% of the developable site area.
Streetscapes in front of buildings should enhance the public realm
by contributing to the area's walkability and providing opportunities
for pedestrian engagement with streetscape furniture and plantings.
In natural areas or areas of recreation, create interpretive signage
and selective use of individual plant labels to identify the genus
and species of plants.
Provide wayfinding signage that directs users and visitors to pedestrian
and transportation nodes, landscapes, buildings, historical and cultural
locations, and other destinations.
Downward-directed, dark-sky compliant, energy-efficient lighting
is required to provide a minimum lighting level for evening activities,
particularly near site and building entries, pedestrianways, and within
parking lots.
Outdoor lighting should be no brighter than necessary. Lighting shall
use 3,000K or warmer fixtures and < 2,700
Kelvin is preferred as it is more wildlife friendly.
Minimize unnecessary nighttime lighting by using motion-activated
controls or timers that dim or turn off exterior lights beyond regular
hours of operation. Other than what is necessary for security purposes,
exterior lighting shall be shut off one hour after the last employee
leaves.
Use top-mounted sign lighting with shields so that the light falls
entirely on the sign and is positioned so that the light source (bulb)
is not visible from any point of the property or the roadway.
Wastewater. There shall be adequate capacity to meet the flow demands
of the proposed use under the standards of the Department of Public
Works, the Board of Health, and the Massachusetts Department of Environmental
Protection.
Utility meters and other infrastructure elements shall be located
in low visibility areas, screened from view, and designed to blend
in with the design. The Board may require plantings, fencing, or other
similar visual mitigation to assure an attractive visual environment.
Pocket parks, plazas, terraces, and other civic gathering spaces shall incorporate low-impact development techniques consistent with Appendix VI-B of Chapter 181 that address stormwater on-site quantity and quality.
Reduce impervious surfaces and consider opportunities for permeable
pavement where applicable. Drain impervious surfaces into on-site
landscape areas. (Examples include rain gardens and vegetated retention
ponds.) Reduce stormwater collection and removal from site. Avoid
creating chutes off impervious surfaces that will cause erosion in
the landscape areas.