Incorporating Sustainability into Downtown Master Plans & Codes

Download Main Street Now PDF_2011_05/06

Let us ask the land where are the best sites. Let us
establish criteria for many different types of excellence
responding to a wide range of choice.” — Ian McHarg

More than 30 years ago, pioneering landscape architect and urban planner Ian McHarg wrote Design with Nature, a seminal work on how to break down a community into its appropriate uses and balance the needs of the local environment with modern development and growth.

His quote tells us where new growth should occur and that new development should be compatible with the local setting, climate, and environment. He also understood that effective criteria, as represented in plans and codes, were needed to properly balance growth and protect the environment that sustains us.

Although McHarg’s thoughts on protecting the environment were similar to other environmentalists before him, he was among the first of his generation to link good land-use planning with long-term community sustainability. His planning and design principles influenced a generation of planners, architects, and landscape architects who designed places, revitalized downtowns and traditional neighborhoods, protected environments, and created plans that promote livability and sustainability without further damaging the planet. In some ways, Design with Nature, written long before today’s smart growth and sustainability movements, is the first community sustainability guide.

In historic preservation circles, sustainability is everywhere. People are positioning preservation and the reuse of historic buildings as essential parts of the equation for reducing greenhouse gas emissions and slowing the prospects and impacts of climate change. They focus on sustainable design for historic buildings — how we can retrofit them with energy-efficiency in mind. Several years ago, there were few websites on greening and retrofitting historic buildings; today there are so many it’s hard to know where to start.

Certainly, because existing buildings account for almost 40 percent of carbon emissions in the United States, greening historic buildings in our Main Street districts should be an essential activity in reducing emissions and promoting sustainability. However, if we are to achieve true, long-lasting sustainability for our traditional commercial districts, we must also look at the bigger picture of how our communities grow and develop, beyond individual buildings.

Ian McHarg’s thoughts and beliefs on planning are just as relevant today as they were when he first wrote Design with Nature. If Main Street communities want to be truly sustainable, then we need to have the right “rules” and “criteria” — planning and development policies and regulations that promote downtown’s long-term viability, reduce sprawl and vehicular miles traveled (VMT), and protect the environment.

When it comes to sprawl, no matter how many people drive hybrid cars or install green roofs, our nation can’t possibly reverse climate change if we continue driving to the town’s edge to see a movie or shop for groceries. Nationally, the transportation sector is responsible for approximately 30 to 40 percent of carbon emissions and of these emissions, about 75 to 80 percent come from vehicular travel. Over the decades, vehicular miles traveled have increased dramatically as we’ve constructed more roads, which has made it easier for us to live further from where we work and shop. VMTs are projected to increase as communities continue to adopt development policies that encourage sprawl rather than concentrating investment in our traditional commercial districts.

A community’s comprehensive plan and zoning ordinance structures its land-use pattern, walkability, transportation, and the demand upon its environment and natural systems. If your plans and zoning codes do not support concentrated economic activity in the Main Street district, walkability between downtown and its adjacent neighborhoods, and the preservation of historic buildings, then it’s time to revise them.

“Greening” Your Plans and Codes

In many respects, downtown plans, development regulations, and zoning codes have always been concerned with sustainability. Plan elements and policies can protect the environment, encourage green space, discourage sprawl, protect historic resources, and promote the downtown’s economic viability. But even though a community’s planning policies may support sustainability goals, its zoning codes and other ordinances often create roadblocks or lack the necessary “teeth” to enforce the planning goals.

Obstacles come in many forms. For example, plans that don’t concentrate commercial development in the existing district can open the door for sprawling strip center development elsewhere in the community. Roadblocks to energy efficiency, as another example, can be found in zoning and building codes that restrict the use of solar panels and geothermal energy systems. Finally, design guidelines may need to be updated to include standards for energy-efficiency improvements to historic buildings. In these cases, auditing, revising, and updating current plans and codes may be sufficient to promote sustainability.

Another option is for Main Street communities to adopt more comprehensive, far-reaching sustainability plans and codes that address a variety of issues, such as energy-efficient and renewable energy sources, transportation, water quality, stormwater management, light pollution, wildlife, and indoor environmental quality. For now, let’s focus on existing planning tools and development policies, including community and downtown master plans and zoning codes.

Downtown Plans

A downtown master plan is one of the most important sustainability documents a Main Street community can have as it reaffirms the downtown’s role as the economic, cultural, and social center of the community. Downtown master plans have long been developed and adopted by Main Street programs and municipalities to guide decision making for public improvements, private investments, and changes to existing zoning codes and regulatory mechanisms.

These plans often have specific elements related to streetscape improvements, open space and parks, historic preservation, land-use and development opportunities, transportation and parking, and governmental and cultural facilities. Downtown master plans can also address sustainability concerns such as the reuse of historic buildings and existing infrastructure, the mixture of commercial and residential land uses to encourage pedestrian activity and less reliance on autos, and the guidance of development and reuse of vacant parcels and land inside, rather than outside, the downtown area.

In recent years, however, more and more communities are updating existing downtown plans, or creating new ones, to integrate sustainability policies and recommendations into their planning strategies. Here are some of the policies and plan elements that serve to “green” downtown master plans:

Location and available infrastructure. Downtown districts already possess the necessary infrastructure to accommodate current and future economic growth. Unlike greenfield development that requires new infrastructure, the downtown’s infrastructure, from sewer lines to streets, already exists and may only need upgrading. Reusing upper floors in downtown buildings and encouraging new infill development allows downtown workers and residents to walk to stores, restaurants, and other destinations, thereby reducing car trips and VMT. A downtown master plan must emphasize the sustainability benefits of its central location (known as locational efficiency) and existing infrastructure.

Walkability. No matter how beneficial the downtown’s location may be to potential investors and developers, if the district is not walkable, especially to surrounding neighborhoods, no substantial sustainability benefits will be realized. In the absence of walkability, VMT will increase as people continue to rely on their cars to get downtown or elsewhere. Here are a couple of ways to increase a commercial district’s walkability:

  • Reduce the number of parking lots;
  • Close any gaps along the street wall that discourage pedestrian activity; 
  • Require new buildings to have street-facing entrances in front, and make sure that street façades are lined with windows, awnings, signs, planters, and other signs of activity;
  • Employ traffic-calming techniques by making sidewalks wide enough so pedestrians feel safe, and reducing speed limits (which also decreases automobile carbon emissions); and
  • Adopt “complete street” concepts, like adding bicycle lanes, to make downtown streets accessible for all users.

Transit. Not all Main Street communities need mass transit facilities, but an increasing number are adding rail or bus services to their long-term sustainability efforts. Communities that already have transit facilities can use their downtown master plans to improve these systems as well as encourage future growth near the facility so that downtown workers and residents can access a regional transportation network. For example, Denton, Texas, a Great American Main Street Award® winner, recently adopted a downtown master plan with a transit-oriented development component to complement plans for a downtown rail station linked to the Dallas Area Rapid Transit System. Access to mass transit can help lower automobile carbon emissions and per capita VMT.

Density. Placing people and development on less land is the only true way to reduce sprawl and preserve the natural environment. Density is perhaps the key ingredient in making downtowns walkable and mass transit more viable. Despite the economic recession, communities are creating downtown plans that accommodate future development and “restorative” infill on vacant or underutilized land. Even in small and rural Main Street towns, additional density can be accommodated by reusing upper floors for housing, adapting vacant buildings for new uses, and developing parking lots (with supporting lower parking requirements).

Historic preservation. It is interesting that many downtown master plans still do not discuss historic preservation as a key sustainability component. Too often, the focus has been on ensuring that new development meets LEED or other green building standards. However, planners are beginning to recognize the sustainable and embodied energy aspects of rehabilitating and preserving historic buildings. They are incorporating preservation policy recommendations into downtown master plans, not just identifying where the most important historic buildings are located. Planning policies may include a new or strengthened preservation ordinance that restricts the demolition of historic resources or new design guidelines that recommend green and sustainable design improvements.

Sustainable streetscapes. More and more communities are exploring the installation of sustainable streetscapes and other public improvements that incorporate pervious pavers, more durable street paving materials, LED streetlights, rain gardens, and stormwater management systems that capture rain for watering downtown trees and flowers. Communities in colder climates are considering geothermal-powered, low-voltage radiant heating systems in downtown sidewalks to aid in melting snow and ice. Sustainable streetscape systems may be more expensive to design and install than ones without such features but the costs of maintaining streets, streetlights, downtown trees, and planter beds may be lower in the long term. A downtown master plan can identify the relative benefits and costs of sustainable design features as compared with streetscape improvement schemes that do not incorporate them.

Brownfields. Perhaps the clearest example of un-sustainable development is the brownfield, where industrial contamination prevents land from being developed into a new use. If a Main Street community is to encourage a diversity of uses and concentration of development, brownfield sites should be identified in the master plan, along with a set of actions to address the long-term remediation and reuse of these sites.

Pollution and waste management. Years ago, waste and pollution were issues rarely addressed in downtown master plans. Today, planning strategies need to explore how downtown businesses, institutions, and residents can collaborate to eliminate pollution and reduce waste. Downtown planning strategies may explore enhancing municipal or county responsibilities for pollution reduction and waste management, developing new programs or resources to assist downtown businesses in reducing waste, or establishing other public/private partnerships that facilitate specific waste reduction efforts. Main Street programs can take on specific roles in a waste reduction/pollution prevention strategy, including developing educational programs, launching recycling initiatives, or creating a “green business” program to recognize businesses that incorporate green and sustainability practices in their operations.

Energy Efficiency. Downtown businesses spend a lot of money on energy usage. That money flows out of the community to the regional utility, which does not support economic growth downtown. Downtown plans need to need to include energy-efficiency strategies that can help business owners reduce their energy usage, increase sales, and keep dollars in the local community to support additional business and job growth. Several energy-efficiency strategies that can be added to a master plan include rebates and incentive programs for building retrofits and new energy-generating equipment, or cooperative agreements with area utilities on a new downtown energy pricing scheme. A more far-reaching planning strategy might recommend development of a new district-wide energy system in which property and business owners access and share lower energy costs. West Union, Iowa, as an example, is planning a downtown geothermal system to lower energy costs for all property owners and businesses.

Economic resiliency and organic growth. Promoting economic diversity in traditional commercial districts is perhaps the most important sustainability principle that should be included in a master plan. Diverse economic uses, from retail and office to entertainment, ensure that downtowns can be more resilient in the face of market downturns and fluctuations. Allowing different uses also ensures that a downtown grows and develops organically over time, adapting to market conditions when they change. In this environment, historic buildings are reused to support new businesses and fledging economic growth. New buildings are only added when a downtown reaches its full occupancy and when additional growth necessitates it. An organic approach avoids the “big fix” projects or multi-parcel developments that require large areas of a commercial district to be demolished and cleared.

Design Guidelines

Design guidelines are familiar to us in the Main Street field — they are an important planning tool in educating building and business owners on a variety of design issues, including proper techniques for rehabilitating and restoring facades and storefronts. Essentially, design guidelines set the standards for design improvements to existing buildings and design plans for future buildings. In most Main Street communities, design guidelines are developed as a stand-alone document used primarily by the Main Street design committee and/or the historic preservation commission, especially if a local historic preservation ordinance requires mandatory design review.

Sometimes, design guidelines are created as part of a master planning process. If our master plans adopt new policies and strategies that encourage energy-efficient alterations to downtown buildings and businesses, then design guidelines will be a vital mechanism in educating downtown stakeholders on ways to make appropriate energy-efficient improvements. Current design guidelines will need to be revised or completely rewritten, depending on local needs, circumstances, and available resources.

Revising design guidelines is relatively straightforward and can be done in two ways. New information about energy-efficient improvements can be integrated into the sections on building material maintenance and façade and storefront rehabilitation. Alternatively, a separate energy efficiency chapter could be developed and inserted within the existing design guidelines This approach may be more feasible because a separate chapter may be easier to develop, write, and insert within an existing design guidelines publication. Additionally, users of the design guidelines may find it easier to find energy efficiency information when it’s put in a separate chapter.

When revising or creating design guidelines, Main Street programs may want to consider
the following energy efficiency and sustainable design topics:

Inherent sustainable design features. Design guidelines should list the sustainable design features already inherent in historic commercial buildings, such as operable awnings that can reduce heat gain into the building or the embodied energy in existing building materials. Property owners can lower their energy bills simply by maintaining their buildings’ historic elements.

Building envelope improvements. As a first step in planning energy-efficiency improvements, property owners should check to see if air is leaking out from where the roof, walls, windows, and doors meet. Offer specific guidelines on cost-effective improvements such as weather-stripping historic windows and installing insulation and new roofing materials.

Green roofs and energy-generating equipment. Stipulate that solar collectors, wind turbines, and green roofs be placed behind roof parapet walls or at the rear of the façade where they cannot be seen at street level. Recommend that property owners consult professional engineers to determine if the building and existing roof have the structural capacity to hold a green roof.

When incorporating sustainable design and energy-efficiency guidelines, be aware that green technologies are changing all the time and that the guidelines can quickly become outdated. The guidelines should be general enough so that users can understand available methods for energy-efficient improvements and their relative costs and benefits. The Illustrated Guidelines on Sustainability for Rehabilitating Historic Buildings, recently released by the National Park Service, provides useful information on greening historic buildings and can serve as a starting point and reference in updating design guidelines. Main Street design committees and historic preservation commissions should understand that guidelines for interior building improvements will be voluntary, while exterior improvements can be regulated if there is a mandatory design review process.

Zoning Ordinances

Zoning codes and ordinances are one of the primary means through which to implement a master plan, particularly planning policies and strategies related to energy efficiency, land use, transportation, stormwater management, and historic preservation. A master plan can specifically recommend ways of revising the zoning code to guide and regulate private-sector sustainability initiatives or remove obstacles or unintended barriers that prevent the implementation of downtown sustainability goals. Unintended barriers may include excessive parking regulations that discourage adaptive-use projects and upper-floor conversions, or the restriction of residential uses that could occupy vacant or abandoned historic industrial buildings.

Absent a master plan, a Main Street community may elect just to audit the zoning code to see if it encourages sustainability initiatives or hinders them. Ultimately it is up to the municipality and the Main Street program to determine how fast and how far to move toward a zoning code that incorporates sustainability measures. This section identifies key sustainability features that could be introduced into a downtown district zoning code.


  • Solar collectors. Revise the zoning ordinance to allow solar collectors and panels as an “as-of-right” modification to a building’s exterior. Zoning can prescribe where collectors can be installed on a building — at the building’s rear elevation or as part of an accessory structure like a garage. In some communities, height limits in zoning codes may prevent the installation of solar panels or collectors. Addressing solar access in the zoning code will assure owners that their solar collector investment is protected from future development that may block the sun from the collectors or panels. This means that building height limits may have to be adjusted in the zoning code.
  • Wind turbines. Include recommendations for wind turbines (if they can feasibly be installed on a historic building) in the zoning code.

Land Use

  • Mixed use. Allow a variety of uses to diversify downtown’s economic base and encourage the reuse of historic commercial buildings and their upper floors. In many Main Street communities, downtown zoning codes still prohibit upper-floor residential use or require too much parking for upper-floor residential conversions. Downtown parking requirements should be lowered or eliminated where feasible. Mixed uses are a critical factor in encouraging economic diversity.
  • Accessory dwelling units. Allow accessory dwelling units (ADUs) in adjacent residential neighborhoods as a way to increase density in areas surrounding the commercial district. Again, increased density serves to support the downtown economy and facilitate pedestrian movement between the downtown and the surrounding neighborhoods.


  • Walkability and access. Require new developments to provide sidewalks
    and other pedestrian and bicycle-related amenities.
  • Idling restrictions. Add zoning restrictions to reduce car idling in school zones, near train stations, and loading docks as a way to lower harmful carbon emissions.

Stormwater Management

  • Rainwater harvesting. Regulate the placement and installation of rain barrels to ensure that they aren’t placed on sidewalks where they might impede pedestrians. Although these items are often associated with residential neighborhoods, they could be allowed as accessory uses in downtown districts.
  • Parking requirements. Reduce parking requirements and allow shared parking facilities to encourage less impervious surfaces.
  • Permeable pavement. Encourage the use of pervious paver systems in parking lots and alleys to increase stormwater infiltration. Create standards for long-term maintenance to ensure that these systems continue to operate as intended.

Building Reuse

  • Parking and loading requirements. Revise the number of parking spaces, in both on- and off-street facilities, to satisfy parking requirements for building reuse and upper-story residential and office conversions.
  • Reuse variances. Eliminate the zoning variances that are required for building reuse wherever feasible. (A variance is an exception from the rules on the books.)

Waste Reduction and Light Pollution

  • Recycling and composting. Mandate areas within the district for on-site sorting of recyclables and small-scale, on-site composting programs to reduce the amount of organic materials and waste sent to landfills.
  • Light pollution. Encourage efficient light systems by regulating light spillover from buildings and private parking lot lighting.
    Consider “dark sky” ordinances to minimize light pollution and ensure the night-time sky is visible at ground level.

Other Planning Tools

Comprehensive sustainability plans and sustainable development codes have come to the forefront as new tools that can address sustainability throughout the entire community. Main Street programs often turn to the downtown master plan to address sustainability issues, but a comprehensive sustainability plan looks at the entire community, including other areas where development can affect the commercial district.

Community Sustainability and Sustainable Development Codes

Community sustainability plans and master plans are similar: both have an integrated set of policies and implementation steps. However, community sustainability plans integrate a range of sustainability issues and actions within more traditional comprehensive plan elements that focus on transportation, open space, economic development, land use, culture and arts, municipal facilities, and infrastructure.

Community sustainability planning policies can include encouraging more compact, interconnected residential and commercial development; new transportation modes such as bicycle lanes; the protection of environmentally sensitive areas; reduction of pollution and hazardous wastes; and the increased use of alternative, renewable energy systems in municipal facilities, new housing, and commercial developments. A community sustainability plan can be a separate stand-alone document or it can be incorporated into an existing comprehensive plan.

Sustainable development codes, much like a zoning ordinance, support the goals and strategies recommended in the community sustainability plan by mandating standards or offering incentives, such as requiring on-site bicycle storage facilities in lieu of parking spaces. Such codes may address a wide variety of sustainable issues from land use and transportation to energy efficiency and water quality. Like sustainability plans, sustainability codes can be created separately or as part of other codes and ordinances.

Why do community sustainability plans and development codes matter to Main Street programs? The process for creating such tools provides an opportunity for downtown stakeholders and Main Street leaders to advocate for downtown revitalization as a key action in achieving community sustainability. It can also help city officials, residents, and other stakeholders understand where development should take place and how new development in or near the community can affect downtown’s economic viability. Furthermore, sustainability plans can identify additional initiatives that can build on the Main Street program’s revitalization efforts by strengthening older neighborhoods, developing new land-use patterns that lower VMT, providing new transportation options, and reaffirming historic preservation as an important strategy in generating economic development and maintaining community character.

Like sustainability plans, historic preservation plans are effective tools in promoting preservation as a key sustainability activity for communities.

Preservation Plan

Interestingly enough, perhaps one of the most overlooked community planning and sustainability tools is the historic preservation plan, which has been used by hundreds of communities across the nation. Historic preservation plans have many purposes, including the identification of significant historic resources and districts and the establishment of policies and ordinances that protect against unwanted demolition. Historic preservation plans may also determine the need for new design guidelines and incentives to encourage building rehabilitation or revisions in existing planning policies and zoning codes to prevent them from impeding preservation and building reuse.

Such plans may also recommend a series of educational initiatives to inform citizens about their heritage and its value to the community. Main Street leaders and community preservation advocates alike may find preservation plans helpful when addressing downtown preservation issues and promoting historic preservation as a key element to downtown and community sustainability. A historic preservation plan can be created and adopted as a stand-alone document or as a separate chapter in a downtown master plan or community comprehensive plan.

Sustaining the Future

McHarg once said that the most important issue confronting mankind in the 21st century is the condition of the global environment. We must “green the earth, restore the earth, and heal the earth,” he said. Combining the effort of greening our historic buildings and developing planning and development policies and tools can help our communities achieve long-term sustainability and reduce the prospects of dramatic climate change. Certainly, coupling these initiatives with our ongoing work in revitalizing our traditional commercial districts should make us optimistic that we’ll reach our community sustainability goals and save the planet.