Sustainable Design

Sustainable Design Principles

Sustainable design is guided by three major principles: social, economic, and environmental sustainability. This means for a design to be considered sustainable, it must take into account all principles and plan to address all components. For example, a new park design can benefit a neighborhood by providing a place for people to meet and relax (social). The park can also be open to a farmers' market (economic), selling products from nearby farms. The park can be designed with local trees and bushes to create or restore local animal habitats (environmental). In this case, all principles are directly and indirectly addressed through the design.

Sustainable design strategies arise from a response to unregulated suburban growth or suburbanization outside of cities. Suburban designs are characterized by low density, with single-family housing as the main residential building option. Services, shops, and businesses are also planned separately, with little mixing of residential and commercial spaces. Combined with low street connectivity through cul-de-sacs and long residential roads, car dependency is requisite over walking and cycling. As a response to rapid urban growth, suburban growth is a cheaper, less-regulated method of building homes and businesses.

Despite cheaper land costs for residential and commercial development, high car dependency and expansive use of land are harmful to the environment and are contributing to climate change. High commuting times from suburbs to urban areas, or even from areas within suburban places, are linked to greater air pollution, as carbon dioxide (CO²) and other particulate matter are emitted from vehicles. With a lack of public transport, walking, or cycling options, uncontrolled suburbanization is not a sustainable design model.

Fig. 2 - Suburban development in Colorado Springs, CO; sprawl promotes car dependency and greater emissions

Sustainable Design and Construction

There are several sustainable design models that promote higher density, mixed-land use, greener urban spaces, and more access to public transportation. These components serve several purposes that meet sustainable design principles. By promoting these aspects, there's the potential for social cohesion as all people have access to and share a healthier environment. Higher density and mixed-land use allow for more economic opportunities, as businesses can be in closer proximity to customers. Finally, fewer emissions from decreased car dependency and more parks and green areas are environmental benefits. Let's explore some of these sustainable design models.

Mixed Land Use and Walkability

Land use refers to the way that governments or agencies have zoned different places for specific purposes (residential, commercial, industrial, etc.). Due to suburban growth policies, many towns and cities have designated these purposes far apart, with connections usually only possible via car. Historically, this was to protect residents in residential areas from harmful industrial pollutants by building them far from each other. However, this type of zoning now prevents mixed land use.

Mixed land use means removing single-zone areas for mixed residential, commercial, entertainment, and other services together on the same block, street, or neighborhood. This can be done by building residential apartments with retail and shop space on the first floor; building offices with residential or commercial space; or allowing commercial services to open in strictly residential areas.

Fig. 3 - Mixed land use in Bitola, Macedonia; mixed land use promotes walkability

Mixed land use has the benefit of bringing people closer to not only the goods and services they need, but also cultural, social, and institutional locations they want to access. With closer proximity to these things, walking can be the preferred and logical mobility option. Successful mixed land use designs also adopt a grid-like street design with narrow streets, with enough intersections for greater connectivity.

Transport-Oriented Development

Transport-oriented development is a planning design that connects mixed-use development with public transportation options. It maximizes both land use development and public transportation by specifically building dense, walkable areas around the bus, tram, or metro stop stations. Transit-oriented development promotes public transport use, reducing car dependency and encouraging sustainable growth.

Smart-Growth Policies

Policies drive sustainable design development and construction. Smart-growth policies are a range of policies to develop and grow cities while conserving the environment and resources. For instance, directing new building development close to existing transit options instead of outside cities. In other words, smart-growth is acknowledging urban growth while directing development to denser, walkable areas.

New Urbanism, an urban design movement promoting walkable and environmentally friendly neighborhoods, publishes several policy ideas for cities to implement smart-growth policies. These policies include having most needs met within a 10-minute walking distance by increasing density, mixed-use land, and transport-oriented development.

Sustainable Design Benefits

The benefits of sustainable design include lowering carbon emissions, building cities that are resilient to shocks in the environment, economy, or society, and creating new opportunities for cities to grow. Some cities that have transitioned to sustainable design models have experienced reductions in air pollution, an increase in land value (particularly around public transport stops), and an increase in opportunities for social engagement.

However, every city faces different challenges in implementing sustainable design. This can be due to a range of factors from political, economic, and social interests that oppose changes; the geographic location of a city; or a lack of funding and expertise to achieve it. Public engagement and participation are critical first steps in the process of designing a city. Sustainable design especially must take into account the interests of the residents in a city to successfully target and realize its goals.

Sustainable Design Examples

There are examples of sustainable design models around the world. Some cities have the benefit of having older infrastructure, with compact streets and a walkable environment. Other cities have only been built within the last 100 years and are growing more quickly than they can manage. Let's take a look at some examples.

Superblocks in Barcelona, Spain

Barcelona is an older city, first built over 2,000 years ago. It has experienced changes in population and rule from the Romans, the Visigoths, and the Moors over the centuries. Barcelona benefits from mixed-use development and high public transport use. However, Barcelona faces congested streets, poor air quality, and little space for growth.

Taking advantage of the long boulevards, block-like street design, and high density, the city of Barcelona implemented the superblocks project. Superblocks are a combination of connected streets around the city where pedestrians and cyclists are given priority over cars and other transit options. Essentially, the street is taken away from cars and given back to residents to build parks, add benches, and create safe places for children to play.

Although this is a simple street change, car emissions dropped and local air pollution improved. More people are outside and residents enjoy the changes in their neighborhoods.

Fig. 4 - A superblock street in Barcelona; no cars are allowed through with space only for pedestrians and cyclists

Metro Area Developments in Washington, D.C.

One of the most widely-used and successful rapid transit systems in the US was developed in Washington, DC. The success of the transit lines can be at least partially attributed to successful development around metro station stops. New development of offices, residential spaces, and commercial spaces have been major positive effects since the opening of the first rail line in the 1970s.