Chicago Offers Model For Sustainable Urban Design

Can the asphalt jungle be reengineered to help communities reduce pollution and conserve water?

The greening of a "street" may not sound like much, but a 1.5-mile stretch of road in Chicago’s Pilsen neighborhood is being lauded as the greenest street in America – as an example of how cities can use sustainable design principles to improve the urban ecosystem. 

The street is the first to use an innovative new roadway material called photocatalytic cement. UV light is absorbed by the material – it keeps the surface clean and it removes nitrogen oxide from the surrounding air.

The streetscape also includes Chicago’s first permanent wind/solar powered pedestrian lights and LED light poles – just two of the features that helped reduce energy consumption associated with the redesign by 42%.

Just as significant – the materials and design are important for an under-appreciated but very important purpose – stormwater management – the source of much of the pollution from city streets entering streams, bays and other nearby water. As much as 80% of average annual rainfall from the sewer system is diverted from waterways through a combination of bioswales, rain gardens and permeable pavements.

Chicago’s Department of Transportation has eight targets for the $14 million streetscape project, such as stormwater management, material reuse, energy reduction, and placemaking – giving it a community feeling.

25% of Chicago’s land area consists of streets and alleyways, so the city is prioritizing how they can be designed or retrofitted to save energy, harvest water and perhaps be carbon-neutral.

"This project demonstrates a full range of sustainable design techniques that improve the urban ecosystem, promote economic development, increase the safety and usability of streets for all users, and build healthy communities," says Gabe Klein, commissioner of the Department of Transportation. "It provides both mitigation and adaptation strategies by reducing its carbon footprint and integrating technologies that allow the infrastructure to address and adapt to climate change."

The project serves as a test case for Chicago’s Sustainable Urban Infrastructure Guidelines, which are expected to be formalized next year. They will guide planners in managing stormwater, reducing the heat island effect, adapting infrastructure to changing climate conditions, improving neighborhood quality of life, increasing economic development, and minimizing the use of scarce resources. 

"We are committed to improving how we address water, air quality, sustainable materials and energy consumption in our city’s infrastructure while creating places people enjoy living and working," says Karen Weigert, Chicago Chief Sustainability Officer. "Projects like these show that the transportation right-of-way is an essential component for improving environmental conditions, as well as mobility and accessibility in Chicago."

Here are other noteworthy features:

Material Recycling and Innovation

• Sidewalk concrete includes 30% recycled content (reclaimed asphalt, slag, ground tire rubber and reclaimed asphalt shingles).
• Over 60% of construction waste was recycled, and more than 23% of new materials were sourced from recycled content.

Water Efficiency

• The street is lined with 95 species of native plants, including grasses, shrubs, and trees, all irrigated by storm runoff 

Energy Reduction

• Solar-powered lights allow the skies to be dark at night, cutting light pollution
• 76% of materials used are manufactured and extracted within 500 miles 
• Microthin concrete overlay extends pavement life and increases solar reflectance. 

Urban Heat Island Effect Reduction / Air Quality

• Sidewalks and asphalt reflect summer heat and light
• Landscape and tree canopy cover are 130% higher than conventional designs 

Alternative Transportation

• Improved pedestrian safety through traffic islands and curb-corner extensions
• There are new bike lanes andimproved bus stop areas with signage, shelters and lighting

Monitoring and Evaluation

• The Dept of Transportation and Metropolitan Water Reclamation District are calculating the project’s return on investment. The particular focus is documenting stormwater runoff and analyzing the impact of the photocatalytic system on air quality. 

The project was funded largely through Tax Increment Financing and $800,000 in grants from the Federal Highway Administration, Illinois Environmental Protection Agency and Midwest Generation.

The community is educating visitors about the best practices used to create the streetscape through a walking tour and a guidebook that explains the project.

Here’s a video about how Chicago is reimagining its streets:

Chicago isn’t the only city that’s greening its infrastructure. Greenworks Philadelphia is that city’s plan for being the "greenest city" in the US by 2015. It includes a 719-page "Green City, Clean Waters" plan that manages the first inch of rainwater in a storm event via green infrastructure – it too is  considered the model for the country. 

Greening the world’s cities is a critical subject because urban areas will more than double in size by 2030, housing 4.9 billion people (up from 3.5 billion today), according to the UN study, Cities and Biodiversity Outlook.

Green design, such as green roofs, parks and trees, will filter dust, reduce pollution, absorb carbon, and keep cities cooler, while protecting plants and animals, and contributing to human well-being.

Most urban growth is expected in small and medium-sized cities, not megacities, where there are still important habitats. Even small gardens make a difference for native polliniators like bees, which have been experiencing sharp declines.