At the headquarters of the Hampton Roads Planning District Commission in Virginia, staff recognized the urgent need to repair their deteriorated asphalt parking lot. Rather than replacing it with conventional asphalt, they opted for a sustainable alternative. Completed last year, the new parking lot features porous concrete panels and areas with native plants and recycled materials. This design helps cool the lot and reduces flooding risks.
Communities and organizations across the United States are adopting alternatives to traditional asphalt to address heat and manage water runoff. As Jill Sunderland, the commission’s senior water resources planner, explained, the new panels allow rain to penetrate faster, preventing puddles on the surface. Sunderland noted, “You can tell a difference, not to mention it’s more inviting.”
The City of New Orleans mandates the use of permeable paving for practical areas in public works. In Indianapolis, the Newfields art museum replaced traditional blacktop with bioretention rain gardens and a permeable grid. Denver’s dePaving a Greener Denver aims to decrease the city’s impervious surfaces. Other cities have eliminated minimum parking space requirements for new buildings, including Buffalo, New York; Austin, Texas; and Minneapolis.
Innovative Cooling and Shading Techniques
People walk through a parking lot with solar panels near Lincoln Financial Field, Philadelphia. (AP Photo/Matt Slocum, File)
Parking lots take up substantial land in many downtown areas, and studies indicate that many spaces are unused. To address these issues, grants are available for entities to transform hardscape areas, traditionally made from asphalt.
Innovations like reflective surface coatings reduce heat absorption, as implemented in Los Angeles’ Pacoima neighborhood. Vegetation further helps regulate temperature by absorbing energy and releasing moisture. Sacramento requires enough trees planted to shade half of new lots within 15 years. Washington, D.C., and Seattle impose green area requirements in landscaping. Solar panels also double as shade structures.
Without these adaptations, dark pavements can increase temperatures by up to 20 degrees, contributing to the urban heat island effect. This leads to increased reliance on air conditioning, pushing hot air outside.
Managing Stormwater Runoff
Alternatives like porus materials help rainwater absorb into the ground, mitigating runoff. Left uncontrolled, runoff can carry pollutants into nearby waterways. Innovative solutions include lattice pavers that support grass growth and interlocking pavers that allow water to filter through. Bioswales and rain gardens use sand, soil, and plants to filter pollutants before reaching streams or sewers.
The Hampton Roads Planning District Commission employs a stamped, grooved concrete border to trap sediment between traditional and porous concrete. At Indianapolis’ Newfields museum, rain gardens are paired with recycled plastic grid pavers in overflow parking areas.
Cost Considerations for Alternative Materials
Ronnie Jefferies paints a Georgia parking lot to make it more reflective. (AP Photo/Mike Stewart, File)
Alternative materials may require higher initial investment. Sunderland acknowledged that while repaving with asphalt would have been cheaper initially, the alternative offers more longevity. Buzz Powell, technical director at the Asphalt Pavement Alliance, emphasized asphalt’s versatility and ability to handle traffic. He advised careful consideration of alternative systems’ life cycle impacts.
Porous asphalt is gaining popularity. Powell argues that better mixing materials, structural pavement design, and pavement preservation can enhance asphalt’s benefits. He acknowledged financial constraints might affect cities’ efforts to retrofit existing lots, noting the vast acreage of asphalt that requires upgrading.
Ultimately, improving parking lot construction or reducing their size addresses challenges like heat, water quality, and inequality. Greg Kats, founder of the Smart Surfaces Coalition, stated that while a single city may have limited impact, realizing the benefits on a larger scale could drive change.
Leave a Reply