Concrete and asphalt, things Dallas is in no short supply of, are making the city hot.
Dallas Planning and Development is proposing a code amendment limiting how much pavement builders can use in new developments. It could go before the City Council by the end of this year.
PDD's proposed amendment would limit the amount of “impervious surface” that can cover newly built residential and nonresidential lots. Impervious surfaces are hard materials like concrete or asphalt that prevent rainwater from penetrating the ground. They also absorb 95% of the solar energy that hits them, raising the temperature around them.
The goal is to encourage developers to incorporate more green space and trees, which cools things down on the ground.
“Everyone knows it's much nicer to walk down a hot street under shade than under direct sunlight,” said Jacob Miller, senior project manager at the nonprofit Smart Surfaces Coalition, which partners with Dallas and other cities to implement changes to mitigate heat.
Under the code amendment, the average new residential home would be limited to 500 square feet of pavement, which would allow for a two-car driveway, an entryway area and a walking path to the door. The limit would be higher or lower depending on the size of the home and could be designed however a builder wants as long as it stays within the limit. PDD is holding virtual feedback sessions on the proposal Sept. 9, 11 and 16.
The amendment is part of a larger effort by the department and other city officials to combat so-called heat islands, when highly developed urban areas are hotter than surrounding areas because of the heat absorbed and trapped by concrete and other structures.
A new analysis by the Smart Surfaces Coalition found heavily urbanized areas in Dallas are 14 degrees hotter than other areas, and implementing certain building materials or more vegetation could reduce peak summer air temperatures by about 3 to 7 degrees.
In May, Dallas approved a major reform to its parking ordinance, eliminating most parking minimums. The new regulations could reduce the amount of future parking spaces built, which contribute to the heat island effect and cover 1,400 acres of Dallas, according to the analysis.
“By removing stringent parking requirements, the City is unlocking land for housing, green space, and smarter infrastructure,” Andreea Udrea, PDD's deputy director, said in a news release. “With Parking Reform and Smart Surface strategies, Dallas is continuing to take bold steps toward a more sustainable and livable city for everyone.”
Impervious surfaces, like roofs and pavement, can also be improved by using brighter materials and coatings that reflect solar energy and reduce the temperature, according to the analysis — much like Los Angeles did when it painted some of its roads white. Dallas has already required buildings to have "cool roofs" since 2013. Builders must use reflective material, vegetation or both on their roofs. The city also plans to allocate $500,000 to solar panel maintenance in next year's proposed budget.
The analysis also found reflecting sunlight can save the city and residents money because less heat means less money spent on air conditioning and less heat damage to materials.
“Smart surfaces can also deliver really substantial benefits across a variety of different categories,” Miller said. “Everything from (...) material lifespans to health from improving air quality and reducing heat related mortality and morbidity, energy savings from building energy consumption. And from our analysis, we saw these benefits totaling in the hundreds of millions, even billions of dollars, over a 35-year time frame.”
Ultimately, cooling the city down is less about comfort and more about public health: Heat stress is the leading cause of weather-related deaths, according to the World Health Organization. Even though this summer has been relatively mild, multiple cases of children dying in hot cars surpassed last year’s numbers, pushing the Texas Health and Human Services to issue a warning to parents. Furthermore, the city found in its own 2024 heat island study the hottest neighborhoods were in historically disadvantaged areas.
The city’s Climate Action Plan states it expects the city to get hotter if more is not done to combat climate change. By 2050, 30-60 more days out of the year could be over 100 degrees, according to the plan.
The action plan’s current goal is to “reduce the urban heat island index by 20%, 50% and 75% by 2030, 2040, 2050, respectively.”
Dylan Duke is KERA's Fall news intern. Got a tip? Email Dylan Duke at dduke@kera.org.
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