When the Hampton Roads Planning District Commission realized the asphalt parking lot outside its Virginia headquarters was crumbling, staff did not reach for another load of blacktop. Instead, the regional agency installed porous concrete panels and patches of native grasses and shrubs. The lot, completed last year, now stays cooler under the summer sun and lets rainwater seep into the ground rather than sluice toward storm drains.
The choice is one example of a widening shift across American cities that are rethinking the country’s estimated 800 million parking spaces — the vast majority of them dark asphalt — as the atmosphere grows hotter and downpours heavier. Asphalt surfaces routinely reach temperatures above 150 degrees Fahrenheit on sunny afternoons and channel runoff into drainage systems that can overflow during intense storms, said Adam Millard-Ball, a professor of urban planning at the University of California, Los Angeles.
“Asphalt is basically a heat battery and a flood accelerator,” Millard-Ball said. “When you pave over a field, you lose the cooling effect of evaporation and you lose the sponge that used to soak up the rain.”
The U.S. heat-island problem is especially acute in lower-income neighborhoods, where tree cover is often sparse and parking lots are proportionally larger. Extreme heat already kills more people in the United States each year than hurricanes, tornadoes, and flooding combined, federal health and weather agencies have reported.
Indianapolis is among the cities responding. The city is preparing a pilot program that will convert several commercial properties — including the Clegg auto-repair shop at the intersection of 13th Street and College Avenue — from conventional asphalt to permeable pavers, said Jill Sunderland, the city’s senior project manager for stormwater.
“When you stand on one of those lots in July, you can feel the heat radiating up through your shoes,” Sunderland said. “We’re trying to turn those parking spaces into something that actually works with the water rather than against it.”
The program is supported by the Smart Surfaces Coalition, an Atlanta-based nonprofit that advocates for reflective coatings, solar canopies, and green infrastructure. The coalition is working with Indianapolis and three other cities to compile data on how much cooler and drier the alternative surfaces are compared with blacktop. Coalition founder Greg Kats said the goal is to give municipal budget offices a per-square-foot cost-benefit framework that city councils can act on.
“There’s a perception that permeable paving or reflective coatings are boutique items, but when you price the avoided flood damage and the avoided heat deaths, the calculus flips,” Kats said.
Other cities have already begun. Los Angeles has coated streets with a reflective sealant and offers incentives for cool-pavement technology. New Orleans is rebuilding some parking lots with gravel-and-plant systems that double as water-retention basins. Jonathan Wright, a civil engineer who advised the Hampton Roads project, said the Virginia commission’s new lot has performed well through one summer and one hurricane season so far.
“The panel design held up fine, and the drainage handled a tropical downpour without ponding,” Wright said. “That’s the kind of data that makes the next city’s decision easier.”
The asphalt industry has pushed back on the premise that paved lots must be replaced. The National Asphalt Pavement Association, in a 2025 statement, argued that porous asphalt technology can provide permeability comparable to concrete alternatives while supporting the recycling of asphalt material. Millard-Ball said the industry’s claim has technical merit but that building-code standards in most cities do not yet require porous asphalt as a default, which limits its adoption.
“The product exists,” he said. “What’s missing is the political will to write it into the spec book.”
The push coincides with a series of MSI reports on climate-driven infrastructure strain — among them an examination of aging drainage systems after an Omaha sinkhole exposed how loess soils and failing pipes can swallow roads, and a finding by federal scientists that roughly 100 Superfund sites are exposed to heightened flood, storm, and fire risk. The asphalt-lot experiments represent the same through-line: cities confronting the gap between infrastructure built for a cooler, more stable climate and the one they actually have.
For Sunderland, the Indianapolis pilot is partly a practical exercise and partly a public demonstration. “People need to walk on it, park on it, see that it doesn’t turn into a swamp,” she said. “Once they see it works, the next conversation is why we would ever go back to blacktop.”