As heat waves gripped the United States this summer, Los Angeles took to the streets to help cool its residents.
The city painted roads with a gray coating called "cool pavement" and is planting more trees as part of its Cool LA project.
Conventional paving materials can reach 120-150 degrees in the summer. This heat is released back into the air, making cities like LA even hotter.
Because of its lighter color, cool pavement reflects sunlight and absorbs less heat. The city estimated that applying it to streets can reduce surface temperatures by as much as 15 degrees.
The effects of cool pavement are more apparent later in the afternoon. Because streets with cool pavement do not absorb as much heat during the day, they end up releasing less of it in the afternoon and evening.
Over the past four years, LA has gradually coated hundreds of miles of streets with cool pavement. The city is prioritizing neighborhoods that have a lot of concrete and asphalt with little shade.
As the city paints its streets lighter, it is also planting tree saplings — another strategy to reduce temperatures and make neighborhoods more livable.
While trees are effective at cooling neighborhoods by offering shade, it takes years for saplings to grow. Plus, they require a lot of water — Los Angeles is susceptible to drought, so relying too heavily on trees for relief could be too resource-intensive. That means cool pavement may have to do some of the heavy lifting. The good news is that it seems to be working.
"So many constituents are happy when we've applied cool paving in their neighborhoods," Ana Tabuena Ruddy, the city's chief sustainability officer, told KCRW-FM. "We are funded for over $4 million. And so we will definitely deliver that in the coming fiscal year."
LA resident Ryan Solomon told KCRW he thought cool pavement was a silly idea at first. Then the city applied it to one half of a street before completing the other half, and he said the difference could be felt.
"I was walking and it felt like a wave almost … like if you're on the Metro or something, and you step outside and you get that breeze of cold air."
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