Los Angeles painting city streets white in bid to combat climate change

Sometimes the answers are really simple.  Defecting heat on streets is a great compliment to the same practice, in place for years, on rooftops.

You wonder if there's additional visibility and safety improvements as an added bonus to the lighter color? 

Los Angeles painting city streets white in bid to combat climate change

By Travis Fedschun

Officials in Los Angeles are painting streets white to reduce the effect of urban "heat islands."  (LA Street Services)

California officials are hoping their latest attempt to stem the rising tides of climate change leads to a more socially conscious -- and cooler -- summer.

Officials in Los Angeles have been painting streets white to reduce the effect of urban "heat islands" and combat the effects of climate change.

The LA Street Services began rolling out the project last May, which preliminary testing shows has reduced the temperature of roadways by up to 10 degrees. The project involves applying a light gray coating of the product CoolSeal, made by the company GuardTop.

"CoolSeal is applied like conventional sealcoats to asphalt surfaces to protect and maintain the quality and longevity of the surface," according to the company website. "While most cool pavements on the market are polymer based, CoolSeal is a water-based, asphalt emulsion."

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While each coasting could can last up to seven years, they are also pricey, with the estimated cost of $40,000 per mile, the L.A. Daily News reported.

Each coating of CoolSeal is estimated to cost $40,000 a mile, city officials told the LA Daily News.  (LA Street Services)
 

CoolSeal does pass the California skid test in addition to the slip test for wet traction, and is applied in two coats, each 50 microns thick, over an asphalt roadway or a slurry-sealed asphalt roadway, according to the streets department.

By reducing the temperature of the city streets, officials say it can help reduce temperatures in the neighborhoods where the sealant is applied.

With its numerous streets and freeways, Los Angeles suffers from the "heat island" effect, which causes urban regions to become warmer than their rural surroundings, forming an "island" of higher temperatures.

The sealant has reduced roadway temperatures by up to 10 degrees in testing.  (LA Street Services)

"Heat islands occur on the surface and in the atmosphere," according to the Environmental Protection Agency. "On a hot, sunny summer day, the sun can heat dry, exposed urban surfaces, such as roofs and pavement, to temperatures 50–90°F hotter than the air1, while shaded or moist surfaces—often in more rural surroundings—remain close to air temperatures."

Los Angeles Mayor Eric Garcetti, who may make a run for president in 2020, has used the project as part of an overall plan to reduce greenhouse gas emissions in the city by 45 percent below 1990 levels by 2025.

"Climate change is a fact of life that people in Los Angeles and cities around the world live with every day. It is a grave threat to our health, our environment, and our economy — and it is not debatable or negotiable," he said in a statement last year after President Trump said he would walk away from the Paris Climate Agreement.