How painting the streets could cool district heating – NBC 5 Dallas-Fort Worth
Some US cities are experimenting with reflective pavement coatings to cool hot streets while the two largest cities in North Texas have rejected such street coatings.
In this heat wave, the pavement cooks to an even higher temperature than the air. Hot pavement, spread across an entire city, helps create what is known as an urban heat island effect.
Darker asphalt is even hotter than hot concrete because the darker color absorbs heat.
Dallas Civil Engineer Tom Witherspoon knows pavement, but you don’t have to be an expert to know what his feet can tell him in this brutal heat.
“I know concrete. If I walk barefoot on it, I’ll burn my feet. But, with asphalt, it’s even hotter and that’s an even bigger problem,” Witherspoon said.
Four years ago, NBC 5 reported on a City of Los Angeles experiment with reflective pavement on some streets. Los Angeles has concluded that reducing heat from hot streets is a public health issue because heat-related illnesses are a year-round problem there.
“The pavement hasn’t changed in 50 years, so it’s good for all of us to open our minds to new possibilities,” said Greg Spotts of the Los Angeles Department of Public Works.
On a sunny day, he demonstrated how a section of asphalt pavement was 130 degrees while an adjacent paved section was 118 degrees.
Los Angeles is now extending the paved street experience to every street in an entire neighborhood. The city of Phoenix, Arizona also uses reflective surfacing on some streets to reduce heat.
“I have questions. Like, how long is it going to last? Because you drive cars on it. How well is it going to stick to asphalt?” Asked Witherspoon.
Sure enough, the City of Dallas has provided a statement indicating that other options are being considered instead.
“The public works department had already looked into the ‘cool’ pavement, but since maintenance was a big challenge, the concept was not pursued. However, we are currently evaluating alternative materials for street and alley pavements. More work needs to be done,” the statement from Dallas said.
The city of Fort Worth said the reflective coating was inconvenient for drivers.
“The City of Fort Worth has moved away from white or brightly colored surface materials due to reflectivity. After receiving several complaints from residents, it was determined that darker colored (non-glare) sidewalks were more “easy for drivers. We’re always looking for new types of pavements and surfacings that we think could benefit our residents, but we haven’t found one that reduces glare for drivers to our standards,” says the Fort Worth press release.