Summer-friendly sidewalks, streets are less hot

Valley residents may soon see fewer flooded streets during monsoons and less extreme temperatures in the summer thanks to a unique kind of pavement.

A group of researchers from Arizona State University showcased the material known as “pervious pavement” on Thursday and predicted it will soon be commonplace in the Valley’s city streets, sidewalks and parking lots.

“I think it’s going to start spreading like wildfire,” said Joby Carlson, a researcher at ASU’s Global Institute of Sustainability.

Pervious pavement lowers temperatures by not only reflecting more of the sun’s heat but also by allowing absorbed heat to escape faster and with greater ease than other kinds of pavement.

It also alleviates the strain on municipal sewer systems during rainstorms because more water will seep through rather than run off. That reduces pollution of waterways caused by runoff and allows surrounding vegetation to thrive in highly urbanized surroundings.

The team of researchers, which has support from various public agencies and private companies, dumped about 500 gallons of water onto a newly constructed pervious pavement parking lot at 10th Street and Mill Avenue in Tempe. Onlookers watched as it disappeared quickly into the ground.

Kamil Kaloush, an associate professor at ASU’s Ira A. Fulton School of Engineering, said he and his cohorts are still exploring many unanswered questions about pervious technology such as quantifying precisely how much heat it retains and how long it lasts.

Jay S. Golden, an assistant professor with the School of Sustainability, said while traditional asphalt reaches somewhere around 145 degrees in the heat of summer, pervious pavement reaches between 95 and 110 degrees.

Although it costs up to twice as much as traditional forms of pavement, prices will decrease as it becomes more popular with developers and municipalities, the researchers said. Kaloush also said pervious pavement requires less maintenance because it lasts up to six times longer than typical pavement.

“We need to look at the life-cycle costs and not the up-front costs,” he said. The surface material is already commonly used in Washington, California and Florida. So far, several Arizona municipalities including Glendale, Tempe and Phoenix are expressing interest.

Stew Waller, executive director of the Arizona Cement Association, said government and industry is recognizing the cost benefits of the so-called “green” construction trend, which uses environmentally friendly building materials such as pervious pavement.