AUSTIN (KXAN) — The City of Austin and the University of Texas are studying the environmental effects of cool pavement technology on a stretch of road in south Austin. Early results from the pilot program show temperatures are almost two degrees cooler than areas without the cool pavement treatment.

The city is looking at ways to reduce the urban heat that impacts cities across the United States. Some cities, like Phoenix, use cool pavement technology to combat the amount of urban heat.

Treating the roads

To test the pilot program, the city treated a 0.8-mile stretch of road outside of a public works building in south Austin. The treatment is sprayed from a truck onto the surface of the road. The substance looks almost yellow when it is first applied, but the finishing product makes the roadway lighter in color.

Angela Johnson, the division manager at the office of the city engineer, said regular asphalt will absorb up to 95% of sunlight that radiates the heat back into the surrounding area. It adds to the amount of urban heat you feel.

The treated roads will reflect more sunlight and radiate less heat in the surrounding area. To test the treatment, the University of Texas put sensors about eight feet off the ground at the pilot sight located on Meinardus Drive, and another sensor at a control location near Waller Beach at Town Lake Metropolitan Park.

The preliminary results show the treated roadway is between 0.6 and 1.8 degrees Fahrenheit cooler. Although the difference may not seem like much, Johnson said the impacts could be bigger with a larger treatment.

“It’s a beginning, and the more area we pave with that treatment, and preserving our right-of-way, trees definitely should help. It’s better to have a little bit than nothing,” Johnson explained.

Johnson said studies have shown cool pavement technology to reduce the ambient air temperature by 10 to 15 degrees in some cases. The city is hoping to treat another 10 lane miles next fiscal year. It has applied for a federal grant to fund the program extension. Johnson said the treatment cost about $25,000 to treat one mile of road.

An asphalt rejuvenator

The cool pavement treatment not only reflects more sunlight, but also acts as an asphalt rejuvenator, Johnson explained.

“It penetrates deeply in asphalt and restores original properties, like flexibility. Because over time, the oxidation in the environment, with heat, asphalt is losing its original flexibility and becoming more brittle and cracking,” Johnson said.