“Sunblock” covers pavement to reduce heat (Courtesy of city of Austin)

Mitigating the effects of extreme heats in cities, worsening each year due to human-caused climate change, will require an array of creative responses.

Austin recently undertook one such effort by treating a stretch of road in Southeast Austin with “cool pavement technology” designed to reduce the “heat island effect” common in urbanized areas.

Throughout the United States roads have traditionally been paved with black asphalt, but dark colored surfaces absorb more heat and with summer temperatures hitting 100 degrees more and more frequently, roadways paved in black asphalt will be more prone to overheating and cracking. Enter ARA1-Ti Plus treatment, a pavement seal made of a water-based emulsion with titanium dioxide, better known as “road sunblock.” It can be sprayed onto a black roadway in a lighter color, which allows it to absorb less heat.

The city’s Engineer Pavement Maintenance Management (EPMM) team did just that in November 2022, spending $17,000 to treat a less-than-a-mile segment of Meinardus Drive with the cool pavement spray. Researchers at the University of Texas have collaborated with the city to study effects of the treatment; recently, they found that, in some cases, the cooling spray reduced asphalt temperatures by 10 degrees.

The city’s Transportation and Public Works department does not have any funding set aside for treating more roadways with sunblock in the fiscal year 2023-24 budget (set for adoption this week). But the Engineer Pavement Maintenance Management has applied for a $1 million federal grant, to be awarded next month, that could allow the city to treat about 25 miles of South Austin roadway with the spray. The city does not currently have a prioritization list for which roads should get lathered up first, but a spokesperson says they’re aiming for residential areas with pavement in good condition.