A Continued Evaluation of the Urban Heat Mitigation Potential of the San Antonio Cool Pavement Pilot

Cities are at the forefront of climate change in terms of both contributing to the changes and being vulnerable to its impacts, such as more extreme temperatures. One approach to increasing heat resiliency within urban environments is cool pavement, which is a water-based asphalt treatment that can potentially reduce temperatures by reflecting more sunlight, absorbing less heat, and emitting less longwave radiation. Cool pavement may help keep the surrounding air cooler and combat the urban heat island effect. In 2024, the City of San Antonio began a second phase of a cool pavement pilot in an effort to reach the goals of the city’s Climate Action and Adaptation Plan. Since the dominant findings among other cool pavement programs have been varied, we evaluated the thermal performance of the San Antonio cool pavement installations for 16 days during the summer of 2024. The data collected included surface temperature, air temperature, relative humidity, wind speed, wet bulb globe temperature and albedo. The field work evaluated the cool pavement sites as well as representative control sites to estimate how different types of cool pavement products influenced the street thermal characteristics relative to a traditional road surface. Initial findings indicated that the performance varied notably between the different cool pavement applications and that changes had occurred over time from the first field data collection efforts conducted during the summer of 2023. Overall, the project provides an example of how city-university collaborations can produce scientific data that is operationalized to help inform policy efforts to decrease urban heat extremes.