Philadelphia is piloting a new initiative to combat the intense summer heat in its neighborhoods by testing “cool pavement” in **Hunting Park**. This project, led by the city’s Office of Sustainability, aims to address the urban heat island effect, where certain areas can be significantly hotter—up to **20 degrees Fahrenheit**—than greener surroundings. The cool pavement, known as **CoolSeal**, is designed to reflect sunlight instead of absorbing it, potentially lowering surface temperatures.
The urban environment is largely composed of concrete and asphalt, which absorb heat during the day and release it at night. According to **Kamil Kaloush**, a professor of pavement engineering at **Arizona State University**, these materials cover extensive areas in cities and contribute to elevated temperatures. The goal of implementing cool pavement is to create a more comfortable living environment, particularly during heat waves exacerbated by climate change.
CoolSeal is being applied on two stretches of roadway near the **Hunting Park Recreation Center**. **Andrew Dodd**, program manager for heat resilience in the Office of Sustainability, stated, “We just want to make residents feel cool and comfortable in their neighborhoods.” The city views this pilot project as a step towards enhancing heat resilience across Philadelphia.
Monitoring the Effects of Cool Pavement
A team from the **University of Pennsylvania**, led by the **Composto Research Group** and the **Thermal Architecture Lab**, is closely monitoring these patches for their durability and temperature impact. This pilot is notable as it evaluates the coating’s performance in a humid climate, a first for such studies. **Russell Composto**, a professor of engineering at Penn, emphasized the need to assess how well the pavement withstands the freeze-thaw cycles typical of Mid-Atlantic winters.
The initial section of pavement was applied last summer using a single coat of CoolSeal. However, members of Composto’s team reported that the coating showed signs of wear, cracking in places. In response, a double coat was applied to the second test patch this summer. The cost for the CoolSeal material is estimated at **$0.60 to $0.80** per square foot, with the city investing approximately **$44,000** in the pilot.
Evaluating Effectiveness and Future Steps
The research on cool pavement has produced mixed results in other cities. For example, **Phoenix, Arizona**, has coated over **140 miles** of its roads with CoolSeal, resulting in surface temperature reductions of up to **12 degrees Fahrenheit**. However, the air temperature saw minimal change—less than **1 degree Fahrenheit** cooler over the cool pavement compared to traditional asphalt.
In Philadelphia, preliminary findings indicate that while the CoolSeal coating effectively reduces the temperature of the road surface, the impact on air temperature and pedestrian comfort remains uncertain. **Dorit Aviv**, director of the Thermal Architecture Lab, noted, “We didn’t see a consistently negative impact, but we don’t see evidence of clear improvement for human comfort.” Aviv suggested that strategies such as tree shading might be more effective for cooling urban areas.
Looking ahead, the team plans to continue monitoring the CoolSeal coating throughout the winter. City officials will evaluate the pilot’s outcomes in **fall 2026**. If the results are promising, the city may expand the use of CoolSeal. Should the pilot underperform, officials will consider alternative strategies, including cool roof coatings. Dodd stressed the importance of this pilot, stating, “Hopefully we get some really good results.”
