Hunting Park City Heat Mitigation: Evaluating Road Coatings for Thermal Comfort
Project Overview
This urban heat mitigation project aims to evaluate the actual impact of different roadway surface materials on human thermal comfort, with a specific focus on mean radiant temperature (MRT). As radiation can account for approximately 50% of total body heat exchange in still air, MRT is a dominant factor influencing how hot or cold people feel. It therefore serves as a critical metric for assessing material performance in outdoor thermal environments.
Study Site and Setup
The field study is conducted in Hunting Park, Philadelphia, along a road corridor divided into two sections: the north side uses conventional asphalt as the control group, while the south side is coated with CoolSeal, a reflective material designed to reduce surface heat. The data collection includes both fixed-point and mobile measurements to capture spatial and temporal variations under different shading, exposure, and environmental conditions.
Instruments and Methodology
A range of environmental monitoring instruments is used in the experiment. The Comfort Cube measures MRT by recording radiation levels from six directions. A pyranometer captures shortwave solar radiation, while air temperature and humidity sensors are positioned at three heights (0.1 meters, 0.75 meters, and 1.5 meters) to reflect thermal exposure at different human body levels. In addition, wind sensors record speed and direction, and GPS devices track spatial coordinates during mobile measurements. A thermal camera is also used to capture surface temperature across the entire photo scene, providing a spatially continuous view of ground-level heat conditions.
Key Findings (Preliminary)
Preliminary findings indicate that CoolSeal consistently exhibits lower surface temperatures compared to asphalt, both in shaded and sun-exposed areas. This performance is attributed to its higher solar reflectance and thermal emittance, which reduce heat absorption and enhance heat dissipation. However, MRT measurements and simulations suggest that the current dataset is insufficient to draw definitive conclusions, especially regarding variation across different times of day and seasons. Air temperature data likewise show no consistent differences between the two materials, indicating the need for further data collection across broader temporal and environmental conditions.
Future Research Directions
Future research will include field measurements during peak summer conditions along the same Hunting Park corridor. These will focus on spatial variations in temperature, radiation, and shading. Fixed-point observations, conducted at five-minute intervals per location, will collect shortwave radiation, longwave radiation, air temperature, and MRT for both CoolSeal and asphalt surfaces under varying sun exposure and seasonal conditions.
Simulation and Design Implications
The data collected will be used to calibrate and enhance MRT simulation models, making them more accurate in representing dynamic shading, directional radiation, material-specific thermal properties, and the effects of vegetation. An integrated MRT simulation framework will also be developed to assess the seasonal thermal performance and heat mitigation potential of different pavement materials throughout the day.
Broader Urban Design Impact
Ultimately, the results from simulations and fieldwork will support the development of urban design strategies that promote the use of reflective paving, shaded streets, and thermally comfortable public spaces. These insights will help inform heat-resilient urban planning and design practices that prioritize human comfort in increasingly extreme climates.