The Unique Pavement Type That Is Helping Cool Down Neighborhoods Across The Country

As global temperatures rise, you might be wondering if there will ever be any relief. Searching for a way to beat the heat, some cities in the United States are experimenting with "cool pavement," which is paving materials that work to mitigate the causes of urban heat waves. These types of pavements can reflect, rather than absorb, the sun's rays and increase water evaporation to lower the outside air temperature. This could save you from a sweltering summer and reduce the heat in your home without blasting the AC.

While driving or walking down the street, you may have noticed a shimmering surface above the asphalt road. This is caused by the sun cooking the black surface, heating it like a skillet until the air above expands, becoming less dense. The density decrease changes how the air refracts light, creating a watery illusion above the road. Dark pavements like asphalt absorb up to 95% of the sun's rays, contributing to global warming and urban heat islands, which are the daytime warming air temperature in cities due to a lack of trees. By switching to lighter-colored pavements and reflective aggregates and coatings, cities like Philadelphia, Los Angeles, and Phoenix, are hoping to temper the rising heat index.

If you've ever sweated through a black shirt on a sunny day, you are well aware that dark surfaces absorb heat more than light ones. This phenomenon is measured in a unit called "albedo," which quantifies surface reflectivity. Light-colored pavements such as concrete naturally have a higher albedo than asphalt, but even asphalt can be made cool by applying reflective coatings.

Switching to cool pavements like concrete has other benefits too. Concrete is permeable, which allows stormwater to soak through and reduce runoff. The cooling effect keeps the remaining runoff from heating up waterways. This also improves driving visibility during and after rain events by decreasing the amount of water on the roadway. The light color of cooling pavement can improve nighttime road visibility as well, providing an overall safer and more comfortable driving experience. While the application of reflective coatings like CoolSeal in cities like Phoenix and Philadelphia helps to reduce the road temperature, there are mixed results when it comes to lowering the surrounding air temperature. These cities are still experimenting with ways to mitigate urban heat islands without replacing asphalt entirely, but even a small decrease in temperature applied broadly throughout an area would decrease environmental damage. You wouldn't just see the benefits in outside temperature. A more comfortable city could help cool your home without air conditioning.

If you do not live in one of the cities experimenting with cool pavement, it could be helpful to bring these technologies to your community's attention. You can suggest implementing cool pavements at your local town hall or HOA meetings, while also setting an example for the neighborhood by replacing your asphalt driveway with a light concrete one. For an added benefit, this will save you money on repair and maintenance in the long run since concrete is more durable.

In cities and neighborhoods, a combination of methods is most effective for lowering the heat. Cool pavement alone cannot solve the warming problem and should be paired with other cooling methods such as planting shade trees. Even inside your home, plants can make your house feel cooler in the summer, so adding more large foliage to your yard can make a serious dent in your summer electricity bill. Though the heat can never be truly banished, it can be brought back to more manageable levels.