The pavement and asphalt industry has been around since the 1800s. In fact, Edmund J. DeSmedt, a Belgian chemist, laid the first true asphalt pavement in the United States in 1870 -- in Newark, N.J. With advances such as the automobile and air travel, pavement became, and continues to be, one of the largest U.S. industries [source: NAPA].
However, traditional asphalt and concrete pavements have a few disadvantages. As we've already mentioned, because these materials are nonporous (or impervious), rainwater cannot seep into them and instead runs off. As the water travels, it may also collect oil, gasoline and other pollutants as it washes into neighboring streams and rivers. This runoff can cause steady landscape erosion.
Additionally, traditional asphalt gets very hot, creating a "heat island" effect in urban environments. A heat island is exactly what it sounds like -- an area that is much warmer than its surroundings. (You can learn more about this phenomenon in What is the urban heat island effect?) Many manufacturers believe green pavement can change all that. We've already talked about green pavement's superior storm runoff management, but what else does it do for the environment?
- Companies can produce it with recycled materials. Traditional concrete requires a lot of energy to produce and that production creates a lot of waste. Most grass pavers consist of recycled plastic. Where green pavement does use concrete, new techniques allow manufacturers to reuse byproducts from other processes (such as collecting slag cement from iron manufacturing) to make concrete, which reduces landfill space [source: Green Highways Partnership].
- Permeable, light-colored pavement doesn't ice up as quickly in the winter because melting snow and rainwater don't pool on its surface. Even in freezing temperatures, permeable pavement tends to be warmer in the winter, due to the increased circulation of air within the pavement. This provides a safer walking and driving surface [source: Green Alley Handbook].
- Even though permeable pavement may be warmer in the winter, it's cooler than traditional pavement in the summer due to its lighter color and circulation. Lighter colored objects reflect heat rather than absorb it. The industry calls this light-colored pavement "high albedo pavement." It cools down the surrounding area and improves air quality by radiating less heat [source: Green Alley Handbook].
Now that we've addressed the green pavement pros, let's take a look at the cons.