Air Date: Week of July 23, 1999

This week, facts about... asphalt. The first asphalt road was constructed in 1870 on William Street in Newark, New Jersey. Today, almost two million miles of roads in the U.S. are paved with asphalt.

Transcript

CURWOOD: Going barefoot in the summer can be playful in the grass or splendid in the sand, but downright painful if that path is over sun-baked blacktop. Asphalt paving seems to be almost everywhere now, 129 years after the first asphalt road in the US was laid on William Street in Newark, New Jersey. But asphalt is far older than that. A road from King Nebuchadnezzar's palace to the north wall of the city of Babylon, built around 625 BC, was paved with, quote, "asphalt and burned brick," according to an ancient inscription. To date, nearly 2 million miles of road in the US is blacktop. The recipe is 95% stone, sand, or gravel, and 5% gooey petroleum that can be recycled if it cracks or weathers. Asphalt has its disadvantages, too. It makes cities hotter in the summer and keeps water from soaking into the soil. And if you're not content with simply driving on the stuff, you can always visit the Hot Mix Hall of Fame in Lanham, Maryland, which boasts 26 inductees. Their commemorative plaques are cast in bronze because, according to Hall of Fame officials, asphalt was not “structurally subtle enough.” And for this week, that's the Living on Earth Almanac.