News Earth Just how much do U.S. roads matter? By Susan Milius August 12, 2002 at 1:50 pm - More than 2 years ago Share this:Share Share via email (Opens in new window) Email Click to share on Facebook (Opens in new window) Facebook Click to share on Reddit (Opens in new window) Reddit Click to share on X (Opens in new window) X Click to print (Opens in new window) Print A road is a lot more than just a road, and Richard Forman of Harvard University has started to work out just how much more. Traffic noise, salt runoff, spread of exotic plants, and other impacts of U.S. roads affect about one-fifth of the nation’s land, Forman calculates.