Unpaved Fravel Road in Namibia (IMAGE) U.S. National Science Foundation Caption The scientists drove across 4,700 kilometers of Namibian roads, mostly unpaved gravel. Credit Paul Bierman, UVM Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.