By Elaina Sauber Charleston's newest mode of transportation is cheap, emission free and virtually silent. Autopods, a pedicab company started by two Carnegie Mellon graduates, is expanding outside of its Pittsburgh headquarters for the first time, to gauge its success in Charleston. At a news conference Friday at Haddad Riverfront Park, owners Tanuj Apte and Deepak Vidhani showed city officials firsthand what makes the three-wheeled Autopods unique. The pedal-powered microtaxis are battery assisted, to give drivers an extra boost when needed.