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PHILADELPHIA - MAY 13:  A young man test rides a battery powered Egovehicle bicycle during the Tour de Sol: Great American Green Transportation Festival May 13, 2003 in Philadelphia, Pennsylvania. The tour is a series of festivals linked by a road rally championship for advanced vehicles. Anyone can compete with a road worthy hybrid vehicle, alternative fueled, fuel cell, or solar assisted electric sedan, truck, bus, or motorcycle built by manufacturers, students, or visionaries. The event is being held during National Transportation Week, and Clean Air Month. (Photo by William Thomas Cain/Getty Images)