If you are at all concerned about the environment or even just worried about the rising cost of gasoline, you’ve probably wondered about the realities and promises of electric, hybrid electric, ethanol, biodiesel, propane (LPG), natural gas (CNG), hydrogen, even compressed air, and other alternative vehicle power technologies. There’s another pair of alternatives you may or may not have considered - human-powered vehicles (HPV) and hybrid electric-assist human-powered vehicles. An HPV or perhaps an electric-assisted HPV-the other hybrid-may be in your future.