In October, the U.S. Transportation and Energy Departments announced plans to increase fuel efficiency for future vehicles manufactured and sold in the Unites States.  Under current regulations, those vehicles would need to meet a fuel efficiency standard of 15 kilometers per liter by 2016.  Tighter restrictions would apply to cars and trucks manufactured beginning in 2017.  To meet the demand, manufacturers are turning to battery-powered technology and electric-gasoline hybrids to meet the new restrictions.  But as VOA’s Kane Farabaugh reports, an often overlooked and historically maligned technology is already available, that could provide a short-term solution to higher fuels standards.