possible advantages of serial hybrids in extremely traffic-dense environments. Based on a London test cycle, a reduction in CO2 emissions of 31% and fuel savings in the range of 40% have been demonstrated, compared with a "Euro-4" compliant bus. Former hybrid bus manufacturers ISE Corporation ThunderVolt (filed for bankruptcy in 2010) Azure Dynamics (filed for bankruptcy in 2012) Conversions Hybrid Electric Vehicle Technologies (HEVT) makes conversions of new and used vehicles (aftermarket and retrofit conversions), from combustion buses and conventional hybrid electric buses into plug-in buses. List of transit authorities using hybrid electric buses Transit authorities that use hybrid electric buses: North America United States Federal funding generally comes from the federal Diesel Emissions Reduction Act. ABQ RIDE (Albuquerque, New Mexico) Ann Arbor Area Transportation Authority (AAATA) (Ann Arbor, Michigan) Autoridad Metropolitana de Autobuses (San Juan, Puerto Rico) Baltimore, Maryland Bee-Line Bus System (Westchester County, New York) Berks Area Reading Transportation Authority (Berks County, Pennsylvania) Bloomington Transit (Bloomington, Indiana) Broome County Transit (Broome County, New York) Broward County Transit (Broward County, Florida) Capital Area Transportation Authority (Lansing, Michigan) Capital District Transportation Authority (Albany, New York) Central New York Regional Transportation Authority (Syracuse, New York) Charlotte Area Transit System (Charlotte, North Carolina) Chatham Area Transit (Savannah, Georgia) Chicago Transit Authority Citibus (Lubbock, Texas). Central Ohio Transit Authority (Columbus, Ohio) Clarksville Transit System (CTS) (Clarksville, Tennessee) Community Transit (Snohomish County, Washington) C-Tran (Vancouver, Washington) Citilink (Fort Wayne, Indiana) Cache Valley Transit District (Logan, Utah) DART First State (Delaware) Durham Area Transit Authority (Durham, North Carolina) Eureka Transit Service (Eureka, California) GoRaleigh (formerly Capital Area Transit) (Raleigh, North Carolina) Greater Lafayette Public Transportation Corporation (Lafayette, IN and West Lafayette, IN) Greater Lynchburg Transit Company (Lynchburg, VA) Greenville Area Transit (Greenville, North Carolina) Hillsborough Area Regional Transit (Hillsborough County, Florida) Howard Transit, (Howard County, Maryland) IndyGo (Indianapolis, Indiana) Jacksonville Transportation Authority Kanawha Valley Regional Transportation Authority Kansas City Area Transportation Authority King County Metro Transit Authority (Seattle, Washington) Lane Transit District (Lane County, Oregon) Long Beach Transit (Long Beach, California) LACMTA (Los Angeles, California) LANTA (Lehigh Valley, Pennsylvania) Madison Metro Transit (Wisconsin) Manatee County Area Transit (Manatee County, Florida) Massachusetts Bay Transportation Authority (Boston, MA) MATA (Memphis, Tennessee) MATBUS - Metro Area Transit (Fargo, ND - Moorhead, MN) Metropolitan Transit Authority of Harris County, Texas (Houston, Texas) Minneapolis-Saint Paul Metro Transit MTA Maryland (Baltimore, Maryland) Nashville Metropolitan Transit Authority New York City Transit Authority