Editing Hybrid vehicle (section)

===Hybrid fuel (dual mode)===
[[File:Ford Escape E85 Flex Plug-in Hybrid views and badging WAS 2010.jpg|thumb|right|[[Ford Escape Plug-in Hybrid]] with a [[flexible fuel]] capability to run on [[E85]] ([[ethanol]]) ]]
In addition to vehicles that use two or more different devices for [[Ground propulsion|propulsion]], some also consider vehicles that use distinct energy sources or input types ("[[fuel]]s") using the same engine to be hybrids, although to avoid confusion with hybrids as described above and to use correctly the terms, these are perhaps more correctly described as [[dual mode]] vehicles:
* Some [[trolleybus]]es can switch between an onboard [[diesel engine]] and [[Overhead line|overhead electrical power]] depending on conditions (see [[dual-mode bus]]). In principle, this could be combined with a battery subsystem to create a true [[plug-in hybrid]] trolleybus, although {{As of|2006|lc=on}}, no such design seems to have been announced.
* [[Flexible-fuel vehicle]]s can use a mixture of input fuels mixed in one tank—typically [[gasoline]] and [[ethanol]], [[methanol]], or [[biobutanol]].
* [[Bi-fuel vehicle]]: [[Liquified petroleum gas]] and [[natural gas]] are very different from petroleum or diesel and cannot be used in the same tanks, so it would be challenging to build an (LPG or NG) flexible fuel system. Instead vehicles are built with two, parallel, fuel systems feeding one engine. For example, some Chevrolet [http://www.chevrolet.com/culture/article/bi-fuel-silverado-natural-gas.html Silverado 2500 HDs] can effortlessly switch between petroleum and natural gas, offering a range of over 1000&nbsp;km (650&nbsp;miles).<ref>{{cite web|title=Bi-Fuel Silverado 2500HD Can Switch Between Gasoline And Natural Gas|url= http://www.chevrolet.com/culture/article/bi-fuel-silverado-natural-gas.html|access-date=2013-03-31}}</ref> While the duplicated tanks cost space in some applications, the increased range, decreased cost of fuel, and flexibility where [[Liquefied petroleum gas|LPG]] or [[CNG]] infrastructure is incomplete may be a significant incentive to purchase. While the US Natural gas infrastructure is partially incomplete, it is increasing and in 2013 had 2600 [[CNG]] stations in place.<ref>{{cite web|title=Alternative Fueling Station Counts by State|url=http://www.afdc.energy.gov/fuels/stations_counts.html|access-date=2013-03-31}}</ref> Rising gas prices may push consumers to purchase these vehicles. In 2013 when gas prices traded around US{{convert|4.0|$/usgal|$/l|order=flip}}, the price of gasoline was US{{convert|28.00|$/MMBtu|$/MWh|lk=on|order=flip|abbr=off}}, compared to natural gas's {{convert|4.00|$/MMBtu|$/MWh|order=flip|abbr=in}}.<ref>{{cite web|last=Halber |first=Deborah |title=What is the energy of gasoline compared to the same cost of other fuels in BTUs per dollar? |url=http://engineering.mit.edu/live/news/39-what-is-the-energy-of-gasoline-compared-to-the |access-date=2013-03-31 |url-status=dead |archive-url= https://web.archive.org/web/20130406211227/http://engineering.mit.edu/live/news/39-what-is-the-energy-of-gasoline-compared-to-the |archive-date=2013-04-06 }}</ref> On a per unit of energy comparative basis, this makes natural gas much cheaper than gasoline.
* Some vehicles have been modified to use another fuel source if it is available, such as cars modified to run on [[Autogas|autogas (LPG)]] and diesels modified to run on [[waste vegetable oil]] that has not been processed into biodiesel.
* Power-assist mechanisms for [[bicycle]]s and other [[human-powered transport|human-powered vehicles]] are also included (see [[Motorized bicycle]]).