The technologies leading up to the modern California-standard vehicle have primarily been experiments involving different kinds of batteries. These include Lithium Ion (year), Nickel Metal Hydride (year), and Lead Acid (year). In addition to these, alternative forms of energy have been developed, such as biodiesel (a replacement fuel for diesel vehicles utilizing vegetable oils or animal fats, chemically reacted with an alcohol), hydrogen, compressed natural gas (CNG, a compressed hydrocarbon mixture mainly consisting of methane), and more. Different vehicle designs since 2004 include various versions of the Battery Electric Vehicle ([B]EV), i.e. Neighborhood EV (NEV), City EV (CEV), Full Function EV (FFEV), Plug-in EV (PEV), Hybrid EV (HEV), and Plug-in Hybrid [Electric] Vehicle (PHEV), as well as many forms of the Low Emission Vehicle (LEV), i.e. Transitioning LEV (TLEV), Ultra LEV (ULEV), and Super ULEV (SULEV), which meet California's LEV1 and LEV2 standards.
Ethanol is an alcohol made primarily from corn and can be used in a Flex Fuel Vehicle (FFV), which is capable of operating on gasoline, E85 (85% ethanol, 15% gasoline), or a mixture of both. Previous decades used what is called an Internal Combustion Engine (ICE), which inspired the Hydrogen ICE Vehicle (an ICE that runs specifically on Hydrogen fuel) and Hydrogen Fuel Cell Vehicle (HFCV or FCEV– the most recent design for California's vehicles, incorporating automated driving features). Besides the Nissan Leaf, Tesla has specialized in the Zero Emission Vehicle (ZEV). These are not limited to cars, as zero emission motorcycles (ZEM) and zero emission buses (ZEB or ZBUS) can also be found in California. Other advances include the Partial ZEV (PZEV), Advanced Technology PZEV (AT PZEV), and Enhanced AT-PZEV, which meets AT-PZEV requirements and also makes use of an off-board ZEV fuel such as hydrogen or electricity. Probably the most understandable of the modern technologies is regenerative braking– "the partial recovery of the energy normally dissipated into friction breaking that is returned as electrical current to an energy storage device" (Regenerative Braking).
California's LEV 1 exhaust emission standards were defined in 1994, measuring for Ultra Low- and Low-Emission Vehicles, and apply to cars made between 1994 and 2003 (with some later exceptions). The LEV 2 exhaust emission standards were defined in 1998, measuring for the same vehicles, but apply to cars made between 2004 and 2010 (with some earlier exceptions). California requires that a Global Warming Score (GW) be displayed on every car made since January 1, 2009. GW is a decimal (range of 1-10) score that ranks a vehicle's CO2-equivalent value; higher values are cleaner. This is not to be confused with Smog Score (SS), which ranks pollutant levels of Non-Methane Organic Gases and Nitrous Oxides, but measures with the same scale as GW. Since these technologies, a miles per gallon equivalent, "MPG(e)," has been applied to primarily electric vehicles. This measurement is based on Fuel Efficiency/Economy, which refers to the average distance traveled per unit of fuel consumed. California has also formed a measure to meet its own standards, called "California Miles Per Equivalent Gallon" (of fuel) or CMPEG.
These technologies can potentially lead to vehicles with automated driving features, self-sustained engines, and truly all unknown technology since the current majority fuels on Earth destroy the atmosphere and alter the environment, risking the end of most innovation.
