Glossary of Terms

2D/4D – 2 door/4 door

2WD/4WD – 2-wheel drive/4-wheel drive

Annual Fuel Costs – This is calculated by dividing your annual miles driven by the vehicle’s typical miles per gallon and multiplying that number by the cost of fuel

Annual Greenhouse Gas Emissions – This is based on tailpipe emissions and emissions from the production and distribution of the fuel type used. The emissions are calculated by multiplying your annual miles driven by the vehicle’s grams per mile of greenhouse gas emissions

Annual Smog Emissions – This is based on tailpipe emissions only. The emissions are calculated by multiplying annual miles driven by the vehicle’s grams per mile of NMOG and NOx.

AT PZEV (Advanced Technology Partial Zero Emission Vehicle) – A vehicle emissions rating within California’s exhaust emission standards. AT PZEV meets the same requirements as a PZEV (meets Super Ultra-Low Emission Vehicle exhaust emission standard, has zero evaporative emissions and includes a 15-year/150,000-mile warranty on the emissions system) and includes zero-emission vehicle enabling technologies

AWD – All-wheel drive

BEVBattery-electric vehicles run on electricity stored in batteries and have an electric motor rather than a gasoline engine

BIN – Names for federal emission standards

CARB – The California Air Resources Board is a regulatory agency under the California Environmental Protection Agency

Carbon Footprint – The total amount of greenhouse gases produced to support a household or other entity, including those caused by direct and indirect emissions

CalEPACalifornia Environmental Protection Agency

California Emission Standards – Standards adopted by California that regulate the emissions of vehicles sold in the state. California is the only state vested with the authority to develop its own emissions regulations, which are often more stringent than the federal rules. Other states have a choice to either implement the federal emissions standards or adopt California requirements

City Fuel Economy – Estimated miles per gallon during city or urban driving, in which a vehicle is started after not running for 12 hours and driven in stop-and-go traffic

CNGCompressed natural gas is a compressed mixture of hydrocarbons consisting mainly of methane

CO2 – Carbon dioxide is a colorless, odorless, poisonous gas that contributes to global warming

CO2 Equivalent Value – The sum of a vehicle’s greenhouse gas emissions used to determine its Greenhouse Gas Rating. Greenhouse gases (GHG) emitted from vehicles include carbon dioxide (CO2), methane (CH4), nitrous oxide (NO2) and hydrofluorocarbons (HFCs) (from air conditioner refrigerant)

Combined Fuel Economy – The fuel economy from driving a combination of 55% city and 45% highway miles, calculated as 1/[(0.55/city mpg) + (0.45/highway mpg)]

Direct vs. Indirect Emissions – Emissions from sources that burn fuels directly, such as a car or natural gas-fired water heater, are direct emissions. Indirect emissions are a consequence of actions at a home or another location that result in emissions elsewhere, such as at a power plant that produces the electricity used in your home

DOEDepartment of Energy

DOTDepartment of Transportation

Emission Certification Standard – EPA and California-required standards. The names for the standards refer to tables of numerical limits for the various air pollutants allowed by the standards

Engine Size – A vehicle’s engine size is measured by displacement, normally given in units of liters (3.2L = 3.2 liters) or number of cylinders. Larger, more powerful engines usually have more cylinders than smaller engines

Enhanced AT-PZEV – A vehicle that meets the AT-PZEV requirements and makes use of an off-board zero-emission vehicle fuel such as electricity or hydrogen. Please note that the new terminology for AT PZEV is Transitional Zero Emission Vehicle (TZEV)

EP LabelEnvironmental Performance Label

Ethanol (E85)Ethanol is an alcohol made primarily from corn and can be used in flexible fuel vehicles, or FFVs, which are capable of operating on gasoline, E85 (85% ethanol, 15% gasoline) or a mixture of both

Evaporative Emissions – Emissions that escape from the engine when a vehicle is idling

FCEVHydrogen fuel cell electric vehicles are zero emission and run on compressed hydrogen fed into a fuel cell "stack" that produces electricity to power the vehicle

FE – Fuel efficiency

FFVFlex Fuel Vehicle

Fuel Efficiency or Fuel Economy – Refers to the average number of miles traveled per gallon of fuel consumed

GHG – Greenhouse Gas

Global Warming – Greenhouse gases trap heat in the atmosphere, thereby creating a greenhouse effect known as global warming. Some greenhouse gases occur naturally and are emitted in the atmosphere through natural processes and some are created through human activities.

Global Warming Score or GW – A score that ranks each vehicle’s CO2-equivalent value on a scale of 1 (worst) to 10 (best) relative to all other vehicles. All vehicles manufactured after January 1, 2009, must display this score on the Environmental Performance Label

The greenhouse gas rating is based on emissions data from CARB’s motor vehicle greenhouse gas emissions regulation known as AB 1493 or Pavely. The greenhouse gas regulation establishes a CO2-equivalent value that includes all the various global warming gases based on their relative contribution to global warming. The CO2-equivalent value is as follows:

CO2 Equivalent = CO2 + 296xN2O + 23xCH4 – A/C Direct Emissions Allowance – A/C Indirect Emissions Allowance

Using this equation, and accounting for the upstream emissions factor for alternative fuels, CARB accounts for all global warming gasses being released into the atmosphere due to the operation of each vehicle.

Greenhouse Gases – Greenhouse gases emitted from vehicles include carbon dioxide (CO2), methane (CH4), nitrous oxide (NO2) and hydrofluorocarbons (HFCs) (from air conditioner refrigerant)

H2 – Hydrogen

HC – Hydrocarbon

HFCPHydrogen Fuel Cell Partnership

HFCs – Hydrofluorocarbons

Hybrid Electric Vehicle or HEVHybrids commercially available today combine an internal combustion engine with a battery and electric motor

Highway Fuel Economy – Estimated miles per gallon on the highway. Highway fuel economy represents a mixture of rural and interstate highway driving in a warmed-up vehicle, typical of longer trips in free-flowing traffic at higher-than-city speeds

Incentives – Tax credits, financial rebates/discounts or nonmonetary conveniences offered to encourage further use of advanced technology vehicles and alternative fuels. Search incentives

LEV 1 ULEV (Ultra-Low Emission Vehicle) – A vehicle emissions rating within California’s LEV 1 exhaust emission standards. The LEV 1 emission standards apply to cars from 1994-2003. However, some cars were still certified as LEV 1 after 2003

LEV 2 ULEV (Ultra-Low Emission Vehicle) – An emissions rating within California’s LEV 2 exhaust emission standards. The LEV 2 emission standards were adopted in 1998 and apply to cars from 2004-2010. However, some cars were certified as LEV 2 before 2004

LCFSLow Carbon Fuel Standard

LDT – Light-duty Truck

LEV I or Tier 1 Emission Standards – California emission standards that extend through the year 2003

LEV II Emission Standards – Emission standards adopted by California in 1998 which extend from 2004-2010

Li-ion – Lithium-ion battery

LNG – Liquefied natural gas

Make – The manufacturing company, or in some cases, a division of a manufacturing company, such as Chevrolet, Acura or Jeep

MPG – Miles per gallon, a measure of fuel economy

MPG(e) – Miles per gallon equivalent

Model – The name of the vehicle. In some cases, manufacturers subdivide a model according to various trim levels, such as Jeep’s Grand Cherokee or Toyota’s Camry Hybrid

Model Year – Model year refers to the actual annual production period (year) as determined by the manufacturer

MDV – Medium-duty vehicle

MSRP – Manufacturer suggested retail price

NOx – Oxides of nitrogen. NOx is a lung irritant. When combined with hydrocarbons and sunlight, NOx compounds form smog

Plug-in electric vehicle or PEV – These cars can be recharged from any external source of electricity and the electricity is stored in a rechargeable battery pack to drive or contribute to driving the wheels. These types of cars include battery-electric vehicles and plug-in hybrid-electric vehicles

PHEVPlug-in hybrid-electric cars are similar to traditional hybrids but are also equipped with a larger, more advanced battery that allows the vehicle to be plugged in and recharged in addition to refueling with gasoline. This larger battery allows the car to drive on battery alone, gasoline alone or a combination of electric and gasoline fuels

PM – Particulate matter. Tiny particles of solid matter that lodge in the lungs and form deposits on buildings. PM is a cancer-causing carcinogen

Partial Zero Emission Vehicle or PZEV – A vehicle emissions rating within California’s exhaust emission standards. Cars that are certified as PZEVs meets the Super Ultra-Low Emission Vehicle exhaust emission standard, has zero evaporative emissions from its fuel system and include a 15 year/150,000-mile warranty on the emissions system. PZEVs run on gasoline yet offer extremely clean emissions and an extended warranty and zero evaporative emissions

Regenerative Braking – Partial recovery of the energy normally dissipated into friction braking that is returned as electrical current to an onboard energy storage device

Smog – A haze-like form of air pollution produced by the photochemical reaction of sunlight with volatile organic compounds (including NMOG and NOx) that have been released into the atmosphere, especially by automobile emissions

Smog Score – Ranks a vehicle’s pollutant levels of non-methane organic gases (NMOG) and oxides of nitrogen (NOx) relative to all other cars within the current model year. Smog Ratings are on a scale of 1 (worst) to 10 (best). All new cars display this score on the Environmental Performance Label

Super Ultra-Low Emission Vehicle or SULEV – Have an emissions rating within California’s LEV 1 and LEV 2 exhaust emission standards

SUV – Sport utility vehicle

Transitional Low-Emission Vehicle or TLEV – Emissions rating within California’s LEV 1 exhaust emission standards

TIER1 – Emissions rating within California’s LEV 1 exhaust emission standards

Transmission – The gearbox that provides different gear ratios between the engine and the drive wheels, including reverse gear

Upstream Emissions – Emissions from processes prior to when the fuel is used in a vehicle, typically during extraction, production, distribution and dispensing. The upstream emissions of alternative fuels are taken into consideration when the Greenhouse Gas Rating is determined. 

U.S. EPA Fuel Economy Estimates – U.S. EPA estimates are based on vehicle-specific data from tests designed to replicate real-world conditions, which can significantly affect fuel economy: high-speed/rapid acceleration driving, use of air conditioning and cold temperature operation. Other conditions such as road grade, wind, tire pressure and fuel property differences are also considered. EPA Fuel Economy Estimates can be found

VMT – Vehicle miles traveled

ZEM – Zero-emission motorcycle

Zero-emission Vehicle or ZEV – A vehicle that produces no emissions from the onboard source of power. The only technologies that meet this definition are battery-electric vehicles and hydrogen fuel cell electric vehicles

Zero Emission VMT – The vehicle miles traveled with zero exhaust emissions of any criteria pollutant