Air Quality - The Automobile's Contribution To Air Pollution

fuel vehicles mtbe alternative

Automobiles dominate the transportation sector's share of energy-related carbon emissions. The transportation sector accounts for more than 65 percent of U.S. petroleum consumption and more than 75 percent of carbon monoxide (CO) emissions.

As shown in Figure 5.19, the United States leads the world in car ownership. In 2001 there were nearly 850 vehicles per 1000 people in the United States. This rate has more than doubled since 1960, when there were approximately 400 vehicles per 1000 people. The symbols along the U.S. trendline indicate vehicle ownership in 2001 in other countries. For example, in 2001 in western Europe ownership was just over 500 cars per 1000 people, a level experienced in the United States back in 1969. Vehicle ownership in 2001 was even lower in other parts of the world. With industrialization occurring in many developing countries, an increase in global automobile use and the emissions that accompany them is inevitable.

American states that do not meet CAA standards must do something to bring emissions into compliance with national standards. Because of California's extreme air pollution problems, the Clean Air Act Amendments (CAAA) allowed states to set stricter emission standards than those required by the amendments, which California did. These included strict new laws on automobile pollution. The remaining 49 states were given the option of choosing either the standards of California or the federal CAAA.

States have the freedom to cut their emissions in whatever manner they choose. Some states are phasing in tougher tests for auto emissions. In major metropolitan areas, particularly in the Northeast, owners of cars and light trucks are required to take their vehicles to centralized, high-technology inspection stations. The EPA estimates that approximately three-quarters of the vehicles pass the inspections on the first try. For those that do not pass, repairs must be made. Public protest over such inspections caused several states to temporarily rescind vehicle checks. These states must find other ways to cut their emissions. If they cannot bring their emissions down to comply with EPA standards, they may have to reinstate vehicle inspections. Politicians are finding such measures very unpopular with their constituents.

One of the major failings in reducing auto-induced smog is that efforts have focused on reducing tailpipe emissions instead of eliminating their formation in the first place. Automakers have shown that they can adapt to tighter emission standards by introducing lighter engines, fuel injection, catalytic converters, and other technological improvements. Some experts believe, however, that efforts could be better spent by drastically reducing emissions and promoting alternative energy as well as alternative transportation such as mass transit systems, carpools, and bicycles.

Reformulated Gasoline

Reformulated gasoline (RFG) is gasoline that contains added oxygen. Oxygenation of fuel makes combustion more complete. Incomplete fuel combustion is a major cause of carbon monoxide (CO) emissions. RFG is specially blended to have lower concentrations of certain volatile organic compounds (VOCs) in order to reduce FIGURE 5.19
Vehicle ownership in U.S. over time and for 2001 only in other countries
ozone formation and emissions of air toxins. Although RFG combustion results in lower CO emissions, higher carbon dioxide (CO2) emissions result due to the presence of additional oxygen. The most frequently used oxygenates in RFG are methyl tertiary-butyl ether (MTBE) and ethanol. Fuel ethanol is derived from fermented agricultural products such as corn. RFG results in a lower-octane fuel and usually an increase in price.

The CAA standards that went into effect in 1995 required those areas with the worst polluted air to sell RFG. Denver, Colorado, known for its "brown cloud" of pollution, enacted the nation's first oxygenated fuels program—an entire winter period during which all fuels sold at gas stations were required to have a 3 percent oxygen content. Other areas voluntarily chose to participate in RFG programs. By the early 2000s RFG accounted for more than one-third of all gasoline sold.

Figure 5.20 shows U.S. production and imports of MTBE and fuel ethanol from 1985 to 2002. More than 99 percent of fuel ethanol is produced in the United States, primarily in the corn-growing regions of the Midwest. MTBE sources are approximately 77 percent domestic and 23 percent foreign.

MTBE has historically dominated as the RFG oxygenator of choice. In 2002 it accounted for nearly 63 percent of oxygenate consumption. This value is down from FIGURE 5.20
Oxygenate production and imports (million of gallons), 1985–2003
71 percent in 1998. MTBE demand has fallen, primarily due to environmental concerns. It is very soluble in water and therefore tends to migrate to water supplies. As of August 2003 the U.S. Geological Survey reported that MTBE was found in source water four to five times more often in RFG areas than in non-RFG areas. Several states took steps to decrease or ban the use of MTBE in RFG. (See Table 5.4.) The ban in California is expected to significantly affect MTBE markets as the state accounted for almost one-third of all U.S. consumption during 2003. MTBE bans are expected to greatly increase use of fuel ethanol in RFG.

Beginning in the late 1990s, customer complaints about gasoline prices caused many areas that had voluntarily opted to sell RFG to back out. In the summer of 2000 RFG prices in Milwaukee and Chicago exceeded $2.75 per gallon. These areas used ethanol exclusively in RFG. Even before these price spikes occurred, many states were concerned about the effects of RFG requirements on gasoline prices. In 1999 California asked the federal government for a waiver from the oxygenate requirement. Such a waiver would allow the state to temporarily use non-RFG in case of RFG supply and distribution problems. In 2001 the waiver was denied.

Climbing gasoline prices over the next few years reignited interest in RFG waivers. In April 2004 California resubmitted its waiver request after the Bush administration granted oxygenate waivers to New Hampshire and Arizona. California lawmakers pointed out that the waiver could reduce record high gasoline prices in the state.

Catalytic Converters

Tailpipe catalytic converters are one of the most successful technologies in the history of smog control, eliminating 96 to 98 percent of carbon monoxide (CO) and unburned hydrocarbons and approximately 75 percent of nitrogen oxides.

A catalytic converter is a stainless steel vessel that contains certain chemicals (catalysts) known to affect emission gas reactions. Striving to eliminate pollutants entirely, researchers are perfecting new "preheating" converters.

Overview of state bans on MTBE*

State MTBE ban schedule MTBE consumption* (% of U.S. total)
California MTBE ban starting January 1, 2004 31.7
Colorado MTBE ban started April 30, 2002 0
Connecticut MTBE ban starting October 1, 2003 3.1
Illinois MTBE prohibited by July 2004 0
Indiana MTBE limited to 0.5% by volume, starting July 23, 2004 0
Iowa 0.5% MTBE by volume cap, already in effect 0
Kansas MTBE limited to 0.5% by volume, starting July 1, 2004 0
Kentucky MTBE ban starting January 1, 2006; beginning in January 1, 2004, ethanol encouraged to be used in place of MTBE 0.8
Maine Law merely expresses state's "goal" to ban MTBE; it's not an actual ban. The "goal" is to phase out gasoline or fuel products treated with MTBE by January 1, 2003 0
Michigan MTBE prohibited by June 1, 2003 0
Minnesota All ethers (MTBE, ETBE, TAME) limited to 1/3 of 1.0% by weight after July 1, 2000; after July 1, 2005, total ether ban 0
Missouri MTBE limited to 0.5% by volume, starting July 1, 2005 1.1
Nebraska MTBE limited to 1.0% by volume, starting July 13, 2000 0
New York MTBE ban starting January 1, 2004 7.5
Ohio MTBE ban starting July 1, 2005 0
S. Dakota 0.5% MTBE by volume cap, already in effect 0
Washington MTBE ban starting December 31, 2003 0
*Methyl Tertiary Butyl Ether. Data include MTBE blended into RFG and oxygenated gasoline only. MTBE may also be found in conventional gasoline, but not in significant amounts.
SOURCE: "Table 1. Overview of State MTBE Bans," in Status and Impact of State MTBE Bans, U.S. Department of Energy, Energy Information Administration, Washington, DC, March 27, 2003 [Online] [accessed April 28, 2004]

Converters typically cannot function properly until the car has warmed to a specific temperature, causing emissions to be greatest during the first few miles. The new converters would function as soon as a car is started.

The implementation of catalytic converters in automobiles during the early 1970s was a major reason for conversion from leaded to unleaded gasoline in the United States because the catalysts within the converter were not compatible with lead. Thus the catalytic converter has been directly and indirectly responsible for dramatic reductions in several major air pollutants. In 1998, however, the EPA expressed concerns that catalytic converters were contributing to global warming because they convert many nitrogen-oxygen compounds to nitrous oxide (NO), a common gas associated with global warming. NO levels may increase, at least in part, from the growth in the number of vehicle miles traveled by cars that have catalytic converters.

Government Regulation—Corporate Average Fuel Economy Standards

In 1973 the Organization of Petroleum Exporting Countries (OPEC) imposed an oil embargo that provided a painful reminder to Americans of how dependent the country had become on foreign sources of fuel. Although the United States makes up only 5 percent of the world's population, it consumes approximately one-quarter of the world's supply of oil, much of which is imported from the Middle East. The 1973 oil embargo prompted Congress to pass the 1975 Automobile Fuel Efficiency Act (PL 96-426), which set the initial Corporate Average Fuel Economy (CAFE) standards.

CAFE standards required each domestic automaker to increase the average mileage of the new cars sold to 27.5 miles per gallon (mpg) by 1985. Under CAFE rules automakers could still sell the big, less efficient cars with powerful eight-cylinder engines, but to meet average fuel efficiency rates they also had to sell smaller, more efficient cars. Automakers that failed to meet each year's CAFE standards were required to pay fines. Those who managed to surpass the rates earned credits that they could use in years when they fell below CAFE requirements.

Opponents to CAFE standards complained that the congressional fuel economy campaign would saddle American motorists with car features they would not like and would not buy. They also pointed out that the standards would increase demand for smaller cars, which would in turn raise the number of highway deaths and injuries, limit consumer choice of larger and family-sized vehicles, and place thousands of auto-related jobs at risk.

During the early 1980s automakers became more inventive and managed to keep their cars relatively large and roomy with such innovations as electronic fuel injection and front-wheel drive. Ford's prestigious Lincoln Town Car managed to achieve better mileage in 1985 than its small Pinto did in 1974.

The CAFE standard was lowered during the mid-to-late 1980s and then raised back to 27.5 mpg for 1990 model automobiles. In 2003 the standard remained at 27.5 mpg for automobiles and 20.7 mpg for light trucks, including pickups, minivans, sport utility vehicles (SUVs), and vans. According to the U.S. Department of Transportation (DOT), automobile manufacturers FIGURE 5.21
Vehicle fuel economy by model year, 1975–2003
achieved an average 29.5 mpg fuel economy for model year 2003 cars, thus meeting the standard. Likewise, the average light truck fuel economy was 21.8 mpg, also above the standard.

"Real World" Estimates of Fuel Economy

Fuel economy rates calculated by DOT for comparison to CAFE standards are not the same as rates reported to consumers on new vehicle labels or commonly published by the EPA or U.S. Department of Energy (DOE) in fuel economy guides. DOT CAFE rates are calculated based on laboratory data and take into account credits issued to manufacturers for alternative fuel capabilities and other factors. Rates published by the EPA and DOE are approximately 15 percent lower, as they reflect only actual "real world" experience.

According to the 2003 EPA report Light-Duty Automotive Technology and Fuel Economy Trends: 1975 Through 2003, "real world" estimates of fuel economy for model year 2003 cars and light trucks were 24.8 mpg and 17.7 mpg, respectively. Figure 5.21 shows average "real world" fuel economy rates for model years 1975 through 2003. The combined rate for both cars and trucks has actually decreased since the mid-1980s because of increased demand for light trucks, particularly SUVs. (See Figure 5.22.)

Market Factors

In 1985 cars accounted for nearly 80 percent of new sales. By 2003 their market share had fallen to around 50 FIGURE 5.22
Vehicle sales fraction by vehicle type, 1975–2003
percent. Sales of SUVs and minivans increased dramatically over the same time period. These light trucks have lower fuel economy rates than cars. Also, many states have increased interstate speed limits since the 1980s. This has also lowered overall fuel efficiency.

SUVs and minivans fall under less stringent emissions standards than automobiles because they originated as modifications of light-truck bodies and are classified as trucks. Automakers and buyers of trucks and SUVs oppose tightening restrictions on emissions of these vehicles, although critics contend that new SUVs are more like cars than trucks in design.

U.S. industry officials claim that increasing fuel efficiency is not cost effective. With each mile added in efficiency, the costs to obtain that improvement increase to the point that it is no longer cost effective. This is the same objection that is made, in general, about cleaning up many environmental hazards—that the first and most drastic improvements are the least expensive and thereafter cleanup becomes more costly.

Characteristics of major alternative fuels

Compressed natural gas (CNG) Biodiesel (B20) Electricity Ethanol (E85) Hydrogen Liquified natural gas (LNG) Liquified petroleum gas (LPG) Methanol (M85)
Main fuel source Underground reserves Soy bean oil, waste cooking oil, animal fats, and rapeseed oil Coal; however, nuclear, natural gas, hydroelectric, and renewable resources can also be used. Corn, grains, or agricultural waste Natural gas, methanol, and other energy sources. Underground reserves A by-product of petroleum refining or natural gas processing Natural gas, coal, or, woody biomass
Physical state Compressed gas Liquid Electricity Liquid Compressed gas or liquid Liquid Liquid Liquid
Environmental impacts of burning fuel CNG vehicles can demonstrate a reduction in ozone-forming emissions (CO and NOx) compared to some conventional fuels; however, HC emissions may be increased. Reduces particulate matter and global warming gas emissions compared to conventional diesel; however, emissions NOx may be increased. Electric vehicles have zero tailpipe emissions; however, some amount of emissions can be contributed to power generation. E85 vehicles can demonstrate a 25% reduction in ozone-forming emissions (CO and NOx) compared to reformulated gasoline. Zero regulated emissions for fuel cell-powered vehicles, and only NOx emissions possible for internal combustion engines operating on hydrogen. LNG vehicles can demonstrate a reduction in ozone-forming emissions (CO and NOx) compared to some conventional fuels; however, HC emissions may be increased. LPG vehicles can demonstrate a 60% reduction in ozone-forming emissions (CO and NOx) compared to reformulated gasoline. M85 vehicles can demonstrate a 40% reduction in ozone-forming emissions (CO and NOx) compared to reformulated gasoline.
Energy security impacts CNG is domestically produced. The United States has vast natural gas reserves. Biodiesel is domestically produced and has a fossil energy ratio of 3.3 to 1, which means that its fossil energy inputs are similar to those of petroleum. Electricity is generated mainly through coal fired power plants. Coal is the country's most plentiful, economical, and price-stable fossil fuel. Ethanol is produced domestically and it is renewable. Hydrogen can help reduce U.S. dependence on foreign oil by being produced by renewable resources. LNG is domestically produced and it typically costs less than gasoline and diesel fuels. LPG is the most widely available alternative fuel. Its disadvantage is that 45% of the fuel in the U.S. is derived from oil. Methanol can be domestically produced from renewable resources.
SOURCE: Adapted from data in Custom Alternative Fuels Comparison Chart, U.S. Department of Energy, National Renewable Energy Laboratory, Alternative Fuels Data Center, Golden, CO, May 2004 [Online] [accessed May 1, 2004]

In contrast, for 2005 the European Commission has proposed an ambitious target of 47 mpg for gasoline-driven cars (compared to the current average of 29 mpg) and 52 mpg for diesel-powered cars. It must be noted that, while European countries do not generally legislate fuel efficiency, gasoline in Europe tends to cost more than twice what it does in the United States. That serves as a powerful incentive to European drivers to buy fuel-efficient vehicles.

Although some manufacturers in the United States claim to be able to produce more efficient cars, they also contend that American consumers are not interested in buying them. They believe consumers instead seek features that raise both the size and the price of a car. In essence, manufacturers claim, there is little market for a more efficient vehicle.

Alternative Fuels

The DOE defines alternative fuels as those that are "substantially non-petroleum and yield energy security and environmental benefits." The DOE recognizes all of the following as alternative fuels:

  • compressed or liquefied natural gas
  • coal-derived liquid fuels
  • liquefied petroleum gas
  • alcohol fuels (mixtures that contain at least 70 percent alcohol)
  • bio fuels (fuels derived from biological materials)
  • electricity
  • solar energy
  • hydrogen

Table 5.5 summarizes information for the major alternative fuels related to their physical state, sources, environmental impacts, and availability.

Although these fuels offer advantages, their use may substitute one problem for another. For example, the alcohol fuel methanol reduces ozone formation but increases formaldehyde, a human carcinogen, and is twice as toxic as gasoline if it comes in contact with the skin. Engines require twice as much methanol as gasoline to travel a similar distance. Natural gas reduces hydrocarbons and CO but increases NO5.

The DOE reports that 518,919 alternative fuel vehicles (AFVs) were in use in the United States in 2002, up from 251,352 AFVs in 1992. (See Table 5.6.) Figure 5.23 provides a breakdown of vehicles in use in 2002 by fuel

Alternative-fueled vehicles by type, 1992–2002

Year Liquefied petroleum gases1 Compressed natural gas Liquefied natural gas Methanol, 85 percent2 Methanol, heat Ethanol, 85 percent2 Ethanol, 95 percent2 Electricity Total
Number of vehicles in use
1992 221,000 23,191 90 4,850 404 172 38 1,607 251,352
1993 269,000 32,714 299 10,263 414 441 27 1,690 314,848
1994 264,000 41,227 484 15,484 415 605 33 2,224 324,472
1995 259,000 50,218 603 18,319 386 1,527 136 2,860 333,049
1996 263,000 60,144 663 20,265 172 4,536 361 3,280 352,421
1997 263,000 68,571 813 21,040 172 9,130 347 4,453 367,526
1998 266,000 78,782 1,172 19,648 200 12,788 14 5,243 383,847
1999 R267,833 R91,267 1,681 18,964 198 R24,604 14 6,964 R 411,525
2000 R272,193 R100,738 R2,090 R10,426 R0 R58,621 R4 R11,834 R 455,906
2001 R276,597 R113,835 R2,576 R7,827 R0 R71,336 R0 R17,848 R 490,019
2002P 281,286 126,341 3,187 5,873 0 82,477 0 19,755 518,919
1Vehicles in use represent lower bound estimates, rounded to the nearest thousand.
2Remaining portion is motor gasoline.
R = Revised. P =Preliminary.
Note: Totals may not equal sum of components due to independent rounding.
SOURCE: "Table 10.7. Estimated Alternative-Fueled Vehicles and Fuel Consumption by Type, 1992–2002," in Annual Energy Review 2002, U.S. Department of Energy, Energy Information Administration, Washington, DC, October 2003

type. Most relied on liquefied petroleum gas (55 percent) followed by compressed natural gas (24 percent) and alcohol fuel containing at least 85 percent ethanol (16 percent). A breakdown by ownership is provided in Figure 5.24. A majority (63 percent) of AFVs are in private hands. The remainder are used by federal, state, and local governments.


AFVs cannot become a viable transportation option unless a fuel supply is readily available. Ideally, the infrastructure for supplying alternative fuels will be developed simultaneously with the vehicles. Table 5.7 lists the number of alternative fuel stations in each state as of April 30, 2004. There are 6,230 of these stations around the country. Most of them (64 percent) provide liquefied petroleum gas, followed by compressed natural gas (17 percent) and electricity (13 percent). Together California and Texas account for slightly more than one-third of all the stations.

Many state policies and programs encourage the use of alternative fuels. California, for example, requires the sale of electric vehicles (EVs). This has caused vehicle manufacturers to expedite vehicle research and development. In fact, EVs are already selling in California, and some rental car agencies now offer EVs to customers at prices only slightly higher than gasoline-powered cars.

Market success of alternative fuels and AFVs depends on public acceptance. People are accustomed to using gasoline as their main transportation fuel and it is readily available. As federal and state requirements for alternative fuels increase, so should the availability of such fuels as well as their acceptance by the general public. In the long run, electricity and hydrogen seem the most promising of the alternative fuels for vehicles.


The electric vehicle (EV) is not a new invention. Popular during the 1890s, the quiet, clean, and simple vehicle was expected to dominate the automotive market of the twentieth century. Instead, it quietly disappeared as automakers chose to invest billions of dollars in the internal combustion engine. It has taken a century, but the EV has returned.

The primary difficulty with EVs lies in inadequate battery power. The cars must be recharged often. These vehicles also use lead-acid or nickel-cadmium batteries and have a range of 70 to 100 miles on a single charge. The range is reduced by factors such as cold temperatures, the use of air conditioning, vehicle load, and steep terrain.

In addition, EVs are expensive. Despite their high price, EVs have many advantages. They are relatively noiseless and simple in design and operation. They cost less to refuel and service and have fewer parts to break down. Their owners are likely to spend less time on maintenance and, if they recharge at home, will rarely have to go to the service station. These time-saving features have real value in the busy world of the twenty-first century. Over time the cost gap between cars that pollute and EVs that do not will narrow. With advances in battery development, the gap could close entirely.

Automobile industry experts believe EVs will assume a "second car" role for commuters and for short trips, much like the microwave oven has become an addition to, rather than a replacement for, conventional ovens for cooking.


Hydrogen is the most simple naturally occurring element and can be found in materials such as water, natural gas, and coal. For decades advocates of hydrogen have promoted FIGURE 5.23
Alternative fuel vehicles in use by fuel type, 2002
it as the fuel of the future—abundant, clean, and cheap. Hydrogen researchers from universities, laboratories, and private companies claim that their industry has already produced vehicles that could be ready for consumers if problems of fuel supply and distribution could be solved. Other experts contend that economics and safety concerns will limit hydrogen's wider use for decades.

In 2002 the DOE formed a government-industry partnership called Freedom Cooperative Automotive Research (FreedomCAR). The goal of FreedomCAR is to develop highly fuel-efficient vehicles that operate using hydrogen produced from renewable energy sources. Industrial partners in the venture include Ford, General Motors, and Daimler-Chrysler. FreedomCAR research takes place at facilities operated by the DOE's National Renewable Energy Laboratory in Golden, Colorado.

In his 2003 State of the Union Address, President George W. Bush announced the creation of the Hydrogen Fuel Initiative (HFI). This $1.2 billion program is designed to develop the technology needed for commercially viable hydrogen-powered fuel cells by the year 2020. Fuel cells designed for transportation vehicles and home/business use are to be developed. The HFI has three primary missions as part of its goals:

  • Lower the cost of hydrogen production to make it cost effective with gasoline production by the year 2010 FIGURE 5.24
    Ownership of alternative fuel vehicles, 2002
  • Develop hydrogen fuel cells that provide the same vehicle range (at least 300 miles of travel) as conventional gasoline fuel tanks
  • Lower the cost of hydrogen fuel cells to be comparable in cost with internal combustion engines


Many experts believe that the most feasible solution in the near future is to produce vehicles that use a combination of gasoline and one of the alternative fuel sources. These are called hybrid vehicles. Figure 5.25 depicts a hybrid automobile that relies on a small internal combustion engine and electricity (from batteries).

As of early 2004 there are three hybrid automobiles for sale in the United States. They are the Honda Insight, Toyota Prius, and Honda Civic Hybrid. The DOE calls them Advanced Technology Vehicles. Table 5.8 compares sales and technical specifications for the three models. With fuel efficiencies in the range of 47–57 mpg, these cars provide roughly twice as many miles per gallon of gasoline than conventional cars on the market. Manufacturers continue research on hybrid cars, which they hope will eventually satisfy American tastes and pocketbooks and provide even greater fuel efficiency.


The Energy Policy Act of 1992 (PL 102-486), passed in the wake of the 1991 Persian Gulf War, required that federal

Alternative fuel stations by state and fuel type, as of April 2004

State CNG E85 LPG ELEC BD HY LNG Totals by state
Alabama 9 0 77 34 0 0 1 121
Alaska 0 0 9 0 0 0 0 9
Arizona 27 1 112 54 3 1 8 206
Arkansas 4 0 85 0 0 0 0 89
California 194 1 352 514 17 5 35 1,118
Colorado 35 9 85 6 8 0 0 143
Connecticut 25 0 29 5 1 0 0 60
Delaware 3 0 4 0 4 0 0 11
Dist. of Columbia 2 0 0 0 0 0 0 2
Florida 44 0 154 3 1 0 0 202
Georgia 65 0 54 87 2 0 0 208
Hawaii 0 0 7 11 3 0 0 21
Idaho 9 1 33 0 2 0 2 47
Illinois 22 13 92 0 3 0 0 130
Indiana 23 0 54 0 1 0 3 81
Iowa 0 11 44 0 1 0 0 56
Kansas 6 2 67 0 6 0 1 82
Kentucky 1 7 27 0 0 0 0 35
Louisiana 11 0 45 0 0 0 0 56
Maine 0 0 15 0 2 0 0 17
Maryland 20 3 28 1 7 0 0 59
Massachusetts 13 0 44 41 2 0 0 100
Michigan 20 4 138 5 9 0 0 176
Minnesota 5 87 58 0 1 0 0 151
Mississippi 0 0 34 0 0 0 0 34
Missouri 8 7 151 0 1 0 0 167
Montana 5 2 41 0 1 0 1 50
Nebraska 1 5 27 0 1 0 0 34
Nevada 17 0 34 0 6 1 0 58
New Hampshire 2 0 30 12 3 0 0 47
New Jersey 18 0 25 0 0 0 0 43
New Mexico 13 2 81 0 1 0 0 97
New York 55 0 67 11 0 0 0 133
North Carolina 9 2 75 6 22 0 0 114
North Dakota 4 2 18 0 0 0 0 24
Ohio 38 2 77 0 2 0 0 119
Oklahoma 57 1 99 0 0 0 0 157
Oregon 16 0 49 4 5 0 1 75
Pennsylvania 51 0 105 0 1 0 1 158
Rhode Island 6 0 7 2 0 0 0 15
South Carolina 4 1 62 0 2 0 0 69
South Dakota 0 9 26 0 0 0 0 35
Tennessee 2 1 60 0 0 0 0 63
Texas 40 0 969 6 1 0 6 1,022
Utah 65 2 38 0 0 0 1 106
Vermont 1 0 15 11 0 0 0 27
Virginia 22 1 58 11 6 0 2 100
Washington 22 1 83 6 14 0 0 126
West Virginia 5 0 9 0 0 0 0 14
Wisconsin 22 10 77 0 1 0 0 110
Wyoming 14 1 36 0 2 0 0 53
Totals by fuel: 1,035 188 3,966 830 142 7 62 6,230
Notes: CNG = Compressed natural gas; E85 = 85% ethanol; LPG = propane; ELEC = electric; BD = biodiesel; HY = hydrogen; LNG = Liquefied natural gas.
SOURCE: "Alternative Fuel Station Counts Listed by State and Fuel Type," in Alternative Fuels Data Center, U.S. Department of Energy, National Renewable Energy Laboratory, Alternative Fuels Data Center, Golden, CO, April 30, 2004 [Online] [accessed April 30, 2004]

and state governments and fuel provider fleet owners increase the percentages of vehicles powered by alternative fuels. The fleet requirements affect those who own or control at least 50 vehicles in the United States and fleets of at least 20 vehicles that are centrally fueled (or capable of being centrally fueled) within a metropolitan area of 250,000 or more.

Diagram of hybrid-electric vehicle

In fiscal year 2001 the federal government purchased 23,325 fleet vehicles. The vast majority (81 percent) were gasoline powered. Just over 2,500 of the vehicles were diesel powered. Another 1,870 of the vehicles used alternative fuels. Most of these vehicles were powered by ethanol-85.

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