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Conserving Energy and Preserving the Environment: The Role of Public Transportation By Robert J. Shapiro, Kevin A. Hassett and Frank S. Arnold July 2002 Download a PDF copy of the report. About the Authors Dr. Robert J. Shapiro is Managing Director of Sonecon, LLC, a non-resident Fellow of the Brookings Institution and the Progressive Policy Institute, Economic Counselor to the U. S. Conference Board, and a director of the Axson-Johnson Foundation in Sweden and the Center for International Political Economy in New York. From 1997 to 2001, Dr. Shapiro was Under Secretary of Commerce for Economic Affairs. In that position, he oversaw economic policy for the Commerce Department and directed the Nation's major statistical agencies, including the Census Bureau as it conducted the decennial Census. Prior to that post, he was co-founder and Vice President of the Progressive Policy Institute, and principal economic advisor to William Clinton in his 1991-1992 presidential campaign. He also has been Legislative Director for Senator Daniel P. Moynihan and Associate Editor of U. S. News & World Report. Dr. Shapiro has been a Fellow of Harvard University and Fellow of the National Bureau of Economic Research. He holds a Ph. D. and M. A. from Harvard University, an M. Sc. from the London School of Economics and Political Science, and an A. B. from the University of Chicago. Dr. Kevin A. Hassett is a Resident Scholar of the American Enterprise Institute, where he focuses on macroeconomics, public finance and tax policy. He is also the author or co-author of four books, including the forthcoming Bubbleology: The Remarkable Science of Stock Market Winners and Losers, and numerous articles. Dr. Hassett was chief economic adviser to Senator John McCain in his 2000 presidential campaign. Previously, he was a Senior Economist at the Board of Governors of the Federal Reserve System and Associate Professor of economics and finance at the Columbia University Graduate School of Business. He also has served as policy consultant to the Treasury Department during the administrations of Presidents George Bush and William Clinton. Dr. Hassett holds a Ph. D. from the University of Pennsylvania and a B. A. from Swarthmore College. Dr. Frank S. Arnold is President of Applied Microeconomics, Inc. He is also a columnist for The Environmental Forum, published by the Environmental Law Institute, and a consulting economist to ICF Incorporated. Dr. Arnold is a nationally recognized expert on environmental economics, including such areas as the analytic methods used to conduct EPA regulatory and economic impact analyses, life cycle assessment, environmental enforcement, and global change and energy conservation. Prior to founding Applied Microeconomics, Inc., Dr. Arnold was Vice President and Senior Economist for ICF Incorporated and a Visiting Scholar at the Environmental Law Institute. He has been a Fellow of the National Bureau of Economic Research, the National Science Foundation, and the Institute for Humane Studies. Dr. Arnold holds a Ph. D. from Harvard University and a B. A. from the University of Virginia. * This report was commissioned by the American Public Transportation Association. TABLE OF CONTENTS The role of transportation in our nation's energy consumption and environmental quality is immense. Americans use more energy and generate more pollution in their daily lives than they do in the production of all the goods in the economy, the operations of all commercial enterprises, or the running of their homes. Any serious effort to reduce our dependence on foreign oil and make significant environmental progress must address the way Americans travel. The vital role of public transportation in improving energy efficiency and the environment is often under-appreciated. With its fuel and pollution advantages, increased use of transit offers the most effective strategy available for reducing energy consumption and improving the environment without imposing new taxes, government mandates, or regulations on the economy or consumers. Public transportation needs to be an essential element in sound national energy and environmental policies. Potential threats to the supply and price of foreign oil as a result of terrorism, conflicts in the Middle East, and OPEC decisions underscore the need for a public transportation strategy that reduces our nation's dependence on imported oil. Likewise, ongoing efforts to reduce harmful emissions from our air can be more effective when they include ways to increase use of public transportation. "Conserving Energy and Preserving the Environment: The Role of Public Transportation" demonstrates that traveling by transit, per person and per mile, uses significantly less energy and produces substantially less pollution than comparable travel by private vehicles. The findings provide clear and indisputable evidence that public transportation is saving energy and reducing pollution in America today --and that increased usage could have an even greater impact in the future. Current Benefits At our current levels of use, the study found public transportation is reducing Americans' energy bills and keeping the air cleaner. For example: Energy savings from public transportation contribute to our national and economic security by making America less dependent on foreign oil or on new sources for drilling.
Even at current rates of usage, public transportation produces large environmental benefits.
Potential, Achievable Benefits As great as the current advantages are, far greater energy and environmental benefits could be derived through increased use of public transportation. Based on our findings, the study concludes that greater use of public transportation offers the single most effective strategy currently available for achieving significant energy savings and environmental gains, without creating new government programs or imposing new rules on the private sector. If Americans increase their use of public transportation, the study found dramatic benefits in energy conservation and a healthier environment. For example, if Americans used public transportation at the same rate as Europeans -- for roughly ten percent of their daily travel needs -- the United States would:
If Americans used public transportation at the same rate as Canadians --for roughly seven percent of their daily travel needs --the United States would:
Even modest increases in the use of public transportation would produce great reductions in hazardous pollution in congested areas where pollution now poses the greatest risk.
Achieving a genuine measure of energy independence and cleaner air by investing in our public transportation systems has significant economic advantages. While this study measured current and potential benefits of public transportation, the findings lead us to believe that achieving greater energy savings and environmental gains by significantly increasing the passenger loads would be less costly than continuing to expand the fleet of private vehicles, build and maintain more roads and highways to accommodate them, and absorb the rising energy, environmental and congestion expenses of this approach. An Attainable Goal for Americans Increasing Americans' use of public transit is an achievable goal. In the early 20 th century, America led the world in mass transit development and use. Recent data suggest that a transit renaissance may be underway in the United States. Specifically, the study points to the following facts: 1) since 1995, use of public transportation has grown sharply and faster than the use of private vehicles; 2) passenger miles ridden on public buses and rail systems have grown faster than the passenger miles ridden in private automobiles, SUVs and light trucks; and 3) public transportation ridership has grown at a faster rate than air travel in recent years. "Conserving Energy and Preserving the Environment: The Role of Public Transportation" concludes that making much greater use of public transportation may be the most effective strategy to sharply reduce our dependence on foreign oil and make historic strides in environmental quality. The study argues that these results can be achieved if we make public transportation a vital part of our nation's energy and environmental policies. Conserving Energy and Preserving the Environment: The Role of Public Transportation As the United States strives to achieve greater energy efficiency and independence and to improve the environment, the role of transportation has become paramount. America consumes more energy and produces more pollution in mobility and travel than in any other activity. It follows that any serious effort to reduce our dependence on foreign oil and make significant additional progress on the environment must address the way Americans travel. This study examines the role of public transportation in conserving energy and reducing pollution. The data show that traveling by public transportation, per person and per mile, uses significantly less energy and produces substantially less pollution than comparable travel by private vehicles. We find that increasing the role of public transportation can provide the most effective strategy available for reducing energy consumption and improving the environment without imposing new taxes and government regulations on the economy or consumers. Americans highly value their mobility and with good reason. Our communities, the economy and much of our lives are organized around our ability to travel easily and efficiently from home to work or school, to shop or play, to receive medical care or just for the sheer pleasure of traveling. This freedom has certain costs that accompany its many benefits. Vehicles, public and private, have to be purchased and operated; roads must be built and maintained; laws must be enforced so many people can travel at the same time; and hundreds of thousands of accidents inevitably occur. The most fundamental costs of mobility, however, involve the energy required to move people and goods over any distance, and the pollution released as this energy is burned. As shown in Table 1, in 2000 Americans consumed more energy moving from place to place than industry used to produce all of its goods. All forms of transportation also consumed almost four times the energy of all residential uses and more than six times the energy of all commercial uses. Moreover, petroleum products provide virtually all of the fuel used for transportation, while other sectors use more diverse, efficient, and environmentally friendly sources of energy. Table 1.
Energy and environmental costs are built into all forms of mobility by mechanical means, but personal and political choices can reduce the fuel and pollution "overhead" associated with a given level of mobility. The primary approach for lowering these costs involves developing and using technologies that reduce either the fuel required to move people and goods, or the amount of pollution associated with burning that fuel. The most prominent regulatory strategies developed to advance this approach are the Corporate Average Fuel Efficiency (CAFÉ) and auto-emission standards for private automobiles. The non-regulatory strategy with the greatest potential for achieving the same results is greater use of public transportation, because on a per-person, per-mile basis, public transportation is much more energy efficient and much less polluting than private automobiles.
The most recent data show that the current use of public transportation is a major source of energy savings.
Over the 42.5 billion passenger miles traveled on public transportation in 1998, the energy benefits add up to nearly than 107 trillion British thermal units (Btus). (2) As we will show, these energy benefits are comparable to the energy consumed by various manufacturing industries. For example, the energy saved through the use of public transportation is equivalent to half of the energy used to manufacture computers and electronic equipment in America. These energy savings are also equal to 99 percent of the energy used by the beverage and tobacco industries, and more than four times all the energy used to manufacture apparel. Finally, these energy benefits are equivalent to about one-fourth of the energy used to heat American homes in 1997 (the most recent data). (3) These savings carry clear significance for our national and economic security. The United States is increasingly dependent on oil from the Middle East, at a time when dangers from Saddam Hussein, the war against terrorism, and the Israeli-Palestinian conflict all threaten to interrupt the supply of OPEC oil or sharply increase its price. Greater use of public transportation can offer a powerful conservation strategy that could substantially reduce our dependence on imported oil. There is no other technology or approach other than increased use of public transportation that, for every trip it is used, has the energy impact of nearly doubling the fuel efficiency of automobiles. Table 2 shows that the energy savings attributable to public
transportation in 1998 are equivalent to almost 860 million gallons
of gasoline, or more than 45 million barrels of imported oil; the energy
saved by the use of public transit in 1999 was equal to almost 890 million
gallons of gasoline and nearly 47 million barrels of oil.
Put another way, the current use of public transportation reduces our energy dependence by the equivalent of nearly one month's imports from Saudi Arabia, which ran a little less than 1.5 million barrels per day in 1998 and 1999, and currently run about 1.6 million barrels per day. These energy savings from public transit are also equal to two-to-three weeks of imports from the entire Persian Gulf.
The environmental benefits from using public transportation, compared to private automobiles (including SUVs and light trucks), are also highly significant. Here, we will examine the impact of public transportation, versus private automobiles, on emissions of four major air pollutants. (4) The first two are volatile organic compounds (VOCs) and nitrogen oxides (NOx), which combine with sunlight to form ozone, or smog. Smog is a serious irritant that can cause coughing, choking, and stinging eyes, damage lung tissues, and exacerbate respiratory illnesses. Children are especially susceptible to the harmful effects of VOCs and NOx in smog, and even healthy adults usually feel its effects over time. Another important pollutant examined here is carbon monoxide (CO), a poisonous gas that reduces the body's ability to transport oxygen to organs and tissues, and interferes with learning. Elderly people, children and adults with respiratory conditions are particularly vulnerable to the effects of CO exposure. These three pollutants pose the greatest risks to people living in urban and close-in suburban areas, where smog and CO concentrations are highest and public transportation systems are most highly developed. Greater use of public transportation, therefore, would reduce hazardous pollution in precisely those areas where it now presents the greatest risks. In addition to these three pollutants, the analysis also covers the impact of public transportation on emissions of carbon dioxide (CO2), a major greenhouse gas that contributes to climate change. The data in Table 3 show that travel on public transportation produces much less dangerous pollution than comparable travel by private automobile, SUV, and light truck. Table 3. Emissions by Public Transit and by Replacement Use of Private Vehicles Metric Tons, 1999
This environmental impact equals or exceeds the dimensions used under Federal guidelines to identify major regulations. The Office of Management and Budget (OMB) currently defines as a "major rule" any environmental (or other) regulation that imposes a cost of $100 million or more a year. The Environmental Protection Agency (EPA) estimates that under its current emission standards regulation, it costs business and consumers between $1,300 and $2,000 per metric ton to reduce NOx and VOCs. (5) In 1999, for example, the use of public transportation reduced NOx and VOC emissions by nearly 100,000 metric tons, implicitly saving between $130 million and $200 million a year in regulatory costs. The environmental benefits from the use of public transportation compare favorably with the results of decades of regulation of once highly polluting industries. As this report will show, the reductions in CO emissions attributable to the use of public transit are equal to nearly three-fourths of all CO emissions by chemical manufacturers. These reductions in CO emissions are also equal to more than half the CO produced by the metal processing sector, and 60 percent more than the CO emissions by the electric utility industry. (6) The NOx benefits of public transportation are also equal to more than one-third of the NOx emissions of American oil and gas producers, and nearly half of the NOx emissions from all industrial uses of coal. (7) Similarly, the reductions in VOCs attributable to the use of public transportation are equal to about half of all VOC emissions from the dry cleaning industry, a major source of this pollutant, and just under 45 percent of the VOCs emitted by the industrial use of coal. The energy savings and environmental benefits derived from public transportation could be much greater, if Americans used public transit more frequently. In the early 20 th century when cities were growing rapidly, public and private streetcar and bus lines were established across the country, and America led the world in mass-transit development and use. (8) Since World War II, private automobiles have become the dominant means of short-distance travel, even as public transit assumed a larger role many other countries. Over the last several decades, for example, the number of privately-owned vehicles has grown more than twice as fast as the population. (9) As shown in Table 4, in 1998 public transportation logged 42.7 billion passenger miles, compared to nearly 3.9 trillion passenger miles in private automobiles, SUVs, and light trucks. Table 4. Passenger Miles and Shares by Mode of Transportation, 1998 (10)
After more than a decade in which the total number of passenger miles traveled in private vehicles grew significantly faster than public transportation passenger miles, the most recent data indicate a turn-around: Since 1995, the use of public transit has grown both sharply and faster than the use of private vehicles. As shown in Table 5, use of public rail systems has increased even faster than the use of SUVs and light trucks, the vehicles that dominated the growth in transportation in the 1980s and early 1990s. Moreover, public bus use has grown faster than automobile use, and nearly as fast as SUV and light-truck use. Table 5. Changes in Passenger Miles, 1980-1990, 1990-1995, and 1995-1998 (11)
Public transportation has also grown at a faster rate than air travel in recent
years. From 1995 to 1998, the number of trips taken on public buses grew 11.4
percent, and the number of trips taken on public-rail systems increased 16.1
percent: Together, the number of trips on public transportation
increased 13 percent from 1995 to 1998. 12 Over the same
period, the number of domestic airline passengers increased
11.9 percent, and the number of airline departures grew only 2.7 percent. (13)
Given its high energy efficiency and low polluting, public transportation offers the single largest untapped source of energy savings and environmental gains available to the United States. Throughout much of Europe, people use public transportation for about 10 percent of their daily travel needs. (14) There, governments have long used tax, planning, and regulatory policies to encourage the use of public transportation and protect their urban centers from automobile congestion. Virtually all European governments have also long provided extensive capital and operating assistance to their bus and rail systems. We will see that if Americans used public transportation at the same rate as Europeans - if a little more than ten percent of those who currently use private automobiles shifted to public transportation, or everyone used public transit for about ten percent of their daily travel needs -- the United States could be virtually energy independent from Saudi Arabia. The energy savings at that level of public- transit use would be equal to one-quarter of all energy use in the commercial sector in 2000. 15 This report shows that if just five percent of Americans left their cars at home and used public transportation, or if everyone used public transit five percent of the time, it would reduce CO pollution by more than all of the CO emitted by the chemical manufacturing sector and all metal processing plants. (16) If ten percent of Americans switched to public transit or everyone used public transit for ten percent of their daily travel needs, the United States would achieve more than one-quarter of the CO2 reductions mandated by the Kyoto Treaty, without increasing gas taxes or imposing regulatory restrictions on business. It would also reduce NOx pollution by more than the NOx produced by all industrial uses of coal, and produce environmental benefits equivalent to more than all the VOCs emitted by the chemical manufacturers and all oil and gas production. (17) At one time, such levels of transit use, or even greater, were common. In 1920, the average person in an American city used public transportation about 250 times a year. (18) This widespread reliance on public transport declined with the rapid increase in automobile ownership in the 1940s and 1950s. With growing use of faster and more flexible means of private transportation, residential and commercial development spread farther from the established transit lines along which center cities and many early suburbs had formed. Today, with local land use planning generally uncoordinated with regional transportation planning, development continues to unfold even farther from existing public transportation corridors. (19) Achieving much greater energy savings and environmental benefits by significantly increasing the passenger loads of existing public transportation systems would require modest new investments, at a much lower cost than would be required to produce comparable energy and environmental benefits by other means. Achieving a genuine measure of energy independence and markedly cleaner air by raising our public transportation use to European levels would require significant financial commitments, as well as changes in other areas such as land-use planning and the way many public transportation systems operate. The long-term price tag for substantially expanding the country's public transportation infrastructure, especially rail systems, would be less than the cost of continuing to expand the country's fleet of private vehicles, build and maintain more roads and highways to accommodate them, and absorb the rising energy, environmental, and congestion costs of this approach. Given the limits and risks to our energy supply and the threats to the environment, relying for the long-term on private cars, SUVs, and light trucks for 99 percent of all daily transportation needs will be unsustainable. II. The Energy Savings from the Use of Public Transportation The consumption of energy by private automobiles in
the United States truly dwarfs energy consumption by public transportation
systems, as would be expected based on their relative use. In 1998,
public transit consumed about 800 million gallons of gasoline, diesel
and other fossil fuels, plus about 5.1 billion kilowatt-hours (kWh)
of electrical power. By contrast, private cars consumed about 123 billion
gallons of gasoline, diesel, and other fuels. (20)
Converting these various forms of fuel to Btus makes the comparison
clear, shown in Table 6. Table 6. Energy Consumption, Private and Public Transportation, Btus, 1998 (21)
Table 7. Fuel Consumption by Mode of Public Transport, 1998 22
Table 8. Vehicle Miles and Passenger Miles, By Mode of Public Transport, 1998 (25)
Table 9. Average Passenger Load for Public and Private Vehicle Transportation, 1998 (26)
Increasing the average passenger loads of buses, trains or private vehicles would directly raise energy efficiency, because carrying additional passengers would increase the energy consumed only marginally, if at all. One difference which points to public transportation's greater potential for energy savings, compared to private vehicles, is that shifting passengers from private vehicles to public transportation would not require additional trips by public transit, while shifts in the other direction often would mean more automobile trips. Another reason public transportation is nearly twice as energy efficient as private automobiles is that about half of the public transportation vehicle miles are traveled using trains, which not only carry many people, but also use more efficiently provided electricity for power. As shown in Table 10, the average energy use for public transportation is 2,740.8 Btus per passenger mile, which about half the some 6,348.2 Btus per passenger mile used by automobiles. The most energy-efficient mode of public transportation, electrically powered trains, requires only about 1,000 Btus per passenger mile. Table 10. Energy Efficiency of Public Transportation, by Fuel Source Per Mile and Per Passenger Mile, 1998
The most accurate way to calculate the precise energy savings from the use of public transportation involves a number of steps. Having determined the distance traveled and fuel consumed by each mode of public transit (Tables 7 and 8), and the marginal fuel efficiency or Btu per vehicle mile and Btu per passenger mile (Table 10), we perform a simple thought experiment. We hypothesize that public transportation is no longer available, and the 42.5 billion passenger miles that occurred on public transit in 1998 have to take place in private automobiles. We calculate how many vehicle miles in private automobiles, SUVs and light trucks it would take to replace the 42.5 billion passenger miles provided by public transportation. Next, we determine how much fuel these private vehicles would use to meet the travel needs served by public transit. The difference between that fuel and the fuel used by public transportation gives us an accurate measure of the net energy and conservation benefits of public transportation. The first step in running this thought experiment involves calculating how many additional vehicle miles would have to be traveled in private vehicles, to account for the 42.5 billion passenger miles traveled on public transportation in 1998. As just noted, one critical difference between private automobiles and public transportation is their different passenger loads. According to the most recent Nationwide Personal Transportation Survey, 27 driving in America remains a fairly solitary activity: Roughly 70 percent of all automobile trips involve a driver and no passengers, and about 19 percent more involve the driver and only one passenger. Of the remaining 11 percent of automobile trips, just over six percent involve a driver and two passengers, and less than five percent involve a driver and three or more passengers. Using these data, we can distribute the 42.5 billion passenger
miles from public transportation to the four different passenger-load
categories, and calculate the additional private vehicle miles that
would have to be traveled if there were no public transportation. If
private vehicles replaced all public transportation, and its passengers
were distributed according to current passenger loads in private automobiles,
the 42.5 billion passenger miles on public transportation would require
35.1 billion vehicle miles in private automobiles. Table 11. Private Vehicle Miles Driven in Shift from Public to Private Transportation
Table 12. Vehicles Miles and Fuel Efficiency of Private Vehicles, 1998
Based on the number of automobiles and the number of
SUVs and light trucks actually on the road, and the Btus burned per
mile by each category, we calculate a weighted average that represents
the average energy consumed every mile by all private vehicles: 6,348.2
Btus per vehicle mile. Using this value, we can easily calculate the
total energy needed to travel 35.1 billion vehicle miles: Transporting
all the passengers from public transportation in private vehicles, in
the same proportions and passenger loads as everyone else, would consume
about 223.2 trillion Btus. Now we can determine the energy consumed
per passenger mile by the private vehicles that replace public transit
in our thought experiment: 5,254.8 Btus per passenger mile. Table 13. Values for Determining the Energy Benefits of Public Transportation, 1998
Every passenger mile traveled on public transportation saves 2,514 Btus. Based on 1998 data, public transportation saves more than 105 trillion Btus (106,782,895,800,499) per year. Even though public transportation currently accounts for just 1.1 percent of all the passenger miles traveled in America, its energy benefits are large. The 106.8 trillion Btus in energy savings in 1998 are equivalent to more than 855 million gallons of gasoline, or more than 45 million barrels of oil --a half-month's supply of oil imports from the Persian Gulf. As noted earlier, the energy savings by 1999 amounted to the equivalent of almost 890 million gallons of gasoline or nearly 47 million barrels of oil. These benefits compare favorably with energy use by various energy-intensive industries. For example, the energy savings from public transportation are equal to more than twice the energy consumed by the apparel industry, and half the energy burned by the paper pulp industry or by all manufacturers of computer and electronic equipment. Table 14. Energy Savings from the Use of Public Transportation versus Energy Consumed by Various Industries, 1998, Trillion BTUs (28)
* * * III. The Environmental Benefits from the Use of Public Transportation Public transportation also offers the largest opportunity and the most efficient means for making major strides in environmental quality without direct government regulation, especially in the urban and densely populated suburban areas with the worst pollution. The direct environmental benefits of public transportation come primarily from two factors. First, as we have now established, public transportation systems burn less fuel on a per person/ per mile basis and therefore produce less pollution. Second, the diesel fuel and electrical power used in public transportation systems are less polluting, unit-by-unit, than the gasoline used in most private automobiles, SUVs, and light trucks. As noted earlier, this analysis focuses on four major pollutants. The first two are volatile organic compounds (VOCs) and nitrogen oxides (NOx), which combined with sunlight produce ozone or smog. Ozone can irritate people's respiratory systems and eyes, damage their lungs, and exacerbate many respiratory conditions. In addition to VOCs and NOx, this analysis examines emissions of carbon monoxide (CO), a poisonous gas that hampers the body's ability to transfer oxygen to organs and tissues, and carbon dioxide (CO2), a greenhouse gas that is a major contributor to climate change. As before, the focus here is on buses and rail systems within metropolitan areas. Of more than 3.1 billion vehicle miles covered by public transportation systems in 1999, just about two-thirds occurred on buses, which run primarily on diesel fuel. The remaining one-third occurred on commuter, light and heavy rail systems, mostly powered by electricity. Table 15. Public Transportation Vehicle Miles by Mode, 1999 (30)
The next step in calculating the environmental benefits
of public transportation draws on data collected and issued by the Environment
Protection Agency (EPA) and the Department of Transportation. First,
we use the emissions per mile produced by fossil-fuel powered vehicles,
including buses and diesel-powered trains. Diesel-powered rail systems
produce roughly four times as much emissions per mile as diesel
buses, only because they require much larger engines to carry many more
passengers. Table 16a. Emissions by Buses and Diesel-Powered Trains, Grams/Vehicle Mile, 1999 31
Next, we calculate the emissions produced by electricity-powered rail systems,
in grams per million-kilowatt-hour (MKWH). We start with all the pollution in
grams produced by electric utilities, divide that by the million-kilowatt-hours generated by utilities, to arrive at electric utility pollution in grams/ MKWH,
and multiply that result by the million-kilowatt-hours used by public rail systems. The result is presented in Table 16b: Table 16b. Emissions by Electricity-Powered Rail Systems, Grams/ MKWH, 1999 32
Now, we can easily calculate the total pollution produced by public transportation in 1999: It is the sum of the emissions per-vehicle-mile in grams for fossil-fuel powered systems (Table 16a), times the vehicle miles traveled by these systems (Table 15), plus the emissions per-vehicle-mile for electrically-powered systems, in grams per MKWH (Table 16b), times the MKWH of electricity consumed by these public transit systems. The results have been converted to a common measure, metric tons, and presented in Table 17: Table 17. Pollution Emissions by Public Transportation, by Mode, Metric Tons, 1999
As in our analysis of the energy savings produced by use of public transportation, we next hypothesize that public transit is unavailable and all the passenger miles traveled on public transportation must instead be satisfied by travel in private automobiles, SUVs, and light trucks. The difference between the pollution produced by public transportation and the pollution that would be produced if all public transportation riders used private vehicles provides an accurate measure of the environmental benefits of public transportation. To calculate this benefit, we next turn to data from the EPA and the Department of Transportation on the pollution produced, per mile, by private automobiles, SUVs and light trucks. Using other data on the total numbers of private vehicles on the road in each of the two categories (automobiles and SUVs/ light trucks), we ascertain a weighted average for the pollution emitted by private vehicles, overall: Table 18. Pollution Emissions by Private Vehicles, Grams Per Vehicle Mile, 1999 33
These data illustrate the serious environmental consequences of Americans' increasing preference for SUVs and light trucks, compared to automobiles, and the consequent growing importance of public transportation in improving environmental quality. Compared to automobiles, these larger vehicles emit, per-mile, 33 percent more volatile organic compounds, 24 percent more carbon monoxide, 30 percent more nitrogen oxides, and 26 percent more carbon dioxide. While SUVs and light trucks, on average, do carry marginally more passengers than automobiles - 1.64 people, compared to 1.59 for conventional automobiles -- the larger vehicles produce nearly 30 percent more smog and 26 percent more global-warming gases than automobiles. Our next step involves calculating the number of vehicle miles that would have to be driven in automobiles and the larger passenger vehicles to accommodate the 44.1 billion passenger miles traveled on public transportation in 1999. To distribute the riders on public transportation to private vehicles, we begin with the distribution of occupants, or passenger load, for private vehicle trips --the percentages of all private-vehicle miles driven by drivers alone, drivers with one passenger, drivers with two passengers, and drivers with three or more passengers. Multiplying these percentages by the total passenger miles distributes the passenger miles by passenger load, and dividing those results by the number of occupants in each category produces the number of private-vehicle miles needed required to replace the passenger miles ridden on public transportation. If public transportation was unavailable, its riders would have to drive or be driven 36.4 billion miles in private vehicles, in order to replace the 44.1 billion passenger miles traveled on public buses and rail systems in 1999: Table 19. Private Vehicle Miles Driven in Shift from Public Transportation, 1999 (34)
The difference between that pollution produced by the current use of public transportation (Table 17), and the pollution produced by private vehicles traveling the 36.4 billion miles required to replace the current use of public transit, presented in Table 20, provides an accurate measure of the environmental benefits of public transportation. Table 20. Environmental Benefits of Public Transportation: Pollution Produced by Private Vehicles and Public Transportation Over the Vehicle Miles Traveled on Public Transportation, Metric Tons, 1999
Public transportation produces about 90 percent less volatile organic compounds, more than 95 percent less carbon monoxide, and almost 50 percent less nitrogen oxides and carbon dioxide than private vehicles would if all the people who currently ride public transportation had to use automobiles, SUVs, and light trucks for the same travel. Even though public transportation accounts for a small share of all the passenger miles traveled in America, it produces large environmental benefits. The reductions in the emissions of volatile organic compounds from the use of public transportation, for example, are equal to roughly half the VOCs emitted by all dry cleaning operations in the country, and the carbon monoxide reductions are about 60 percent greater than the CO emitted by all electric utilities. The use of public transportation also reduces pollution by amounts that compare favorably with the pollution emitted by four high-polluting industries. As Table 21a shows, public transportation reduced potential VOC emissions in 1999 by more than 77,000 tons, equivalent to 10.4 percent of the combined VOC emissions from the four industry groups. The reductions in VOCs attributable to public transportation also exceeded the VOCs emitted by the metals processing industry and were equivalent to more than 11 times the VOCs produced by the industrial use of coal. Table 21a. Emissions of Volatile Organic Compounds (VOCs): Benefits of Public Transportation versus Emissions by Industries, 1999, Short Tons 35
Similarly, public transportation reduced potential
CO emissions in 1999 by more than 820,000 tons, or the equivalent of
nearly 30 percent of the total CO emissions from all four industry groups.
The reductions in CO emissions attributable to public transportation
are also equal to more than 75 percent of the CO produced by U. S. chemical
manufacturers, and thirty times the CO emissions of oil and gas producers
(see Table 21b, below). Table 21b. Emissions of Carbon Monoxide (CO): Benefits of Public Transportation versus Emissions by Industries, 1999, Short Tons 36
Table 21c. Emissions of Nitrogen Oxides (NOx): Benefits of Public Transportation versus Emissions by Industries, 1999, Short Tons (37)
Industry comparisons are less useful in evaluating the impact of public transportation on CO2 emissions. Virtually all CO2 pollution in the United States, or 98 percent, comes from burning fossil fuels - roughly one-third from fuel used by industry; a little less than one-third from fuel consumed in transportation; nearly 20 percent from the fuel American use to heat, cool and operate their homes; and the remaining 15 percent from fuel used by commercial enterprises. 38 Since more than 30 percent of CO2 emissions come from transportation, and public transit accounts for only about one percent of vehicular transportation, its benefits as measured by CO2 reductions may appear modest. Nevertheless, as Table 22 shows, public transportation measurably reduces CO2 pollution, as a proportion of all the CO2 produced by driving, as well as VOCs, CO and NOx. Table 22. Environmental Benefits of Public Transportation As a Share of All Pollution Produced by Driving, 1999, Metric Tons
Virtually all public transportation systems in the United States are located in major metropolitan areas, and this concentration in dense urban and near-suburban areas increases public transportation's potential for providing greater environmental benefits. In most urban areas, almost all sources of pollution other than transportation are already tightly regulated. The only significant approach that remains for achieving major reductions in pollution is to focus more on emissions produced by driving, and therefore increasing the use of public transportation is the only strategy currently available that could achieve this without more regulation. The greatest environmental and economic benefits would be derived from greater use of public transportation, especially rail, in those areas where the air quality is poorest and the population density is greatest. 39 Almost half of the 35 largest public transportation systems, serving 26 metropolitan areas, are located in areas that currently fail to meet EPA air-quality standards for ozone (produced when VOCs and NOx combine with sunlight) or CO. 40 The nation's two largest metropolitan areas, New York and Los Angeles, fail to meet these standards in both ozone and CO. For all the highly-populated, urban and suburban "non-attainment areas," the major reductions in pollution that public transportation can deliver, compared to private vehicles, would directly go to the environmental bottom line. There is no simple formula to determine the energy savings and environmental benefits from the use of public transportation in a particular local or metropolitan area. Local authorities can estimate the savings and benefits of their own public transportation systems by adapting the approach of this study to their own communities.
Public transportation would produce much greater environmental benefits, if more Americans left their cars at home and used the transit systems already in place. Canadians use public transportation at seven times the American rate, and Europeans use buses and trains ten times as much as Americans. (41) If we matched Canadians in the use of public transportation, it would reduce potential CO pollution by nearly twice the combined levels emitted by four high-polluting industry groups (chemical manufacturing, oil and gas production, metals processing, and industrial uses of coal). It also would cut potential NOx pollution by one-fourth of the combined NOx emissions from the four industries, and the reductions in VOC pollution would be equivalent to almost 60 percent of the combined VOC emissions of the four industries. Similarly, if Americans used public transportation at the same rate as Europeans, it would reduce CO emissions by almost three times the combined CO output of the four industries identified above, and cut NOx emissions by more than one-third of the combined NOx pollution from these four industries. The reductions in VOC pollution would be equal to more than 84 percent of the total VOC emissions from these industries. Turning to global warming, the use of public transportation reduces potential CO2 emissions by 7,405,856 metric tons. If we used public transit at the rate Canadians do, we would save more than 50 million metric tons of CO2; and if we matched the Europeans, we could cut CO2 emissions by about 74 million metric tons. At the Canadian rate, the benefits for global warming in the United States would equal nearly 20 percent of all CO2 emitted from fuel burned for residential uses and more than 20 percent of the CO2 emitted by commercial enterprises. If we used public transit as often as Europeans do, the gains for climate change would equal nearly one-fourth of the reductions mandated by the Kyoto agreement. 42 Table 23. Emissions of Carbon Dioxide (CO2): Benefits of Public Transportation as a Share of Emissions By Sector, 1999 43
Greater reliance on more fuel-efficient means of travel, especially use of public transportation is the key to the United States achieving greater energy independence and environmental progress. The facts are clear and indisputable. For every passenger mile traveled by Americans, public transportation consumes about one-half the fuel and energy of private automobiles, SUVs and light trucks. For every passenger mile traveled by Americans, public transportation produces only five percent as much carbon monoxide, less than ten percent as much volatile organic compounds, and little more than half as much carbon dioxide and nitrogen oxides. Greater use of public transportation offers the most effective strategy available for achieving significant energy savings and environmental gains without imposing new taxes, government mandates or regulations. At our current levels of use, every year public transportation saves close to one billion gallons of gasoline and reduces harmful emissions by millions of tons. Increasing Americans' use of public transit would produce even greater benefits for our nation's economy, security and environment. This is an achievable goal - and one that Americans had formerly attained. In the early 20 th century, America led the world in mass transit development and use. Today, there are signs of a transit renaissance. Since 1995, use of public transportation has grown faster than the use of private vehicles. Passenger miles ridden on public buses and rail systems have grown faster than the passenger miles ridden in private automobiles, sports utility vehicles (SUVs) and light trucks. As ridership increases, so will the energy savings and environmental benefits. Both pragmatism and patriotism can become catalysts for much greater use of public transportation. As a practical matter, increasing transit use may be one of the most feasible -- and desirable -- strategies for sharply reducing our dependence on foreign oil and making historic strides in environmental quality. As a act of civic commitment, many Americans may view riding public transportation, even on a limited basis, as a small but important contribution to our country's well being. As this study demonstrates, if one out of ten people shifted his or her daily transportation from private vehicle to transit, or if the general public used transit for only 10 percent of its daily transportation needs or used public transportation for three days every month, the energy savings and environmental benefits would be enormous: the United States would no longer need to import oil from Saudi Arabia, every metropolitan area in the country would meet EPA air quality standards for smog and carbon monoxide, and America would achieve more than one-fourth of the reductions in global-warming emissions directed under the Kyoto Agreement. Realizing these benefits does not depend on technology or new regulatory schemes, but rather on a political and economic commitment. By making public transit a key element of our nation's long-term transportation, energy and environmental policies, we can attain conservation and clear air goals that strengthen America. * * * The technical approach employed in this study to estimate the energy and environmental effects of public transportation is designed to be conceptually transparent and rely on readily available data. This ensures that the results can be easily understood and verified. In essence, we postulate a world without public transportation and estimate how much additional fuel consumption and pollutant emissions would occur if current users of public transit had to rely instead on private automobiles. To do this, we first estimated the energy used and the pollution caused by public transportation. Buses account for roughly half of the more than 42.5 billion passenger miles that public transit systems provided in 1998; commuter rail, light rail, and heavy rail systems account for almost all of the other half of public-transit passenger miles. Public buses use primarily diesel fuel, with relatively modest amounts of other fossil fuels, while electricity powers most of the rail systems. The amount of fuels used in public transportation is determined by calculating the distance traveled by each mode of public transit and the fuel consumed by each mode to traverse those miles. The aggregate fuel consumption of each of the modes of public transit is converted to British thermal units (Btus) to arrive at the total energy consumed by public transportation systems. Both public transit and private automobiles emit four major classes of pollutants into the environment: volatile organic compounds, nitrogen oxides, carbon monoxide, and carbon dioxide. For diesel-powered buses and commuter-rail locomotives, emissions are determined on a grams-per-vehicle-mile-traveled basis, which then is multiplied by the total miles traveled by these modes of public transit to calculate the total pollution produced by them. The emissions associated with electrically-powered light-rail and heavy-rail systems are calculated by determining the total emissions produced by utilities, in grams per million kilowatt hours (MKWH), which is then multiplied by the electric power in MKWH used by public transportation systems. Once we calculate the energy needs and environmental costs associated with public transportation, we perform a thought experiment in which public transportation is no longer available and the passenger miles currently traveled on public transit occur instead in private automobiles, SUVs and light trucks. We do not assume that in a world without public transportation, all those currently using it would become lone drivers of private vehicles. Commuting to work or to school accounts for a majority of current passenger miles on public transportation, and a significant share of these trips involves at least two people in one vehicle (a driver and passenger). To accurately distribute the passenger miles from public transportation to private automobiles, we use the four-category distribution for private automobile travel from the 1995 Nationwide Personal Transportation Survey -- single driver with no passengers; driver plus one passenger; driver plus two passengers; and driver plus three or more passengers. Based on this distribution, we calculated the total number of automobile vehicle miles required to replace all the public transportation passenger miles. We multiply those vehicle miles by the average fuel consumption and pollution emissions, per mile, for passenger cars, SUVs, and light-duty trucks, in the appropriate proportions, to determine the fuel consumed and pollution emitted if current public transportation needs had to be met by private automobiles. The difference between the fuel consumption and pollution levels associated with the current use of public transportation, and the higher levels of energy consumed and pollution emitted by the automobile trips required to replace public transit, provides an accurate measure of the net energy and environmental benefits of public transportation. These differences are expressed in a variety of ways to illustrate the dimensions of the current energy and environmental benefits of public transportation. * * * TABLES Table 1. Primary Energy Consumption by Sector and Source, 2000 Table 2. Public Transportation Use and Implicit Energy Savings, 1998 and 1999 Table 3. Emissions by Public Transit and by Comparable Use of Private Vehicles Metric Tons, 1999 Table 4. Passenger Miles and Shares by Mode of Transportation, 1998 Table 5. Changes in Passenger Miles, 1980-1990, 1990-1995, and 1995-1998 Table 6. Energy Consumption, Private and Public Transportation, Btus, 1998 Table 7. Fuel Consumption by Mode of Public Transport, 1998 Table 8. Vehicle Miles and Passenger Miles, By Mode of Public Transport, 1998 Table 9. Average Passenger Load for Public and Private Vehicle Transportation, 1998 Table 10. Energy Efficiency of Public Transportation, by Fuel Source Per Mile and Per Passenger Mile, 1998 Table 11. Private Vehicle Miles Driven in Shift from Public to Private Transportation Table 12. Vehicles Miles and Fuel Efficiency of Private Vehicles, 1998 Table 13. Values for Determining the Energy Benefits of Public Transportation, 1998 Table 15. Public Transportation Vehicle Miles by Mode, 1999 Table 16a. Emissions by Buses and Diesel-Powered Trains, Grams/Vehicle Mile, 1999 Table 16b. Emissions by Electricity-Powered Rail Systems, Grams/MKWH, 1999 Table 17. Pollution Emissions by Public Transportation, by Mode, Metric Tons, 1999 Table 18. Pollution Emissions by Private Vehicles, Grams Per Vehicle Mile, 1999 Table 19. Private Vehicle Miles Driven in Shift from Public Transportation, 1999
1 Energy Information Administration, Department of Energy, Annual Energy Review, Table 2.1a, "Energy Consumption by Sector, 1949-2000," www.eia.doe.gov/emeu/aer/txt/tab0201a.htm. National Transportation Statistics, 2000, Bureau of Transportation Statistics, U. S. Department of Transportation, April 2001, Table 4-2, p. 232. 2 As noted earlier, the analysis of public transportation includes all bus, commuter rail and light and heavy rail trips within a metropolitan area; it does not include taxicabs, ferry boats or trolley buses, nor inter-city train, bus or air service. The analysis of private vehicle travel includes automobiles, sports utility vehicles and light trucks; it does not include motorcycles or trucks with six or more tires. 3 Energy Information Administration, U. S. Department of Energy, www.eia.doe.gov/emeu/aer/txt/tab0205.html, also, Monthly Energy Review, www.eia.doe.gov/mer/. 4 Sulfur dioxide (SO2) is also emitted in substantial quantities by electric utilities and in very small amounts by automobiles. This pollutant is not included in the analysis because its nationwide emissions are capped at a given level, and the fixed amount allowed is distributed based on an emission allowance trading system. Thus, total SO2 emissions (due to the use of electricity by rail systems) will not change whether public transportation exists or not. In light of this, omitting the small SO2 emissions from automobiles means that the environmental benefits of public transportation are understated in this analysis. 5 U. S. Environmental Protection Agency, Office of Air and Radiation, "Regulatory Impact Analysis - Control of Air Pollution from Motor Vehicles: Tier 2 Motor Vehicle Emission Standards and Gasoline Sulfur Control Requirements," December 1999, Table IV-9. 6 Environmental Protection Agency, National Emissions (1970 to 1998) by Tier 3 Source Category and Pollutant, Appendix A, Table A. 1 www.epa.gov/ttn/chief/trends98/appendix_a.pdf. See Table 20a below. 7 Ibid, Tables A. 2 and A. 3. See Tables 20b and 20c below 8 "Milestones in Public Transportation History," American Public Transportation Association, www.apta.com/stats/history/mileston.htm 9 Public Transit in America: Findings from the 1995 Nationwide Personal Transportation Survey, Center for Urban Transportation Research, University of South Florida, September 1998. 10 National Transportation Statistics, 2000, Bureau of Transportation Statistics, U. S. Department of Transportation, April 2001, Table 1-31, p. 48. Public Transportation Fact Book, American Public Transportation Association, March 2001, Table 30, p. 70. 11 National Transportation Statistics, 2000, Bureau of Transportation Statistics, U. S. Department of Transportation, April 2001, Table 1-31, p. 48. 12 American Public Transportation Association, Public Transportation Fact Book, 2001, Table 26, p. 66. 13 National Transportation, Statistics, ibid., Table 1-35, p. 56. 14 Making Transit Work: Insight from Western Europe, Canada and the United States, Transportation Research Board, Committee for an International Comparison of National Policies and Expectations Affecting Public Transit, National Research Council, Special Report 257, Washington DC: 2001, p. 1 15 Energy Information Administration, U. S. Department of Energy, www.eia.doe.gov/emeu/aer/txt/tab0201a.html. 16 Environmental Protection Agency, Appendix A, National Emissions (1970 to 1998) by Tier 3 Source Category and Pollutant, Table A. 1, www.epa.gov/ttn/chief/trends98/appendix_a.pdf. See Table 21b below. 17 Ibid., Tables A. 2 and A. 3. See Tables 21a and 21c below. 18 Making Transit Work: Insight from Western Europe, Canada and the United States, op. cit., pp. 1-2.
20 National Transportation Statistics, op. cit., Table 4-5, p. 238. 22 Public Transportation Fact Book, 2001, American Public Transportation Association, Table 65, "Fossil Fuel Consumption by Mode," p. 112; Table 66, "Non-Diesel Fossil Fuel Consumption by Mode," p. 113 distributing the bus total using Table 50, "Passenger Vehicle Power Sources", p. 90, and Table 51, "Bus Power Sources", p. 91; Table 67, "Electric Power Consumption by Mode, Table 67, p. 114. 23 Ibid, Table 42, "Vehicle Miles Operated by Mode," p. 78; and Table 51, "Bus Power Sources," p. 91. 24 Ibid, Table 30, "Passenger Miles by Mode," p. 70; and Table 51, "Bus Power Sources," p. 91. 25 Public Transportation Fact Book, 2001, American Public Transportation Association, Table 30, "Passenger Miles by Mode", p. 70; Table 42, "Vehicle Miles by Mode", p. 78; distributing the commuter rail vehicle and passenger miles according to Table 50, "Passenger Vehicle Power Sources", p. 90 -80% are assumed to be electrically-powered and the remaining 20% diesel powered. Bus vehicle and passenger miles were distributed using Table 50 and Table 51, "Bus Power Sources", p. 91. Note that this method of distributing the total bus vehicle and passenger miles assumes that the same number of miles are driven per bus fuel type. This is probably not precisely the case, but the data are not sufficiently disaggregated to make the appropriate adjustments. The error introduced due to this simplification is minor because diesel-powered buses constitute the vast majority of this mode of public transportation. 26 National Transportation Statistics, 2000, op. cit., Tables 1-29 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
