Energy Conservation and Travel Behavior

Jeffrey S. Milstein, Ph.D., Department of Energy
ABSTRACT - Americans use one quarter of all energy consumed in the United States in automobile passenger travel. This paper describes the ways Americans could reduce this energy consumption, and, using empirical data, describes the extent to which these energy-conserving behaviors are or are not being practiced. [The findings and interpretations in this paper should not be interpreted as necessarily representing the official policies, either expressed or implied, of the Department of Energy or of the U.S. Government.]
[ to cite ]:
Jeffrey S. Milstein (1978) ,"Energy Conservation and Travel Behavior", in NA - Advances in Consumer Research Volume 05, eds. Kent Hunt, Ann Abor, MI : Association for Consumer Research, Pages: 422-425.

Advances in Consumer Research Volume 5, 1978      Pages 422-425

ENERGY CONSERVATION AND TRAVEL BEHAVIOR

Jeffrey S. Milstein, Ph.D., Department of Energy

ABSTRACT -

Americans use one quarter of all energy consumed in the United States in automobile passenger travel. This paper describes the ways Americans could reduce this energy consumption, and, using empirical data, describes the extent to which these energy-conserving behaviors are or are not being practiced. [The findings and interpretations in this paper should not be interpreted as necessarily representing the official policies, either expressed or implied, of the Department of Energy or of the U.S. Government.]

THE ENERGY PROBLEM

Today, with only 5 percent of the world's population, Americans are consuming 30 percent of the world's petroleum production. [Federal Energy News, FEA, Aug. 29, 1977.] This consumption of oil comes at an increasingly high cost, for this Nation must import an increasingly larger share of its oil. Imports for the first half of this year amount to 47 percent of total consumption, compared to 39 percent for the first half of 1976. The cost of this imported oil is growing at a staggering rate: this year alone U.S. citizens will pay foreign oil producers $45 billion for the oil we are importing! This is up from $37 billion in 1976, $27 billion in 1975, $8 billion in 1973, and only $4 billion in 1971. Moreover, 41 percent of these imports come from countries that have shut off the flow of oil to us in the past, and could again. [Federal Energy News, FEA, Aug. 29, 1977.] The potentially enormous negative consequences for our economy if oil is again shut off, as well as the consequences for our national security and independence of our foreign policies, are urgent national and international reasons for the citizens of our Nation to consume less energy.

TRAVEL BY CAR: A GREAT USER OF ENERGY

What has this to do with travel behavior? Passenger travel is an enormous user of our energy, particularly of petroleum. Sixteen percent of all our energy is used directly in passenger travel. Nine-tenths of all passenger travel is in automobiles. Travel by car uses 57 percent of all energy used in transportation in the United States. (Air passenger travel is a distant second, using 6 percent of U.S. transportation energy.)

About 2 out of every 5 BTU's of energy used in automobile passenger travel is used indirectly. Thus, to the 14 percent of all our energy directly consumed by automobiles as gasoline and oil, one must add such energy use for automobile travel as manufacture of motor vehicles, parts, tires, and repairs (about 4 percent more of our total energy use); highway construction (about 2 percent); and petroleum refining and distribution losses (about 5 percent). Thus, directly and indirectly, automobile passenger travel uses one-fourth of all our Nation's energy and ["National Transportation: Trends and Choices," U.S. Department of Transportation, January, 1977, p. 33.] an even greater percentage of our oilBabout30 percent. American cars are now using about 1 out of every 10 barrels of oil produced in the world! As a major consumer of energy then, automobile travel by Americans is a major focus for energy conservation measures.

The Department of Energy and its predecessor organizations have recommended for almost 4 years various ways that private citizens and consumers can reduce their energy use. In the area of transportation behavior, I will go through those major recommendations and then describe (using empirical data) the extent to which the American public is or is not practicing these ways to conserve energy.

BUYING EFFICIENT CARS

The first travel-related behavior that saves energy is for people to buy efficient cars that suit their needs. In 1977, the average miles per gallon of new cars sold, including imports, was 18.6 miles per gallon. That was up from 17.6 in 1976, 15.6 in 1975, and 13.9 in 1974. [Data are from the Motor Vehicle Manufacturer's Association.] Thus, from 1974 to 1977, there has been a 34 percent increase in new car fuel efficiency. This has come about as car manufacturers have been required by law to increase the average efficiency of new cars.

Related to the operating fuel efficiency of new cars is their size. Smaller cars also use less indirect energy, such as that necessary to produce additional amounts of steel for larger cars. The market shares for different sizes of cars, including imports, in 1977 and 1976 are as follows: [These data are from January 1 to August 20, for the respective years. The data comes from Wards Communications, Inc.]

                                1977         1976

Subcompacts             25%         23%

Compacts                  22%         25%

Intermediates             28%          28%

Full-size                     24%          23%

Vans                          1%             1%

Note that part of the increase in subcompact sales from 1976 to 1977 includes an increase in foreign car sales from 14 percent of the total market in 1976 to 19 percent in 1977. Nine out of ten foreign cars are subcompact in size. Thus, part of the gain in the new car fleet's fuel efficiency is due to the increased sales of foreign cars. While importing cars hurts our balance of payments, it does not also make the United States strategically vulnerable as does the importing of oil.

RIDESHARING

Ridesharing, especially to and from work, but also including shopping with a neighbor, is one of the best ways that American consumers could cut down on their vehicle miles traveled and therefore save energy. A three-person carpool uses just one-third of the energy that the three people driving alone would use. About one-third of all private automobile mileage is for commuters to and from work. If the average occupancy (currently 1.3 people per commuter car) were increased by just one person, not only would each commuter reduce his cost, energy use, and driving stress, but the Nation would save more than 700,000 barrels of gasoline per day. ["Tips for Energy Savers," Federal Energy Administration, 1977.] This is approximately one barrel out of every ten for gasoline that Americans use. If just one gallon of gasoline were saved each week for each automobile in the country, we would save about 5.2 billion gallons of gasoline in a year or about 7 percent of all the demand created by all of our passenger cars.

The empirical data shows that half of all trips have only one occupant per car. Of trips to and from work, approximately three out of four were in one-occupant cars. ["Nationwide Personal Transportation Study, Automobile Occupancy" Report No. 1, April 1972, DOT/Federal Highway Administration.] A 1973-74 national survey of work trips shows that approximately one out of four persons is going to and from work in a vehicle with two or more people. ["Nationwide Personal Transportation Study: Home to Work Trips and Travel," Report No. 8, August 1973, DOT/ Federal Highway Administration.] [Note that the distribution of vehicles is somewhat different from the distribution of persons because of multiple occupancy in carpools.]

Though these data come from studies by the Department of Transportation in 1972 and 1973, more recent FEA surveys I have directed show that carpooling has not significantly increased since the oil embargo of 1973-74.

Carpooling varies tremendously around the country: as many as half the people in Washington, D.C., and in Minneapolis-St. Paul carpool to work. Moreover, where special carpool facilities exist, such as the Shirley Highway bus and carpool express lanes into Washington, D.C., from Northern Virginia, we find as many as three out of five people in these corridors taking cars are in carpools. But on a national basis, the great energy savings potential of carpooling and vanpooling is far from being realized.

PUBLIC TRANSIT

Public transit uses just one-sixth to one-third the energy per passenger mile that single occupancy cars do ["Buses Hailed, Rail Transit Scored in Energy-Use Study by Congress," New York Times, Sept. 23, 1977, p. 18.]. However, various studies show that only 6 to 8 percent of the public takes public transportation to and from work. ["Nationwide Personal Transportation Study: Home to Work Trips and Travel," Report No. 8, August 1973, U.S. DOT/Federal Highway Administration; also, FEA Survey by Opinion Research Corporation, 1975, Vols. 11 & 12.]

In the FEA surveys that I have directed, an analysis of why people do or do not use public transit for going to and from work shows that 17 percent of the total public say that mass transit does not run at the right times, 11 percent say it does not go where they need to go, 9 percent say it does not run often enough, 8 percent say it takes longer, 5 percent say that they do not because public transit encounters delays and holdups, 4 percent cite overcrowding on public transit, and 1 percent cite dirty vehicles as the drawback from their point of view. ["The Public's Attitudes Toward and Knowledge of Energy Related Issues," Highlight Report Vol. XI, FEA, June, 1975.]

In a multivariate analysis of the FEA survey data, we found that half of the users of public transit encountered heavy traffic and jammed highways on the way to and from work, whereas only 27 percent of the drivers of their own car did so, and 38 percent of car-poolers did so. We infer from this that traffic jams or heavy traffic are important inducements for people to take public transit. An analysis of the 30 percent of our total population who have a choice between taking cars or public transit to and from work (i.e. have public transit available to them) shows that the factors people seem to consider in taking public transit are: the distance and duration of travel, the convenience and timing of the schedules, the proximity of the transit line to where they work and live, the cost of the travel, and whether or not they encounter heavy traffic or traffic jams on the way to and from work. ["General Public Behavior and Attitudes," Highlight Report Vol. XII, FEA, July, 1975.]

Analysis of the FEA survey data also show that a large fraction of the people who take public transit are also people who would carpool and vice versa. These people are different in their attitudes and behavior from people who drive alone to and from work. An important implication from this finding is that promoting public transit ridership might be at the expense of some car-pooling, and the promotion of carpooling might be at some expense to public transit ridership. Again, the enormous potential for energy savings in public transit riding is not being realized.

WALKING

Five percent of the public walks to and from work. The percentage who use this energy saving mode of transportation appears small, but is nearly as large as the percentage who take public transportation to and from work. ["Consumer Attitudes, Knowledge and Behavior Regarding Energy Conservation," FEA, December, 1976.]

VACATION TRAVEL

In a recent survey, it was found that six out of ten households in the United States took one or more vacation trips in 1976, and half of all households took a vacation trip by car. The average number of trips taken by vacationing households was more than two trips per year. Half of the households who take vacation trips take two or more vacation trips per year. On vacation trips, the average travel party consists of three people (typically a family). The average mileage driven per year is about 3,500 for all household vacations. (This is about a quarter of all miles driven per year.) The median income of families taking automobile vacation trips in 1976 is about a quarter higher than the median income for all families in the United States (i.e., $17,640 versus $14,000 per year). ["The 1977 Automobile Travel Intention Survey" December 2, 1976, unpublished paper by James J. Gibson, 3M National Advertising Company.]

Vacation travel took a temporary dip during the Spring of 1974 during the oil embargo, and during the 1975 recession. Vacation travel increased, however, in 1976 and again in 1977. Thus, energy-conserving travel behavior such as vacationing near home, staying in one place instead of traveling around, and taking a train or bus instead of the family car, have not been significantly practiced since the oil embargo and subsequent recession. Americans continue to use a large amount of energy on their vacation travelBan integral part of the lifestyles of a majority of Americans.

DRIVING SLOWER: THE 55 MILE PER HOUR SPEED LIMIT

Most automobiles get about 20 percent more miles per gallon on the highway at 55 miles per hour than they do at 70 miles per hour. Fatal automobile accidents are also less likely at the slower speeds. Thus there are both energy and safety reasons to drive slower on the highway.

In 1973, the mean speed on the highways which had free flow conditions (i.e., the 45 percent of American roads which have only the 55 mile per hour speed limit as a control) was 60 miles per hour with a standard deviation of 10. In 1974, the mean speed dropped to 55 miles per hour with a standard deviation of 6. ["Transportation Safety Information Report," Assistant Secretary for Environment, Safety and Consumer Affairs, U.S. DOT, 1977.]

In 1977, the majority of States have average speeds between 55 and 60 miles per hour. This shift in the mean speed that occurred between 1973 and 1974 (when the 55 mile per hour speed limit became law in every State) has continued since 1974. The proportionate gasoline savings have also continued as a result of people driving at this more efficient speed on the open highway. [U.S. DOT/Federal Highway Administration, Highway Statistics Division, "Quarterly Speed Summary," June 1977.]

OTHER EFFICIENT DRIVING BEHAVIORS

There are other driving techniques that a careful driver can use to get 20 percent more miles per gallon than the average driver and 50 percent more than a wasteful one. These techniques include accelerating smoothly and moderately, driving at a steady pace, avoiding stop and go traffic, minimizing braking, not letting the motor idle for more than a minute, not overfilling the gasoline tank, planning trips carefully, having the car tuned (3-9 percent savings), keeping the engine air filter clean, checking tire pressure regularly (2 percent savings per pound of underinflation), using radial tires (3-10 percent savings) and removing unnecessary weight from the car. ["Tips for Energy Savers," FEA, 1977.]

Reliable and valid data on these kinds of behavior on the part of drivers is not readily available. But it is a part of travel behavior where energy savings can add up to significant amounts.

THE BOTTOM LINE: GASOLINE CONSUMPTION

Distilling all automobile travel behavior down to the bottom line of gasoline consumption, we find that motor gasoline demand for January through August of 1977 averaged 7.1 million barrels per day, or 81 percent of our imports. That is nearly 300 million gallons of gasoline per day. While that averages only 2 2/3's gallons per automobile per day (or an average of about 40 miles driven per day), it is an amount that is 2.1 percent higher than the average for 1976. ["Monthly Energy Review," FEA, August, 1977.]

Since 1972, gasoline consumption has been increasing at an average annual rate of 2.6 percent per year. However, new car registrations have been increasing an average of 3.3 percent per year from 1972 to 1976, ["Total Automobile Registrations," U.S. DOT, 1977.] which is slightly faster than gasoline consumption. Thus, even though in the aggregate, Americans are using more gasoline in cars, on a per capita basis, there has been a slight amount of energy conservation in gasoline used by the American people. (One explanation for this is that in the growing number of two-car families, the second car is not driven as much on long family vacation trips.)

CONCLUSION

In summary, Americans appear to be making some progress in conserving energy in such areas as buying more efficient cars and driving slower on the highways, but little or no progress in such other important areas as carpooling, using public transit, and reducing vacation travel. The challenge that lies before us still is to reduce by significant, rather than trivial amounts, the fuel consumption of Americans as they travel. We must use all of the means possible to save energy. We cannot forget or ignore the enormous international and domestic economic and political stakes that are present in this challenge.

REFERENCES

Federal Energy Administration. "Consumer Attitudes, Knowledge and Behavior Regarding Energy Conservation." Prepared for FEA by Opinion Research Corporation, Princeton, New Jersey. (National Technical Information Service: Springfield, Virginia, December 1976). (FEA/D-76/469)

Federal Energy Administration. Federal Energy News. (Washington, D.C., August 29, 1977).

Federal Energy Administration. "General Public Behavior and Attitudes Regarding Vacation and Business Travel, Beverage Containers, Reasons for Using Mass Transit." Highlight Report, vol. 12. Prepared for FEA by Opinion Research Corporation, Princeton, New Jersey. (National Technical Information Service: Springfield, Virginia, July 1975). (PB 244 969/AS)

Federal Energy Administration. "Monthly Energy Review." (Washington, D.C., August 1977).

Federal Energy Administration. "The Public's Attitudes Toward and Knowledge of Energy-Related Issues." Highlight Report, vol. 11. Prepared for FEA by Opinion Research Corporation, Princeton, New Jersey. (National Technical Information Service: Springfield, Virginia, June 1975). (PB 244 987/AS)

Federal Energy Administration. "Tips for Energy Savers." (Washington, D.C., 1977).

James J. Gibson. "The 1977 Automobile Travel Intention Survey." 3M National Advertising Company. (unpublished report, December 2, 1976).

Holsendolph, Ernest. "Buses Hailed, Rail Transit Scored in Energy-Use Study by Congress." (The New York Times, September 23, 1977). p. 18.

Department of Transportation. "National Transportation: Trends and Choices." (U.S. DOT, Washington, D.C., January 1977). p.33.

Department of Transportation. "Nationwide Personal Transportation Study Automobile Occupancy." Report No. 1. (DOT/Federal Highway Administration, Washington, D.C., April 1972).

Department of Transportation. "Nationwide Personal Transportation Study: Home to Work Trips and Travel." Report No. 8. (U.S. DOT, Washington, D.C., August 1973).

Department of Transportation. Assistant Secretary for Environment, Safety and Consumer Affairs. "Transportation Safety Information Report." (U.S. DOT, Washington, D.C., 1977).

Department of Transportation. "Total Automobile Registrations.'' (U.S. DOT, Washington, D.C., 1977).

Department of Transportation, Federal Highway Administration, Highway Statistics Division, "Quarterly Speed Sun, nary." (U.S. DOT, June 1977).

----------------------------------------