NHTS

Highlights of the 2001 

National Household Travel Survey

U.S. Department of 

Transportation

Bureau of Transportation 

Statistics
 
NHTS

Highlights of the 2001 

National Household Travel Survey

BUREAU OF TRANSPORTATION STATISTICS U.S. DEPARTMENT OF TRANSPORTATION
Bureau of Transportation Statistics

Our mission: To lead in developing transportation data and information of high 

quality and to advance their effective use in both public and private transportation 

decisionmaking.

Our vision for the future: Data and information of high quality supporting every 

significant transportation policy decision, thus advancing the quality of life and the 

economic well-being of all Americans.

To obtain NHTS 2001 Highlights Report

and other BTS publications 

Mail: Product Orders

Bureau of Transportation Statistics

U.S. Department of Transportation

400 Seventh Street, SW, K-15

Washington, DC 20590 

Phone: 202-366-DATA [press 1]

Fax: 202-366-3197

Internet: www.bts.gov

BTS Information Service

Email: answers@bts.gov

1-800-853-1351

Recommended citation

U.S. Department of Transportation, Bureau of Transportation Statistics,

NHTS 2001 Highlights Report, BTS03-05

(Washington, DC: 2003).

All material contained in this report is in the public domain and 

may be used and reprinted without special permission; source 

citation is required.
U.S. Department of

Transportation

Norman Y. Mineta

Secretary

Michael P. Jackson

Deputy Secretary

Bureau of 

Transportation

Statistics

Rick Kowalewski

Deputy Director

John V. Wells

Chief Economist

William Chang

Associate Director for

Information Systems

Jeremy Wu

Acting Chief Statistician

Acknowledgments

Produced under the direction of:

Michael Cohen

Assistant Director for Survey Programs

Major Contributors

Jonaki Bose

Lee Giesbrecht

Joy Sharp

Other Contributors

Bill Bannister

Kay Drucker

Wendell Fletcher

Bruce Goldberg

Brent Gray

Xiaoli Han

Ivy Harrison

Michele Janis

June Jones

Ed Kashuba (FHWA)

Editor

Chip Moore

Report Layout and Production

Lorisa Smith

Rick Kowalewski

Susan Liss (FHWA)

Jeff Memmott

Nancy McGuckin (FHWA)

Adam Pollock

Pheny Smith

Deepak Virmani

John Wells

Jeremy Wu
 
v

Table of Contents

Executive Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Passenger travel in the United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Data source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Report approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Household, Individual, and Vehicle Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . 6

Daily Passenger Travel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Who is traveling?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

How do they travel? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Why do they travel? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

When do they travel? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

How many people are traveling? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Experiences behind the wheel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Long-Distance Travel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Who is traveling?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

How are they traveling on long-distance trips? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Why are Americans traveling long distances? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Where are Americans traveling? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Methodological Considerations, Data Reliability, and Data Comparability. . . . . . 15

Survey methodology. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Sample design. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Data reliability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Data comparability: changes from prior surveys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Appendix A—Tables with Estimates Used in the Report and Standard Errors . . . 19

Appendix B—Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Appendix C—Census Regions and Divisions of the United States . . . . . . . . . . . . 31

1

Executive Summary

BACKGROUND

The 2001 National Household Travel Survey

(NHTS) is the first comprehensive household

survey of both daily and long-distance travel,

allowing for analysis of the full continuum of personal travel by Americans. This report highlights

the breadth of topics covered by the survey, the different kinds of analyses possible using the data

gathered, and the unique features of these data.

In addition to providing the first comprehensive

look at travel by Americans, the 2001 NHTS also

incorporates additional enhancements to the previous survey designs (see box A). For example,

long-distance travel was expanded to include trips

as short as 50 miles and, for the first time, includes

trips made for the purpose of commuting to

work—often overlooked segments of personal

long-distance travel. The survey also introduces

the first look at the daily travel characteristics of

children under the age of five years.

Furthermore, specific questions and probes

were added to capture biking and walking

trips—trips thought to be underrepresented in

prior surveys. As a result of the changes to trip

definitions, population coverage, and survey

methodology, a limited amount of direct comparisons can be made between data from the 1995

surveys and the data from the 2001 NHTS, as

presented in this report.

Within the 2001 NHTS, daily and longdistance travel do not have the same definition.

While each includes travel by all modes and for

all purposes, trips captured in daily travel are

reported for one specific day referred to as the

“travel day.” Travel made from one address to

another is reported as a separate trip; therefore,

a trip does not have to originate from home and,

in fact, home-to-home journeys made during the

day are reported as multiple trips with varying

originating locations. Conversely, long-distance

trips are defined as trips of at least 50 miles to

the furthest destination—originating from

home—and include the return component of the

trip as well as any overnight stops and stops

made to change transportation modes. Longdistance trips were collected during a specific

4-week period, known as the “travel period.” It

is also important to note that trips of 50 miles or

more away from home made during the travel

day are potentially included both in daily and

long-distance travel; however, the way in which

Box A 

About the 2001 NHTS

This survey updates information gathered by two prior 

survey series—the Nationwide Personal Transportation Survey (NPTS) conducted in 1969, 1977, 1983, 

1990, and 1995 and the American Travel Survey 

(ATS) conducted in 1977 and 1995. The final NPTS, 

sponsored by the Federal Highway Administration, 

primarily focused on daily travel, with an abbreviated 

long-distance component. The 1995 ATS, sponsored 

by the Bureau of Transportation Statistics, provided a 

detailed look at long-distance travel defined as trips of 

100 miles or more from home.

NOTE: Tables with an “A”prefix (Tables A1, A2, etc.) can

be found in Appendix A.
2

the trips are reported differs in definition, details

collected, and estimated distance traveled.

The objective of this report is to answer the

questions of who is traveling in the nation, and

how, why, when and where they are traveling—both

on a daily basis and on longer distance trips.

Consequently, this report is divided into three

main areas:

 travel-related characteristics of households and

individuals in the United States,

 characteristics of daily trips taken in the nation,

and

 characteristics of long-distance trips made

domestically (and to other countries).

RESULTS

The 2001 NHTS data demonstrate a widespread

prevalence of drivers and personal vehicles in the

nation. Nationwide, about 88 percent of persons 15

years or older are reported as drivers (table A-1).

While the mean number of vehicles owned or

available to U.S. households is 1.9 personal vehicles, on average those households have 1.8 drivers

(table A-2). Only 8 percent of households report

not having a vehicle available for regular use (table

A-4). Not surprisingly, the dominant mode of

transportation for both daily and long-distance

travel is by personal vehicle. The majority of daily

trips, 87 percent, were taken by personal vehicle

(table A-10). Similarly, 90 percent of long-distance

trips of 50 miles or more away from home were

made in personal vehicles (table 4 on p. 14).

Daily Travel

Results from the 2001 NHTS show that daily travel

in the United States totaled about 4 trillion miles

(table A-8), an average of 14,500 miles per person

annually. On a daily basis, Americans averaged 4

trips per day, totaling on average 40 miles of

travel—most of it (35 miles) in a personal vehicle.

While there were no significant differences

between men and women in the number of daily

trips taken,1

 there were differences based on age.

The total number of trips peaked among the

traditional working population ages 25 to 54 (4.6

daily trips) (table A-9). Children under the age of

five made the fewest daily trips, but still averaged

3.2 trips per day. Individuals 65 years or older

averaged 3.4 trips per day. 

While the majority of daily trips were taken in

personal vehicles, walking trips accounted for the

next highest percentage at almost 9 percent of all

trips (table A-10). Trips by transit and by school

bus each represented approximately 2 percent of

daily trips taken in 2001.

The largest portion of daily trips, 45 percent,

was made for family and personal reasons, such

as shopping and running errands (table A-11).

Another 27 percent were made for social and

recreational purposes, and 15 percent were made

for commuting to work.

Long-Distance Travel

In 2001, Americans took about 2.6 billion longdistance trips of 50 miles or more, totaling over 1.3

trillion personal miles of long-distance travel (table

A-22). The vast majority of these trips (98 percent)

were to destinations within the United States, with

62 percent of all long-distance trips to destinations

within the traveler’s home state (table 5 on p. 15).

The majority of long-distance travel was

made by men, accounting for 57 percent of all

long-distance trips (table 3 on p. 12). Over half,

or 57 percent, of all long-distance trips were

taken by persons living in households with total

household income of $50,000 or more (table A19). Nearly two-thirds of all long-distance trips

were made by persons aged 25 to 64 (table A-21).

Approximately 9 out of 10 long-distance trips

were taken by personal vehicle. Trips by airplane

accounted for the largest mode share of the

remaining trips, representing over 7 percent of all

long-distance trips in 2001. Travel by bus

accounted for 2 percent of these trips, and train

trips represented less than 1 percent of longdistance travel. Not surprisingly, the mode of

transportation was strongly influenced by the

distance of the trip. Personal vehicles were used

for over 97 percent of all trips of less than 300

roundtrip miles, while nearly three-quarters of

trips over 2,000 roundtrip miles were made by

airplane (table 4 on p. 14). 

1

 Although there are no significant differences between

men and women in number of daily trips taken, differences do exist in the length and duration of trip. 
3

Trips taken for pleasure purposes—vacations,

sightseeing trips, visiting friends and relatives,

outdoor recreation, etc.—represented over half

(56 percent) of all long-distance trips taken in

2001 (figure 12, p. 14, table A-24a). Meanwhile,

business trips to attend conferences or meetings

accounted for 16 percent of long-distance travel,

and commuting trips to work represented 13

percent of all long-distance travel. Trips made

for personal reasons or family business represented 13 percent of these trips.

The remainder of the report takes a detailed

look at traveler characteristics and the characteristics of long-distance and daily travel. 
 
5

Highlights from the 2001 National 

Household Travel Survey

INTRODUCTION

Passenger Travel in the United States

Almost every person in the United States is

affected in some way by the quality of our transportation infrastructure. A safe and efficient transportation system can further national interests,

support economic well-being, and enhance the

quality of life for persons in the country. To achieve

this, the Department of Transportation has identified five strategic objectives related to safety,

mobility, global connectivity, environmental stewardship, and security.2

 A few of these are dominant

themes in the arena of passenger travel. For example, the promotion of public health and safety by

working towards the elimination of transportation-related deaths and injuries directly impacts

the condition under which people can move

around their neighborhoods and across the country. Similarly, the shaping of an accessible, affordable, and reliable transportation system for all

people and regions affects the quality of life for all

people in the nation.

In order to attain the objectives outlined by the

Department and the needs of transportation

planners, better data are needed to understand

the current situation and measure changes over

time. One of the Department’s goals is to improve

mobility through outcomes such as decreased

congestion and improved accessibility of transportation. In part, the decisions on how to reduce

congestion cannot be made without data that

answer questions such as how, why, when,

where, for how long, and how far people travel,

and whether there are differences across sociodemographic or geography-based groups.

Similarly, in order to be inclusive, transportation

must be available to all people, including lowincome persons, the elderly, and persons with

disabilities. The process of improving the

transportation infrastructure related to passenger

travel requires an understanding of current passenger travel behavior patterns. Data on the travel

behavior of these populations help inform urban

planners and policymakers on how best to serve

the interests of such special-needs populations.

The 2001 National Household Travel Survey

(NHTS) is also intended to be used by researchers

and analysts in organizations, such as metropolitan planning organizations, universities, and state

and local governments, to understand how people make travel and residential decisions and to

predict the impact of those decisions on public

transportation from national and local perspectives. Greater understanding of travel patterns

allows communities to plan, invest in, and operate transportation systems that are better suited

to the public’s needs in areas such as travel

demand forecasting, multimode travel, transportation safety, and facility accessibility and use by

all segments of the population.

Data Source

This report presents selected highlights from the

2001 NHTS on daily and long-distance passenger

travel in the United States. The 2001 NHTS is

sponsored primarily by two agencies within the

U.S. Department of Transportation—the Bureau

of Transportation Statistics (BTS) and the Federal

Highway Administration (FHWA), with additional funding from the National Highway Traffic

Safety Administration (NHTSA). 

The survey included items on the numbers of

drivers and vehicles in the household, the characteristics of these vehicles, and the driver status of

all people residing in the household, along with

their views on transportation, use of public transit,

2 Draft DOT Strategic Plan for Fiscal Years 2003-2008, 1

July 2003.

NOTE: Tables with an “A”prefix (Tables A-1, A-2, etc.)

can be found in Appendix A.
6

walking, and biking activities in the last week. In

addition, for each individual, data were collected

on daily and long-distance trips taken during preassigned time frames. For daily trips, data were

collected on trip times; means of transportation;

which household vehicle was used, if any; wait

and access and egress (time from end of transit

trip to final destination) times for transit trips;

purpose; and presence of household and nonhousehold members. For long-distance trips of 50

miles or more one way, information was collected

on the number of trips made during a four-week

period, dates for the trips, whether the trip was

recurring, purpose and destination of trip, type of

lodging used at the destination, primary means of

transportation, overnight stops, and access and

egress information on airplane, bus, and train

trips. In addition, demographic information such

as age, sex, medical condition status, and country

of birth was collected on the people residing in

the household.

The 2001 NHTS updates information gathered

in the Nationwide Personal Transportation

Survey (NPTS) conducted in 1969, 1977, 1983,

1990, and 1995 and the American Travel Survey

(ATS), conducted in 1977 and 1995. The data are

results of telephone interviews with individuals

in sampled households. Data were collected from

about 26,000 nationally representative households and approximately 60,000 individuals,

which documented about a quarter-million daily

trips and 45,000 long-distance trips. Data were

collected from March 2001 to May 2002 by Westat,

which conducted the survey under contract for

the Department. (See section V for further details

on survey methodology.) The final public-use

data files and complete survey documentation

from the 2001 NHTS are scheduled for release in

the fall of 2003.

Households were asked about all trips (daily

travel) they took on a specific randomly assigned

day, labeled the “travel day,” and about trips of 50

miles or more taken from home in the 27 days

preceding and including the travel day (long-distance travel), a period labeled the “travel period.”

Report Approach

Because the purpose of this report is to introduce

readers to the contents and analytic potential of the

2001 NHTS survey and data, it does not provide

indepth analysis of the different facets of the data.

Instead it highlights the variety of topics covered

in the survey using basic charts and tables. The

report has three main content areas:

 travel-related characteristics of households and

individuals in the United States,

 characteristics of daily trips taken in the nation,

and

 characteristics of long-distance travel by people.

This report also includes a methodological section that provides details on data collection,

methodological constraints, and the computation

of standard errors for estimates in this report.

There is also a glossary of travel-related terms

used in this report. Appendix A provides tables

with estimates that were used in the text and figures, along with their associated standard errors.

HOUSEHOLD, INDIVIDUAL, AND VEHICLE 

CHARACTERISTICS

Nationwide, about 88 percent of persons 15 or

older are reported as drivers (table A-1). Interestingly, while the mean number of vehicles in

households is 1.9 personal vehicles, households in

the United States on average have 1.8 drivers who

are 15 years or older (table A-2). Thus, it appears

that households on average have more vehicles

than drivers. Not surprisingly, households with

more members are likely to have more personal

vehicles available for regular use. For example,

single-person households average about one vehicle while households with two members average

about two vehicles (figure 1, table A-3). However,

households with seven or more members average

about 2.8 personal vehicles. Not all households

have vehicles—8 percent of households in the

nation do not have a vehicle (figure 2, table A-4).

Households without a vehicle are not spread

uniformly across the population. For example,

households with an annual income of less than

$25,000 are almost nine times as likely to be a
7

zero-vehicle household than households with

incomes greater than $25,000. Though these measures are related, households living in a rented

residence are almost six times as likely to be a

zero-vehicle household compared to nonrenters.

Similarly, households living in a condominium or

apartment are almost five times as likely to be a

household with no vehicle compared to those

living in single family or other nonapartment

dwellings. Nineteen percent of the single-person

households have no vehicles compared to 4 percent of the multiperson households. Households

Figure 1

Mean Number of Vehicles by Household Size

7+ people

6 people

5 people

4 people

3 people

2 people

1 person

0 0.5 1 1.5 2 2.5 3

Number of vehicles

Figure 2

Percent of Households with Zero Vehicles

Household income less than $25,000

Household income of $25,000 or more

Residence is rented

Residence is owned/other

Residence is a condominium/apartment

Residence is not a condominium/apartment

Single-person household

Multiperson household

Household in rural area

Household in urban area

0 5 10 15 20 25

Percent of households

All households

SOURCE: The 2001 National Household Travel Survey, household 

file, U.S. Department of Transportation.

SOURCE: The 2001 National Household Travel Survey, household file, U.S. Department of Transportation.
8

in urban areas are also more than twice as likely to

be zero-vehicle households as those in rural areas

(figure 2, table A-4). 

The NHTS data demonstrate a widespread

prevalence of drivers and personal vehicle use in

the nation. There are about 204 million personal

vehicles available for regular use3

 in the United

States, and over half (57 percent) of these vehicles

are cars or station wagons (figure 3, table A-5).

About a fifth (21 percent) of these vehicles are

vans or sport utility vehicles (SUVs) and one-fifth

(18 percent) of these vehicles are pickup trucks.

Ninety-one percent of the adults commute to

work using personal vehicles (table 1). In comparison, only 5 percent of adults nationwide commute to work regularly using public transit.

Seventeen percent of adults report having used

public transit in the last two months (table A-1).

Despite the presence of almost one adult-size

bicycle per household (table A-2), on average only

about 8 percent of adults report taking a bicycle

trip in the last week (table A-1). 

The prevalence of personal vehicles makes it

important to understand the nature of personal

vehicle ownership as well. Not only is income

related to the availability of household vehicles,

but it is also related to the age of the vehicle. For

example, households with a household income of

$100,000 or more had a vehicle with an average

model year of 1996, while households with a

household income of less than $25,000 had a

personal vehicle with an average model year of

1991 (figure 4, table A-7). Other factors appear to

be related to the age of the household vehicle,

3 This is not a measure of the total number of registered

vehicles in the United States. Respondents to the household interview were asked about the number of vehicles

that were owned, leased, or available for regular use by

the people living in that household.

Figure 3

Proportion of Vehicles by Type

Car/station 

wagon

Van 

(mini, 

cargo, 

passenger)

SUV

Pickup 

truck

Other truck RV

Motorcycle

Other

2.5%

0.3%

0.5% 0.7%

18.3%

11.9%

9.1%

56.8%

SOURCE: The 2001 National Household Travel Survey, vehicle file, 

U.S. Department of Transportation.

Table 1

Mode of Transportation Used to Commute

to Work in the Past Week

Transportation mode Percent

Personal vehicle 91.2

Transit 4.9

Walk 2.8

Other 1.1

Total 100

SOURCE: The 2001 National Household Travel Survey, daily trip 

file, U.S. Department of Transportation.

See table A-6 for standard errors.

Figure 4

Mean Model Year by Household Income

All households

Less than $25,000

$25-49,999

$50-74,999

$75-99,999

$100,000 or more

1990 1991 1992 1993 1994 1995 1996

Household income

Mean model year

SOURCE: The 2001 National Household Travel Survey, vehicle file, 

U.S. Department of Transportation.
9

like the number of adults in the household. Singleadult households had a vehicle with an average

model year of 1993 compared to the average

model year of 1994 in households with two or

more adults, regardless of the presence of children

(table A-7). 

The next sections focus on the nature of daily

and long-distance trips in the nation. 

DAILY PASSENGER TRAVEL

The 2001 NHTS captures various aspects and

characteristics of daily and long-distance travel in

America. Data collected on daily trips include

topics such as the purpose of the trip, the means

or mode of transportation used, the duration and

length of the trip, the time of day and day of the

week when the trip took place, and the number of

people in the vehicle during the trip. In the 2001

NHTS, a daily trip is one that occurred on the

randomly selected travel day regardless of mode

or distance traveled, as long as the person went

from one address to another. This section focuses

on daily passenger travel.

Results from the 2001 NHTS show that daily

travel in the United States totaled about 4 trillion

miles (table 2, table A-8), an average of 14,500

miles per person per year. On a daily basis, the

average person traveled 40 miles, most of it (35

miles) in a personal vehicle. Because more than

one person can travel in a personal vehicle, these

35 person miles amounted to about 23 vehicle miles

traveled. Annually, the total number of vehicle

miles traveled in 2001 was nearly 2.3 trillion.4

 In

terms of number of trips, people took 411 billion

daily trips in 2001, or about 1,500 trips per person

in that year (table 2). 

Who Is Traveling? 

On a daily basis, individuals averaged about four

trips (figure 5, table A-9). Although there were no

differences in the total number of trips taken

based on gender, there were differences based on

age. The total number of trips peaked among the

working population aged 25 to 54 (4.6 trips on an

average day). Children under the age of 5 had the

fewest trips on average (3.2 trips), followed by

children between the ages of 5 and 14 and adults

over the age of 65 (figure 5, table A-9). Not surprisingly, drivers and employed adults had a

higher number of trips (4.5 trips for both groups)

compared to nondrivers and unemployed adults

(2.6 and 3.7 trips respectively) (table A-9). The

NHTS also collected information on the travel

behavior of persons 15 or older who have a medical condition that limits their travel. About 8.6

percent of persons report having a medical condition that limits their travel (table A-1).5

 As would

be expected, these persons had lower trip rates

(2.8 per day) than those who did not report any

such medical condition (4.4 per day) (table A-9).

How Do They Travel? 

The majority of daily trips occurred in personal

vehicles (87 percent) (figure 6, table A-10). About

38 percent of all trips were personal vehicle trips

with a single occupant (driver only) while 49

percent of all trips were personal vehicle trips

4 This compares to 2.1 trillion vehicle miles (standard

error 23.4 billion miles) traveled in 1995, an increase of

about 11 percent between 1995 and 2001. (1995 Nationwide Personal Transportation Survey).

Table 2

Total Daily Trips and Total Miles Traveled

in Daily Trips

Type of trips

Total trips*

(rounded to 

nearest 

billion)

Total miles**

(rounded to 

nearest 

billion)

All person trips 411 4,012

Person trips by PV 356 3,552

Vehicle trips 235 2,298

SOURCE: The 2001 National Household Travel Survey, daily trip 

file, U.S. Department of Transportation.

* In order to correctly calculate miles per trip, denominators of 403, 

350, and 233 billion trips were used for all person trips, personal 

vehicle person trips and vehicle trips respectively since not all 

cases had reported mile values associated with them.

** The total mileage represents daily household-based travel and 

therefore does not reflect a total of all passenger miles of travel in 

the United States. It does not include a) vehicle mileage from 

nondaily long-distance trips, b) noncommuting occupational trips 

(e.g., taxi cab driving), and c) is also subject to a small amount of 

nonresponse in trip mileage reporting by survey respondents.

See table A-8 for standard errors.

5 Individuals 15 and older were asked if they had a medical condition that made it difficult to travel outside the

home. This is a self reported condition, and does not

correspond to the Americans with Disabilities Act of

1990 or other formalized definition of a person with a

disability.
10

with more than one occupant. About two

percent of all trips nationwide were transit

trips.6

 School buses accounted for almost 2

percent of the trips, and walk trips

accounted for almost 9 percent of all trips.

Why Do They Travel? 

Knowing why people take trips helps urban

planners lay out residential, work, and commercial structures that minimize travel times and

distances. A large portion of trips were taken for

family and personal reasons such as shopping

and running errands (45 percent) (figure 7, table

A-11) (See glossary for definitions). Social and

recreation trips, such as vacations and visiting

friends, accounted for 27 percent of the trips.

Despite the strong focus on work and commuting

trips by researchers and urban planners, commute trips7

 accounted for about 15 percent of all

trips taken in the United States. Trips made for

work, other than the commute to and from work,

accounted for an additional 3 percent of trips.

Trips to school and church accounted for about 10

percent of all trips.

Figure 5

Mean Daily Trips by Age

Figure 6

Proportion of Trips by Mode

6 For the purpose of this report, transit is defined as

including local public bus, commuter bus, commuter

train, subway/elevated train, and street car/trolley.

All persons

65 and older

55-64 years

25-54 years

20-24 years

15-19 years

5-14 years

0-4 years

0 1 2 3 4 5

Age 

Daily trips

 Personal 

vehicle-single

 occupant

 Personal 

vehicle-multiple 

 occupant

Transit

School bus Walk Other

48.9%

37.6%

1.7% 8.6%

1.5%

1.7%

7 Commute trips are defined as those trips made for the

purpose of going to or returning from work. However,

given the definition of a daily trip, those reported as

commuting trips were not necessarily anchored by the

respondent’s home or workplace (for return commutes). Therefore, care should be taken in analyzing

work trip distances, recognizing that the distance for

these trips is often, but not always, the distance from

home to work.

Figure 7

Proportion of Trips by Purpose

Work

Workrelated

Family/

personal business

School/ 

church

Social/

recreational

Other

27.1%

9.8%

44.6%

2.9%

14.8%

0.8%

SOURCE: The 2001 National Household Travel Survey, person file, 

U.S. Department of Transportation.

SOURCE: The 2001 National Household Travel Survey, 

daily trip file, U.S. Department of Transportation.

SOURCE: The 2001 National Household Travel Survey, daily trip file, 

U.S. Department of Transportation.
11

When Do They Travel? 

Congestion is a concern for urban planners and

drivers alike. Fifty percent of adults in the United

States say that they are somewhat to severely

concerned about highway congestion (table A-1).

Daily trips (including nonpersonal vehicle trips)

are not spread evenly across the time of day,

however. Nor are strong peaks and valleys associated with the morning and evening commute

periods (figure 8, table A-12). For example, more

daily trips are taken between noon and 1 p.m.

(7.4 percent) than between 8 and 9 a.m. (5.5 percent). Daily trips are spread more evenly across

the days of the week. The fewest trips are taken

on Sunday (13 percent) compared to Friday,

when the most trips are taken (16 percent) (see

table A-13).

How Many People Are Traveling?

Vehicle occupancy can be conceptualized as a

function of both the number of people in the vehicle and the distance traveled on the trip. Thus a

trip of 12 miles has twice the weight of a 6-mile

trip. In general, the weighted (by miles traveled

in trip) occupancy rates of personal vehicle trips

in the nation is 1.6 persons per vehicle mile

(figure 9, table A-14). There are differences in

weighted occupancy based on the purpose of the

trip. Trips for social or recreational purposes have

an average weighted occupancy of 2.1 persons

per vehicle mile compared to work trips (1.1

persons per vehicle mile) (figure 9, table A-14).

Other factors affecting weighted occupancy rates

are time and day of travel. Weekday trips have a

weighted occupancy of 1.5 compared to 2 people

per vehicle mile on weekend trips (table A-15).

Experiences Behind the Wheel 

Given that a majority of daily trips are in personal

vehicles, it is of interest to know how much of an

adult’s8

 day is spent behind the wheel driving a

personal vehicle. Overall, for all adults, including

nondrivers and those who may not have driven in

a given day, 55 minutes are spent behind the wheel

driving 29 miles a day (figure 10). There are differences based on adult demographic characteristics

such as age, sex, and worker status. Even though

men and women average the same number of trips

Figure 8

Percent of Trips by Time of Day

Midnight - 1 am

1 - 2 am

2 - 3 am

3 - 4 am

4 - 5 am

5 - 6 am

6 - 7 am

7 - 8 am

8 - 9 am

9 - 10 am

10 - 11 am

11 am - noon

Noon - 1 pm

1 - 2 pm

2 - 3 pm

3 - 4 pm

4 - 5 pm

5 - 6 pm

6 - 7 pm

7 - 8 pm

8 - 9 pm

9 - 10 pm

10 - 11 pm

11 - midnight

0 1 2 3 4 5 6789

Percent of trips

Time of day

Figure 9

Mean Occupants by Trip Purpose

8 In this case, adults include all individuals ages 15 and

above, regardless of whether they are drivers or may

have driven during a given day.

All personal vehicle trips

Other

Social/recreational

Family/personal

Church/school

Work-related

Work

0 0.5 1 1.5 2 2.5

Trip purpose

Occupants

SOURCE: The 2001 National Household Travel Survey, daily trip file, 

U.S. Department of Transportation.

SOURCE: The 2001 National Household Travel Survey, daily trip 

file, U.S. Department of Transportation.
12

(4 trips) on each day, men drive further (38 v. 21

miles) and longer (67 v. 44 minutes) (table A-16

and A-17). Similarly, there are differences based on

the age of the adult—these differences mimic the

pattern of the overall total number of trips taken

(figure 10). Teenagers drive the least on an average

day—for about 25 minutes and 12 miles. Adults

over the age of 65 also drive less on an average day

compared to other adult age groups (20 to 64

years)—39 minutes and 17 miles. Adults between

the ages of 25 and 54 drive the most—64 minutes

and 35 miles a day. Workers drive further (36 v. 16

miles) and for longer (65 v. 35 minutes) compared

to nonworkers (tables A-16 and A-17).

LONG-DISTANCE TRAVEL

Long-distance trips in the 2001 NHTS are defined

as trips of 50 miles or more from home to the farthest destination traveled.9

 For a long-distance

trip, this includes both the portion of the trip to

reach the farthest destination, as well as the

return trip home and any overnight stops made

along the way or stops to change transportation

modes. Similar to daily trips, long-distance travel

includes trips made by all modes, including personal vehicle, airplane, bus, train, and ship; and

for all purposes, such as commuting, business,

pleasure, and personal or family business. 

In addition, the long-distance trip definition

has changed from the long-distance definition

used in the 1995 American Travel Survey (ATS),

where long-distance trips were defined as trips of

100 miles or more and excluded trips for the purpose of commuting. Therefore, estimates provided in this report cannot be directly compared

to estimates resulting from the 1995 ATS. 

Who Is Traveling?

Of all long-distance trips made in the United States

in 2001, fewer than half (43 percent) were made by

women (table 3). Furthermore, within any given

mode men made as many or more trips than

women, with the exception of travel by bus.

Women made 55 percent of all bus trips (out of a

total of approximately 55 million bus trips, see

table A-18b).

The majority of long-distance trips, approximately 55 percent, were made by individuals

living in households with total household

incomes of $50,000 or more per year (table A-19).

(Households with $50,000 or more in total income

represent 43 percent of the population.10) Fewer

Figure 10

Mean Minutes and Miles Spent Driving 

by Driver Age

9 Although the definitions for daily trips and long distance trips differ, it is important to note that trips made

as part of daily travel are not mutually exclusive from

long-distance travel. That is, daily trips—or combinations of daily trips into home-to-home journeys—can

result in travel of more than 50 miles or more away from

home. Therefore, these trips would be included in both

the estimates for daily travel, as well as long-distance

travel. Care should therefore be exercised when using

estimates for daily and long-distance travel together.

This is especially true of trip rates and trip miles since

simply combining would provide an overestimation of

total household travel. 

All persons 15+

65 and older

55-64 years

25-54 years

20-24 years

15-19 years

0 20 40 60 80

Driver age

Miles and minutes

Miles

Minutes

Table 3

Long-Distance Trips by Mode

and Sex, in Percent

Female Male 

Personal vehicle 42% 58%

Air 43% 57%

Bus 55% 45%

Train* 42% 58%

Other* 30% 70%

Total 43% 57%

*Differences are not significant at α=0.05.

 See table A-18a for standard errors.

SOURCE: The 2001 National Household Travel Survey, 

preliminary long distance file, U.S. Department of Transportation.

10 Household income estimates as of March 2001, Current Population Survey, March Supplement 2002. 

SOURCE: The 2001 National Household Travel Survey, daily trip file, 

U.S. Department of Transportation.
13

person trips from these households were likely

to be made in personal vehicles (87 percent)

compared to person trips from lower income

households (figure 11). For the higher income

households there were significantly more trips by

air. About 10 percent of person trips by households with an income of at least $50,000 were

made by air, compared to around 4 percent in

households with an income between $25,000 and

$49,999 and less than 3 percent for households of

less than $25,000 (table A-20). 

Nearly two-thirds of all long-distance trips

were made by persons aged 25 to 64 (table A-21).

This group represents approximately half (52

percent) of the U.S. population as of 2001.11 Onequarter of long-distance trips were made by

persons under the age of 25 (35 percent of the

U.S. population), and only about 8 percent by

those 65-years-old or older (12 percent of the

population). 

How Are They Traveling on 

Long-Distance Trips?

Nine out of 10 long-distance trips were taken in a

personal vehicle, such as a car, pickup truck, or

sports utility vehicle. In 2001, Americans took a

total of 2.3 billion long-distance trips in personal

vehicles, resulting in just over 760 billion miles of

travel on the nation’s roads (table A-22). Personal

vehicles were used for nearly 97 percent of longdistance person trips of less than 300 roundtrip

miles (table 4). On the other hand, personal vehicle trips comprised a much smaller percentage of

longer distance trips, representing a little more

than half of trips with roundtrip distances of

1,000 to less than 2,000 miles, and less than onequarter of trips 2,000 miles or greater. The median

distance for all long-distance trips taken in

personal vehicles was 194 miles (table A-22).

Air travel was the second most utilized

transportation mode for long-distance travel,

accounting for over 7 percent of long-distance

person trips. Not surprisingly, trips by air were

much more likely for trips of longer distances,

accounting for 42 percent of trips between 1,000

and 2,000 roundtrip miles, and three-quarters of

trips over 2,000 roundtrip miles (table 4). Meanwhile, air travel comprised less than half a

percent of trips of less than 500 roundtrip miles.

The median distance for air trips was 2,068

miles, 10 times that of personal vehicle trips

(table A-22).

Travel by bus was the third most popular

choice for long-distance travel, yet accounted for

only 2 percent of all long-distance trips. Similarly,

train was the next most used mode but accounted

for less than 1 percent of all long-distance trips.

The median length of a bus trip was 287 miles,

and 192 miles for train trips (table A-22).

Why Are Americans Traveling 

Long Distances?

Of all long-distance travel in 2001, over half of the

trips (56 percent) were made primarily for pleasure purposes (figure 12, table A-24a). Pleasure

trips consisted of vacations and sightseeing

excursions, as well as trips taken for the purposes

of rest and relaxation, visiting friends and family,

and outdoor recreation. More than 90 percent of

pleasure trips were by personal vehicles, another

7 percent were by air, and less than 3 percent

were by bus, train, boat, or other mode combined

(table A-24b). 

Figure 11

Proportion of Long-Distance Trips by Mode

and Household Income

11 Population estimates as of July 1, 2001. Table NAEST2002-ASRO-01—National Population Estimates—

Characteristics, Population Division, U.S. Census Bureau

(June 18, 2003) URL: http://ferret.bls.census.gov/macro/

032002/hhinc/new01_001.htm.

Other

Train

Bus

Air

0 20 40 60 80 100

Personal vehicle

Mode

Percent

$50,000 or more

$25,000-49,999

Less than $25,000

SOURCE: The 2001 National Household Travel Survey, preliminary 

long distance file, U.S. Department of Transportation.
14

The second most common reason for longdistance travel was for business purposes—trips

taken to attend conferences and meetings or for

any other business purpose other than commuting to and from work. Business trips also include

those trips where business was cited as a primary

purpose, but the traveler also included sightseeing, recreation, or other pleasure activities as

part of the trip. Nearly 16 percent of all longdistance trips, or approximately 414 million

trips, were made for business. A little less than 80

percent of these trips were by personal vehicle,

while 18 percent used a commercial or charter

airplane. Train travel accounted for about 1.6

percent and bus travel accounted for nearly 1 percent of business trips. All other modes combined

accounted for less than 1 percent of business

travel. Meanwhile, nearly 13 percent of long-distance trips in 2001 were for commuting purposes,

that is, travel of 50 miles or more away from

home to go to work. Again, personal vehicles

dominated the share of modes used for these

trips at over 96 percent. Trips taken by train and

airplane were the next most common, each representing approximately 1.5 percent of commuting

trips.

Trips made for personal reasons or family business, such as shopping trips, medical visits, and

providing rides for others, accounted for approximately 13 percent of all long-distance trips in the

nation. Although personal vehicle trips again

comprised the majority of these trips (slightly less

than 90 percent), trips made by bus and air

accounted for almost all the remaining trips at

approximately 6 and 5 percent, respectively. 

Where Are Americans Traveling? 

In 2001, Americans took about 2.6 billion longdistance trips. In total, over 1.3 trillion person

miles were logged in long-distance travel (table

A-22). The majority of these trips, about 98 percent, were to destinations in the United States

(table 5). About 16 percent of long-distance

person-miles were covered traveling to international destinations. A portion of these miles were

spent traveling on or over U.S. soil. Miles traveled

on or over U.S. soil to international destinations

are not included in the estimate of domestic miles

traveled.

Most long-distance trips (62 percent) were to

destinations within the traveler’s home state

(intrastate). Intrastate travel generated 27 percent

of all person miles for long-distance trips. Of the

remaining trips, 17 percent were to destinations

Table 4

Percent of Long-Distance Trips by Mode and Roundtrip Distance

Miles 100-299 300-499 500-999 1000-1999 2000+ Total

Personal vehicle 97.2% 94.3% 85.9% 53.9% 22.2% 89.5%

Air 0.2% 1.5% 10.3% 42.4% 74.8% 7.4%

Bus* 1.6% 3.4% 3.2% 2.6% 1.4% 2.1%

Train* 0.9% 0.7% 0.6% 0.9% 0.8% 0.8%

Other* 0.2% 0.1% 0.0% 0.1% 0.8% 0.2%

See table A-23 for standard errors.

*Differences are not significant at α=0.05.

SOURCE: The 2001 National Household Travel Survey, preliminary long distance file, U.S. Department of 

Transportation.

Figure 12

Proportion of Long-Distance Trips by Purpose

Other

Commute

Business

Pleasure

Personal 

business

0 10 20 30 40 50 60

Purpose

Percent of trips

See table A-24a for standard errors.

SOURCE: The 2001 National Household Travel Survey, preliminary 

long distance file, U.S. Department of Transportation.
15

within the same Census division and 8 percent

were to destinations in a different division but

within the same region. Eleven percent of longdistance trips were to destinations outside the

home region. (See Appendix C – Census Regions

and Divisions of the United States.)

METHODOLOGICAL CONSIDERATIONS, 

DATA RELIABILITY, AND DATA 

COMPARABILITY

Survey Methodology 

The 2001 NHTS was conducted by Westat—a

social science research firm in Rockville, Maryland—for the U.S. Department of Transportation.

The NHTS is designed to provide detailed crosssectional information on daily and long-distance

passenger travel in the United States.

Sample Design

A nationally representative sample of 60,000

individuals in 26,000 households participated in

the 2001 NHTS. The sample included all members of the household, including children under

the age of five. Sampling for the NHTS involved a

random digit dial (RDD) telephone sampling

design. 2001 NHTS data were collected from

March 2001 to May 2002. Data were collected

about all household members either directly from

the respondent or through a proxy.12 A household where 50 percent of the adults completed

the survey was considered a responding household and included in the data file. Individuals

from sampled households were asked to complete a travel diary documenting their daily trips

in order to aid in the recall process, and use the

diary when responding to the interviewer. The

overall response rate was 41 percent. (The household screener interview rate was 58 percent, and

the useable household rate was 71 percent.) 

Data Reliability

Estimates produced using data from the NHTS

are subject to two types of error, sampling and

nonsampling errors. Nonsampling errors are

errors made in the collection and processing of

data. Sampling errors occur because the data are

collected from a sample rather than a census of

the population.

Nonsampling Errors

Nonsampling error is the term used to describe

variations in the estimates that may be caused by

population coverage limitations, as well as data

collection, processing, and reporting procedures.

The sources of nonsampling errors are typically

problems like unit and item nonresponse, the

differences in respondents’ interpretations of the

meaning of the questions, response differences

related to the particular time the survey was

conducted, and mistakes in data processing. In

general, it is difficult to identify and estimate

either the amount of nonsampling error or the

Table 5

Percent of Long-Distance Trips and

Miles by Destination

Trips Miles

International 2% 16%

Different region 11% 33%

Different state,

Different division,

Same region 8% 10%

Different state,

Same division 17% 14%

Same state 62% 27%

Total 100% 100%

See table A-25 for standard errors.

12 In the NHTS data collection, an adult household member always served as the proxy for a child under age 14.

Proxies were also requested for persons age 14 and 15

years. However, if an adult household member

requested that the interviewer speak directly with these

teenagers, the interview was conducted with the subject.

Proxies were not initially requested for household members 16 years and older, but were allowed under limited

conditions. Proxy interviews were conducted for 23.4

percent of the respondents 16 and older.

SOURCE: The 2001 National Household Travel Survey, preliminary 

long distance file, U.S. Department of Transportation.
16

bias caused by this error. In the 2001 NHTS,

design efforts were made to prevent such errors

from occurring and to compensate for them

where possible. For instance, a travel diary was

used in order to aid with the recall of daily trips.

In addition, details on the travel day were

collected within six days of it occurring while

events of that day were still relatively fresh in the

minds of the respondents. Other more standard

procedures, such as online, computer-assisted

telephone interview (CATI) editing were used as

well.

Standard Errors and Weights

In order to produce national estimates from the

2001 NHTS data, the sample data were weighted.

Weighting the data adjusts for selection probabilities at the household level and adjusts for household and individual nonresponse. The 2001

NHTS data files contain two kinds of weights; 

1. from “usable” households in which person

interviews were completed with at least 50

percent of adults in the household (26,038

households in the sample), and 

2. “100 percent” households in which person

interviews were completed with all adults

in the household (22,178 households in the

sample). 

All estimates in this report are weighted.13 In

addition to properly weighting the responses,

special procedures for estimating the statistical

significance of the estimates were employed

because the data were collected using a complex

sample design. Complex sample designs, like that

used in the NHTS and other large-scale federal

surveys, result in data that do not comply with

the assumptions normally required to assess the

statistical significance of the results. Frequently,

the standard errors of the estimates are larger

than would be expected if the sample was a simple random sample and the observations were

independent and identically distributed random

variables. Replication methods of variance estimation were used to reflect the actual sample

design used in the 2001 NHTS. A form of the jackknife replication method (JK2) using 99 replicates

was used to compute approximately unbiased

estimates of the standard errors of the estimates

in the report, using the statistical software WesVarPC. The jackknife methods were used to estimate the precision of the estimates of the reported

national percentages and means.

Statistical Procedures

 Comparisons made in the text were tested for statistical significance to ensure that the differences

are larger than might be expected due to sampling

variation. All differences described in the text are

statistically significant at a 0.05 level. When comparing estimates between categorical groups (e.g.,

sex, income), the difference in the estimates (mean

or percent) was computed along with a confidence

interval. If the confidence interval contained the

value of zero, then the estimates had no detectable

statistically significant difference. 

The confidence interval of the difference of two

proportions was computed as: 

(Est1 – Est2) +/- (1.96 * SQRT[(se1)

2

 + (se2)

2

])

The confidence interval of the difference of two

means was computed as:

(Est1-Est2) +/- (1.96* SQRT[((se1)

2

) + ((se2)

2

)])

where Est1 and Est2 are the independent estimates being compared, and se1 and se2 are their

corresponding standard errors. 

Data Comparability: Changes from 

Prior Surveys

The 2001 survey represents a combined survey of

the National Personal Transportation Survey

(NPTS) and the ATS (American Travel Survey).

The ATS, conducted in 1995 by the Census

Bureau for BTS, was a survey of trips of 100 miles

or more taken over the course of a calendar year.

There were methodological difficulties in trying

to use the 1995 NPTS and the 1995 ATS together

to form a picture of total household travel by the

American public. The combined survey approach

for the 2001 NHTS was designed to resolve this

13 Weights used in this report: The 50 percent daily

travel and person weights (WTTRDFIN and WTPERFIN) and the 50 percent travel period weights (WTTPFIN) were used. WTPERFIN sums to the population of

all noninstitutionalized individuals in the United States

while WTTRDFIN and WTTPFIN sum to the annualized

estimate of the total number of daily and long-distance

trips taken by individuals in the nation.
17

by providing one data source for the full continuum of person travel. In addition to combining

the two surveys, the threshold for longer trips

was lowered to 50 miles or more to obtain a better

sample of the often-overlooked trips in the 50- to

100-mile range.

For the first time in the NPTS series, travel

data were collected for household members

under the age of five years. All previous surveys

collected travel only from household members

age five and older, on the assumption that

children under the age of five only made trips

with other household members. However, this

overlooked trips made by this young group with

day care providers as part of a preschool activity,

or with other nonhousehold members. 

There are many differences in questionnaire

format that affect estimates. For example, in the

2001 NHTS, a specific probe was included about

walking trips to more accurately capture such

trips. As a result, it is possible that the increase in

the proportion of all trips that are walk trips compared to the 1995 NPTS may be due to this additional probe, rather than a true increase in the

actual numbers of walk trips.

In addition to changes in the survey design

and administration, other factors affected travel

behavior and possibly data collection during the

2001 NHTS. The September 11, 2001 attacks on

the World Trade Center Towers and the Pentagon,

the security measures that followed, and the

ensuing sense of insecurity in the nation severely

disrupted travel in the United States for months,

changing the amount and modes of travel during

that period. In addition, during the last few

months of 2001, the public's suspicion regarding

unanticipated mail packages was heightened

after letters containing anthrax were sent to individuals through the mail. Although the impact of

this on travel is yet to be determined, it may have

affected 2001 NHTS response rates because the

survey had a mail component.

Further information on the survey, sample

design, comparability with past surveys, data

editing and process, data file structures, weight,

etc. is available in the 2001 NHTS User’s Guide

that will be released with the data.
 
19

Appendix A —Tables with Estimates 

Used in the Report and Standard Errors

The following tables show the estimates and their

accompanying standard errors. Standard errors

(SE) are in the same metric as the estimates. All

comparisons in the text are statistically significant

at a 0.05 level unless otherwise noted.

Section II. Household, Individual, and Vehicle Characteristics

Table A-1

Travel Related Characteristics of Individuals 15 and Older, in Percent

Percent SE

Drivers 88 0.18

Used public transit in last 2 months 17 0.23

Biked in the last week 8 0.18

Have travel-affecting medical condition 9 0.14

Are somewhat to severely concerned about highway congestion 50 0.35

NOTES: Percents do not total 100% since categories are not mutually exclusive. SE = standard error.

SOURCE: The 2001 National Household Travel Survey, person file, U.S. Department of Transportation.

Table A-2

Mean Number of Drivers, Vehicles, and Bicycles

per Household

Mean SE

Drivers per household 1.75 0.005

Personal vehicles per household 1.90 0.007

Adult-size bicycles per 

household 0.86 0.009

NOTE: SE = standard error.

SOURCE: The 2001 National Household Travel Survey, household 

file, U.S. Department of Transportation.
20 APPENDIX A

 

Table A-3

Mean Number of Personal Vehicles by Number

of People in the Household

(see Figure 1 in text)

Mean SE

One person 1.01 0.010

Two people 1.98 0.011

Three people 2.31 0.023

Four people 2.39 0.023

Five people 2.48 0.040

Six people 2.50 0.074

Seven or more people 2.76 0.113

NOTE: SE = standard error.

SOURCE: The 2001 National Household Travel Survey, 

household file, U.S. Department of Transportation.

Table A-4

Percent and Characteristics of Zero-Vehicle 

Households

(see Figure 2 in text)

Percent SE

All households 7.9 0.20

Household income less than 

$25,000 20.3 0.62

Household income of $25,000

or more 2.3 0.17

Residence is rented 17.6 0.52

Residence is owned/other 3.0 0.16

Residence is a condominium/

apartment 21.8 0.69

Residence is not a condominium/

apartment 4.0 0.17

Single-person household 18.7 0.59

Multiperson household 4.1 0.19

Household in rural area 3.6 0.35

Household in urban area 9.0 0.23

NOTE: SE = standard error.

SOURCE: The 2001 National Household Travel Survey, household 

file, U.S. Department of Transportation.

Table A-5

Distribution of Household Personal Vehicles by 

Type, in Percent

(see Figure 3 in text)

Percent SE

Car/station wagon 56.8 0.29

Van (mini, cargo, passenger) 9.1 0.14

Sport utility vehicle 11.9 0.16

Pickup truck 18.3 0.21

Other truck 0.5 0.04

Recreational vehicle 0.7 0.03

Motorcycle 2.5 0.08

Other 0.3 0.03

Total 100.0

NOTE: SE = standard error.

SOURCE: The 2001 National Household Travel Survey, vehicle 

file, U.S. Department of Transportation.

Table A-6

Mode of Transportation Used to Commute to Work

in the Past Week, in Percent

Percent SE

Personal vehicle 91.2 0.25

Transit 4.9 0.19

Walk 2.8 0.12

Other 1.1 0.10

Total 100.0

NOTE: SE = standard error.

SOURCE: The 2001 National Household Travel Survey, person 

file, U.S. Department of Transportation.

Table A-7

Mean Personal Vehicle Model Year by Household 

Income and Number of Adults in Household

(see Figure 4 in text)

Mean SE

All households 1993.6 0.035

Household income

Less than $25,000 1991.3 0.098

$25,000-$49,999 1993.0 0.066

$50,000-$74,999 1994.2 0.089

$75,000-$99,999 1994.9 0.089

$100,000 or more 1995.7 0.077

Number of adults

Two or more adults 1993.7 0.037

One adult 1992.9 0.089

NOTE: SE = standard error.

SOURCE: The 2001 National Household Travel Survey, vehicle 

file, U.S. Department of Transportation.
APPENDIX A 21

Section III. Daily Passenger Travel 

Table A-8

Total Daily Trips and Total Miles Traveled in Daily Trips, in Billions

Total trips* SE Total miles** SE

All person trips 411 1.9 4,012 44.9

Person trips by personal vehicle 356 1.9 3,552 41.3

Vehicle trips 235 1.4 2,298 24.4

* In order to correctly calculate miles per trip, denominators of 403, 350, and 233 billion trips were used for all person trips, 

personal vehicle person trips, and vehicle trips respectively because not all cases had reported mile values associated with 

them.

** The total mileage represents daily household-based travel and therefore does not reflect a total of all passenger miles of travel 

in the United States. It does not include a) vehicle mileage from nondaily long-distance trips, b) noncommuting occupational 

trips (e.g., taxi cab driving), and c) is also subject to a small amount of nonresponse in trip mileage reporting by survey 

respondents.

NOTE: SE = standard error.

SOURCE: The 2001 National Household Travel Survey, daily trip file, U.S. Department of Transportation.

Table A-9

Mean Number of Trips by All Persons by Sex,

Age, Driver Status, Worker Status, 

and Medical Condition

(see Figure 5 in text)

Mean SE

All persons 4.1 0.02

Sex

Male 4.1 0.02

Female 4.1 0.02

Age

Less than 5 years 3.2 0.05

5-14 years 3.5 0.04

15-19 years 4.0 0.06

20-24 years 4.1 0.07

25-54 years 4.6 0.02

55-64 years 4.1 0.05

65 years and older 3.4 0.04

Driver status*

Yes, a driver 4.5 0.02

Not a driver 2.6 0.04

Employment status*

Employed 4.5 0.02

Not employed 3.7 0.03

Medical condition*

Medical condition limits travel 2.8 0.06

No medical condition limiting travel 4.4 0.02

*Asked of persons age 15 and older.

NOTE: SE = standard error.

SOURCE: The 2001 National Household Travel Survey, person 

file, U.S. Department of Transportation.

Table A-10

Distribution of Trips by Mode of Transportation,

in Percent

(see Figure 6 in text)

Percent SE

Personal vehicle (PV) 86.6 0.18

PV-single occupant 37.6 0.25

PV-multiple occupants 48.9 0.28

Transit 1.5 0.06

School bus 1.7 0.05

Walk 8.6 0.13

Other 1.7 0.07

Total 100.0

NOTE: SE = standard error.

SOURCE: The 2001 National Household Travel Survey, daily trip 

file, U.S. Department of Transportation.

Table A-11

Distribution of Trips by Trip Purpose, in Percent

(see Figure 7 in text)

Percent SE

Work 14.8 0.12

Work-related 2.9 0.08

Family/personal business 44.6 0.22

School/church 9.8 0.11

Social/recreational 27.1 0.21

Other 0.8 0.03

Total 100.0

NOTE: SE = standard error.

SOURCE: The 2001 National Household Travel Survey, daily trip 

file, U.S. Department of Transportation.
22 APPENDIX A

Table A-12

Distribution of Trips by Time of Day, in Percent

(see Figure 8 in text)

Trip start time Percent SE

Midnight-1 a.m. 0.4 0.02

1 - 2 a.m. 0.2 0.01

2 - 3 a.m. 0.2 0.01

3 - 4 a.m. 0.1 0.01

4 - 5 a.m. 0.4 0.02

5 - 6 a.m. 1.0 0.03

6 - 7 a.m. 2.6 0.05

7 - 8 a.m. 6.2 0.08

8 - 9 a.m. 5.5 0.08

9 - 10 a.m. 4.9 0.07

10 - 11 a.m. 5.9 0.08

11 a.m - 12 p.m. 6.6 0.08

12 - 1 p.m. 7.4 0.08

1 - 2 p.m. 6.6 0.07

2 - 3 p.m. 7.3 0.09

3 - 4 p.m. 8.3 0.09

4 - 5 p.m. 7.8 0.08

5 - 6 p.m. 7.9 0.09

6 - 7 p.m. 6.7 0.09

7 - 8 p.m. 5.2 0.08

8 - 9 p.m. 3.9 0.07

9 - 10 p.m. 2.8 0.06

10 - 11 p.m. 1.6 0.05

11 - 12 p.m. 0.9 0.03

Total 100.0

NOTES: More accurately the categories are Midnight to 00:59 

a.m., 1 a.m. to 1:59 a.m., etc. SE = standard error.

SOURCE: The 2001 National Household Travel Survey, daily trip 

file, U.S. Department of Transportation.

Table A-13

Distribution of Daily Trips by Day of the Week, 

in Percent

Percent SE

Sunday 12.9 0.16

Monday 13.8 0.16

Tuesday 14.0 0.15

Wednesday 14.7 0.16

Thursday 14.6 0.15

Friday 15.6 0.17

Saturday 14.5 0.18

Total 100.0

NOTE: SE = standard error.

SOURCE: The 2001 National Household Travel Survey, daily trip 

file, U.S. Department of Transportation.

Table A-14

Vehicle Occupancy Per Vehicle Mile 

by Daily Trip Purpose

(see Figure 9 in text)

Mean SE

All personal vehicle trips 1.63 0.012

Work 1.14 0.007

Work-related 1.22 0.020

Family/personal 1.81 0.016

Church/school 1.76 0.084

Social/recreational 2.05 0.028

Other 2.02 0.130

NOTE: SE = standard error.

SOURCE: The 2001 National Household Travel Survey, daily trip 

file, U.S. Department of Transportation.
APPENDIX A 23

Table A-15

Vehicle Occupancy Per Vehicle Mile by Time of Day

and Weekend Status

Mean SE

All personal vehicle trips 1.63 0.010

Trip start time

Midnight-1 a.m. 1.47 0.065

1 - 2 a.m. 1.54 0.108

2 - 3 a.m. 1.98 0.288

3 - 4 a.m. 1.26 0.109

4 - 5 a.m. 1.54 0.128

5 - 6 a.m. 1.30 0.047

6 - 7 a.m. 1.30 0.030

7 - 8 a.m. 1.33 0.020

8 - 9 a.m. 1.64 0.084

9 - 10 a.m. 1.58 0.043

10 - 11 a.m. 1.74 0.052

11 a.m - 12 p.m. 1.66 0.028

12 - 1 p.m. 1.74 0.033

1 - 2 p.m. 1.69 0.043

2 - 3 p.m. 1.67 0.029

3 - 4 p.m. 1.65 0.025

4 - 5 p.m. 1.64 0.039

5 - 6 p.m. 1.62 0.033

6 - 7 p.m. 1.78 0.032

7 - 8 p.m. 1.86 0.042

8 - 9 p.m. 1.85 0.047

9 - 10 p.m. 1.84 0.057

10 - 11 p.m. 1.64 0.050

11 - 12 a.m. 1.63 0.042

Weekend status

Weekend 2.00 0.030

Weekday 1.50 0.010

NOTES: More accurately the categories are Midnight to 00:59 

a.m., 1 a.m. to 1:59 am, etc. SE = standard error.

SOURCE: The 2001 National Household Travel Survey, daily trip 

file, U.S. Department of Transportation.

Table A-16

Minutes Spent Driving Daily by Persons 15 and 

Older by Sex, Age and Worker Status

(see Figure 10 in text)

Minutes SE

All persons 15 and older 55.1 0.39

Sex

Male 67.3 0.61

Female 43.8 0.41

Age

15-19 years 24.6 0.91

20-24 years 51.7 1.48

25-54 years 64.1 0.58

55-64 years 57.7 0.90

65 years and older 39.3 0.76

Worker status

Employed 65.1 0.51

Not employed 34.5 0.48

NOTE: These estimates include nondrivers and those who did not 

drive on a given travel day who were 15 years old and older. SE = 

standard error.

SOURCE: The 2001 National Household Travel Survey, daily trip 

and person file, U.S. Department of Transportation.

Table A-17

Miles Driven Daily by Persons 15 and Older

by Sex, Age and Worker Status 

(see Figure 10 in text)

Miles SE

All persons 15 and older 29.1 0.31

Sex

Male 37.6 0.50

Female 21.2 0.28

Age

15-19 years 12.2 0.51

20-24 years 28.9 1.21

25-54 years 35.0 0.48

55-64 years 29.7 0.61

65 years and older 17.0 0.45

Worker status

Employed 35.5 0.41

Not employed 16.0 0.33

NOTE: These estimates include nondrivers and those who did not 

drive on a given travel day who were 15 years old and older. SE = 

standard error.

SOURCE: The 2001 National Household Travel Survey, daily trip file 

and person file, U.S. Department of Transportation.
24 APPENDIX A

Section IV. Long-Distance Travel

Table A-18a

Long-Distance Trips by Mode and Sex,

in Percent

Female Male

Percent SE Percent SE

Personal vehicle 42.3 0.52 57.7 0.52

Air 42.6 1.14 57.4 1.14

Bus 54.9 2.75 45.1 2.75

Train 42.3 6.73 57.7 6.73

Other 30.4 9.07 69.6 9.07

NOTE: SE = standard error.

SOURCE: The 2001 National Household Travel Survey, 

preliminary long-distance trip file, U.S. Department of 

Table A-18b

Long-Distance Trips by Mode and Sex, in Millions

Female Male Total

Trips SE Trips SE Trips SE

Personal Vehicle 989.0 14.82 1,347.1 28.90 2,336.1 36.89

Air 82.3 3.59 111.0 4.07 193.3 6.28

Bus 30.4 2.41 25.0 2.19 55.4 3.45

Train 9.0 1.43 12.2 2.53 21.1 2.88

Other 1.8 0.34 4.0 1.38 5.8 1.45

Total 1,112.4 15.49 1,499.3 29.45 2,611.7 37.70

NOTE: SE = standard error.

SOURCE: The 2001 National Household Travel Survey, preliminary long-distance trip file, U.S. Department of 

Transportation.

Table A-19

Long-Distance Trips by Household Income,

in Percent

Percent SE

Less than $25,000 13.1 0.55

$25,000-$49,999 30.1 0.77

$50,000 or more 56.7 0.77

Total 100.0

NOTE: SE = standard error.

SOURCE: The 2001 National Household Travel Survey, preliminary 

long-distance trip file, U.S. Department of Transportation.
APPENDIX A 25

Table A-20

Long-Distance Trips by Mode and Household Income, in Percent

Less than $25,000 $25,000 to $49,999 $50,000 or more Total

Percent SE Percent SE Percent SE Percent SE

Personal vehicle 92.3 0.81 93.3 0.40 87.1 0.43 89.7 0.33

Air 3.0 0.34 3.8 0.29 10.2 0.38 7.3 0.27

Bus 3.7 0.57 2.1 0.21 1.7 0.16 2.1 0.13

Train 0.7 0.22 0.6 0.18 0.8 0.13 0.7 0.09

Other 0.3 0.28 0.1 0.05 0.2 0.06 0.2 0.05

Total 100.0 100.0 100.0 100.0

NOTE: SE = standard error.

SOURCE: The 2001 National Household Travel Survey, preliminary long-distance trip file, U.S. Department of Transportation.

Table A-21

Long-Distance Trips by Age, in Percent

Percent SE

Under 25 25.7 0.49

25-64 65.8 0.52

65 or older 8.5 0.26

Total 100.0

NOTE: SE = standard error.

SOURCE: The 2001 National Household Travel Survey, 

preliminary long-distance trip file, U.S. Department of 

Transportation.

Table A-22

Long-Distance Trips and Trip Miles by Mode, in Millions

 Total trips 

(Millions) SE

 Median 

miles SE

 Total miles 

(Millions) SE

Personal vehicle 2,336.1 36.89 194 3 760,324.7 11,695.33

Air 193.3 6.28 2,068 45 557,609.3 25,375.76

Bus 55.4 3.45 287 20 27,081.3 3,048.33

Train 21.1 2.88 192 26 10,546.0 1,998.44

Other 5.8 1.45 188 48 5,117.9 1,123.89

Total 2,611.7 37.70 210 3 1,360,679.1 28,295.42

NOTE: SE = standard error.

SOURCE: The 2001 National Household Travel Survey, preliminary long-distance trip file, U.S. Department of Transportation.
26 APPENDIX A

Table A-23

Long-Distance Trips by Mode and Distance, in Percent

 100-299 miles 300-499 miles 500-999 miles 1,000-1,999 miles 2,000+ miles

Percent SE Percent SE Percent SE Percent SE Percent SE

Personal

vehicle 97.2 0.24 94.3 0.45 85.9 0.83 53.9 1.90 22.2 1.47

Air 0.2 0.05 1.5 0.27 10.3 0.78 42.4 1.91 74.8 1.54

Bus 1.6 0.15 3.4 0.35 3.2 0.37 2.6 0.60 1.4 0.42

Train 0.9 0.16 0.7 0.19 0.6 0.19 0.9 0.50 0.8 0.32

Other 0.2 0.07 0.1 0.08 0.0 0.03 0.1 0.08 0.8 0.24

Total 100.0 100.0 100.0 100.0 100.0

NOTE: SE = standard error.

SOURCE: The 2001 National Household Travel Survey, preliminary long-distance trip file, U.S. Department of Transportation.

Table A-24a

Long-Distance Trips by Purpose, in Percent

Percent SE

Commute 12.7 0.83

Business 15.9 0.50

Pleasure 55.5 0.76

Personal Business 12.6 0.41

Other 3.4 0.20

Total 100.0

NOTE: SE = standard error.

SOURCE: The 2001 National Household Travel Survey, 

preliminary long-distance trip file, U.S. Department of 

Transportation.

Table A-24b

Long-Distance Trips by Mode and Purpose, in Percent

Commute Business Pleasure

Personal 

business Other

Percent SE Percent SE Percent SE Percent SE Percent SE

Personal vehicle 96.4 0.79 79.3 1.08 90.4 0.36 89.3 0.71 96.6 0.83

Air 1.5 0.35 17.8 0.94 6.7 0.29 4.7 0.44 1.9 0.64

Bus 0.5 0.25 0.8 0.25 2.2 0.19 5.6 0.53 0.5 0.25

Train 1.7 0.69 1.6 0.37 0.5 0.08 0.3 0.13 0.0 0.04

Other 0.0 0.00 0.5 0.28 0.2 0.04 0.1 0.05 1.0 0.53

Total 100.0 100.0 100.0 100.0 100.0

NOTE: SE = standard error.

SOURCE: The 2001 National Household Travel Survey, preliminary long-distance trip file, U.S. Department of Transportation.
APPENDIX A 27

Table A-25

Long-Distance Trips and Miles by Destination, 

in Percent

 Trips 

(Percent) SE

 Miles 

(Percent) SE

International 2.2 0.15 16.4 1.29

Different region 10.9 0.36 33.3 0.98

Different state,

different 

division,

same region 7.5 0.29 9.9 0.42

Different state,

same division 17.0 0.49 13.8 0.53

Same state 62.4 0.63 26.7 0.67

Total 100.0 100.0

NOTE: SE = standard error.

SOURCE: The 2001 National Household Travel Survey, 

preliminary long-distance trip file, U.S. Department of 

Transportation.
 
APPENDIX B 29

Appendix B—Glossary

Census Division: The classification is derived

from the household's home address and is based

on the 2000 Census definitions. The nine categories are:

1. New England (ME, NH, VT, CT, MA, RI)

2. Mid-Atlantic (NY, NJ, PA)

3. East North Central (IL, IN, MI, OH, WI)

4. West North Central (IA, KS, MO, MN, ND,

NE, SD)

5. South Atlantic (DC, DE, FL, GA, MD, NC,

SC, WV, VA)

6. East South Central (AL, KY, MS, TN)

7. West South Central (AR, LA, OK, TX)

8. Mountain (AZ, CO, ID, MT, NM, NV, UT,

WY)

9. Pacific (AK, CA, HI, OR, WA)

Census region: The classification is derived from

the household's home address and is based on the

2000 Census definitions. The four categories are:

1. Northeast (CT, MA, ME, NH, NJ, NY, PA, RI,

VT)

2. Midwest (IA, IL, IN, KS, MI, MO, MN, ND,

NE, OH, SD, WI)

3. South (AL, AR, DC, DE, FL, GA, KY, LA,

MD, MS, NC, OK, SC, TN, TX, WV, VA) 

4. West (AK, AZ, CA, CO, HI, ID, MT, NM, NV,

OR, UT, WA, WY)

Person miles of travel (PMT): The number of

miles traveled by all persons on the trip. For

example, two people making a five-mile trip in

one car would generate 10 person miles.

Person trip: A trip made by one person by any

mode and for any purpose. (See definition of trip

for differences between daily and long-distance

trips.)

Privately owned vehicle (POV) or Personal

Vehicle (PV): This mode of transportation

includes all personal vehicles owned or available

to the household such as cars, vans, pickup

trucks, other trucks, recreational vehicles, and

motorcycles. Private aircrafts or boats are not

included in this category.

Transit: This category includes the following

modes of transportation—local public transit

buses, commuter buses, commuter trains, subway/elevated trains, street car/trolleys. Because

of a detailed breakdown of categories available

on the 2001 NHTS, the definition of transit no

longer includes charter, tour, and courtesy buses.

Trip: Trips are defined differently in the daily and

long-distance trip segments. Regular trips (more

than 10 a day) that were part of a person’s

employment—e.g., trips by a taxi driver were not

collected in either component.
30 APPENDIX B

Daily trip: On the daily travel component a trip is

defined as going from one address to another,

other than changing the mode of transportation.

A daily trip does not have to originate from

home, and can begin from the last address

traveled. 

Long-distance trip: In the travel period (long

distance) component, a long-distance trip is

defined as a trip of 50 miles or more away from

home. This includes the portions of the trip from

the home to farthest destination, as well as the

return trip home and any overnight stops or

changes in transportation made along the way.

Trip purpose: A trip purpose is the reason that

motivates the travel. For this report, the following

sets of trip categories were used for daily and

long-distance trips respectively.

Daily trip:

Family and Personal Business—Includes trips for

the purpose of window shopping or purchase of

goods, doctor or dentist visits, picking up or

dropping off someone else, and other personal

reasons, such as the purchase of services, haircuts, banking, and car repair.

School/Church—Trips to school, college or university classes, or to attend religious activities. 

Social and Recreations—Includes trips taken as

vacation, to visit friends and relatives, and other

activities such as participating in sports, and

going to movies or other entertainment venues. 

Work—Trips to and from one’s place of work,

or where one reports to work.

Work Related—Trips made for one’s job, other

than travel to and from the place of work. This

may include going to a meeting, conference, or

visiting clients.

Long-distance trip:

Business—This category includes trips taken to

attend conferences and meetings or for any other

business purpose other than commuting to and

from work. Trips are classified as business so long

as business is the primary purpose, even though

the traveler may have done some sightseeing or

other pleasure activities.

Pleasure—This category includes vacations,

sightseeing excursions, as well as trips taken for

the purposes of rest and relaxation, visiting

friends and family or outdoor recreation.

Personal and Family Business—This category

includes medical visits, shopping trips, and trips

to attend weddings, funerals, etc. 

Work—Trips to and from work, commonly

referred to as commuting trips.

Vehicle miles of travel (VMT): Each mile traveled by a privately owned vehicle without regard

to the number of occupants in the vehicle. For

example, two people making a five-mile car trip

would generate five vehicle miles of travel.

Vehicle trips: A vehicle trip includes all trips

made by a privately owned vehicle without

regard to the number of occupants in the vehicle.
APPENDIX C 31

Appendix C–Census Regions and Divisions

of the United States

Region

DC

WA

MT

OR

CA

NV

AZ

CO

SD

KS

TX

IL

MI

IN OH

GA

FL

NC

VA

ME

MA

RI

CT

NJ

DE

MD

NY

PA

HI

VT NH

Division

State

AK

NM

UT

ID

WY NE

ND

OK

MO

IA

MN

WI

LA

AR

MS AL

TN

KY

SC

WV

NV

CA

WEST

MIDWEST

NORTHEAST

SOUTH

PACIFIC

PACIFIC

MOUNTAIN

 WEST 

 NORTH 

CENTRAL EAST 

 NORTH 

CENTRAL

 WEST 

 SOUTH 

CENTRAL

 EAST 

 SOUTH 

CENTRAL

 SOUTH 

ATLANTIC

 NEW 

ENGLAND

 NORTH 

ATLANTIC