Introduction to the 2009 NHTS
The 2009 National Household Travel Survey (NHTS) provides information to assist transportation planners and policy makers who need comprehensive data on travel and transportation patterns in the United States. The 2009 NHTS updates information gathered in the 2001 NHTS and in prior Nationwide Personal Transportation Surveys (NPTS) conducted in 1969, 1977, 1983, 1990, and 1995.
The NHTS/NPTS serves as the nation's inventory of daily travel. Data is collected on daily trips taken in a 24-hour period, and includes:
- purpose of the trip (work, shopping, etc.);
- means of transportation used (car, bus, subway, walk, etc.);
- how long the trip took, i.e., travel time;
- time of day when the trip took place;
- day of week when the trip took place; and
if a private vehicle trip:
- number of people in the vehicle , i.e., vehicle occupancy;
- driver characteristics (age, sex, worker status, education level, etc.); and
- vehicle attributes (make, model, model year, amount of miles driven in a year).
These data are collected for:
- all trips,
- all modes,
- all purposes,
- all trip lengths, and
- all areas of the country, urban and rural.
Uses of the NHTS
NHTS data are used to:
- quantify travel behavior,
- analyze changes in travel characteristics over time,
- relate travel behavior to the demographics of the traveler, and
- study the relationship of demographics and travel over time.
The NHTS data are used primarily for gaining a better understanding of travel behavior. The data enable DOT officials to assess program initiatives, review programs and policies, study current mobility issues, and plan for the future.
The NHTS is a tool in the urban transportation planning process; it provides data on personal travel behavior, trends in travel over time, trip generation rates, national data to use as a benchmark in reviewing local data, and data for various other planning and modeling applications.
The transportation research community, including academics, consultants and government, use the NHTS extensively to examine:
- travel behavior at the individual and household level;
- the characteristics of travel, such as trip chaining, use of the various modes, amount and purpose of travel by time of day and day of week, vehicle occupancy, and a host of other attributes;
- the relationship between demographics and travel; and
- the public's perceptions of the transportation system.
People in various fields outside of transportation use the NHTS data to connect the role of transportation with other aspects of our lives. Medical researchers use the data to determine crash exposure rates of drivers and passengers, including the elderly, who have heightened morbidity and mortality rates. Safety specialists study the accident risk of school-age children, particularly when they are traveling on their own by walking or biking. Social service agencies need to know more about how low-income households currently meet their travel needs.
Scope – What the NHTS Includes
The 2009 NHTS data set includes, but is not limited to:
- household data on the relationship of household members, education level, income, housing characteristics, and other demographic information;
- information on each household vehicle, including year, make, model, and estimates of annual miles traveled;
- data about drivers, including information on travel as part of work;
- data about one-way trips taken during a designated 24-hour period (the household's travel day) including the time the trip began and ended, length of the trip, composition of the travel party, mode of transportation, purpose of the trip, and the specific vehicle used (if a household vehicle);
- information to describe characteristics of the geographic area in which the sample household and workplace of sample persons are located;
- data on telecommuting;
- public perceptions of the transportation system;
- data on Internet usage; and
- the typical number of transit, walk and bike trips made over a period longer than the 24-hour travel day.
Scope – What Is Not Included
In the past there have been many requests for data that are closely related to, but are not available in the survey. Examples of the most common requests for data that are not included in NHTS are:
- information on costs of travel;
- information about specific travel routes or types of roads used;
- travel of the sampled household changes over time;
- information that would identify the exact household or workplace location; and
- the traveler's reason for selecting a specific mode of travel over another mode.
States and MPOs have the unique opportunity to purchase samples of the household travel survey when it is conducted, approximately every five to seven years. These additional samples, along with random national samples collected in the Add-on area, are compiled into a cleaned geocoded database for ready application to local planning and forecasting. Trips of ALL lengths, for ALL purposes, and for ALL modes are collected. Read more...
Design, Implementation, and Sample
The design was a list-assisted random digit dialing (RDD) computer-assisted telephone interviewing (CATI) survey conducted over an entire year. Travel data were collected from the civilian, non-institutional, non-institutionalized population of the United States. People living in medical institutions, prisons, and in barracks on military bases were excluded from the sample. For more information, please see the User's Guide.
2001 NHTS (National Household Travel Survey)
For the 2001 NHTS, FHWA (Federal Highway Administration) and BTS (Bureau of Transportation Statistics) funded a pretest to determine whether the Nationwide Personal Transportation Survey (NPTS) (focus on daily travel) should be combined with the American Travel Survey (ATS) (focus on long-distance travel). Both survey instruments were redesigned to better suit the objectives of the 2000 data collection effort. The findings of this pretest resulted in the 2001 NHTS being a combined NPTS/ATS survey, and the survey name was changed to flag that content change.
The 2001 NHTS sample was comprised of 26,038 national samples and 43,779 households in nine Add-on areas, for a total of 69,817 interviewed households.
For long trips, a four-week recall period was used and data were collected on all trips of 50 miles or more from home. The 2001 survey collected travel data for all household members, including 0-4 year olds. Additionally, the definition of a travel day trip was modified to explicitly exclude stops to change mode of transportation, to obtain more detail on trip purposes, to use a cash incentive in the pre-household interview mailing, and to make additional modes available to collect odometer readings (i.e., Internet, facsimile and a toll-free number).
The 2001 NHTS funding was provided by FHWA, BTS, and NHTSA (National Highway Transportation Safety Administration).
See the 2001 NHTS User's Guide for additional information.
1995 NPTS (National Personal Transportation Survey)
In preparation for the 1995 NPTS, a large pretest was conducted to identify problems with new questions, determine the average interview time, and test the data collection procedures. A methodological experiment was embedded within the pretest sample in order to test three methods to collect travel day data: pure recall, memory jogger, and travel diary. The pretest showed that the use of travel diaries would lead to more complete NPTS trip reporting, thus a one-day trip diary was used in the 1995 NPTS. In addition, a household roster of trips allowed the CATI interviewer to skip trip detail for a specific respondent if another household member had already reported information about that trip.
Mailing advance letters served to inform the sample households of their selection for the 1995 NTPS, legitimized the survey and presented it in the larger context, and notified them that an interviewer would telephone their household to interview the members.
The 1995 survey included new questions to:
- measure the public's perceptions of, or satisfaction with, the nation's transportation system;
- determine respondent's usual modes of travel;
- elicit their reactions to statements about mobility and congestion;
- identify perceived difficulties in travel;
- collect information on the use of seat belts;
- describe the household's location, type of structure, and tenure; and
- improve trip purpose coding.
The 1995 NPTS sample consisted of 21,000 households in the national sample and 21,033 households in four Add-on jurisdictions, for a total of 42,033 interviewed households.
As with previous surveys in the series, the 1995 NPTS included collecting daily trips as well as longer trips of 75 miles or more taken over the previous two weeks. The 1995 NPTS was funded by FHWA, NHTSA, OST (Office of the Secretary of Transportation), FTA (Federal Transit Administration) and FRA (Federal Railroad Administration).
See the 1995 NPTS User's Guide for additional information.
1990 NPTS (National Personal Transportation Survey)
The 1990 NPTS marked the first time the survey was conducted by a private firm, Research Triangle Institute (RTI), using a computer-assisted telephone interviewing (CATI) technology. This was a significant change from the in-home interview methodology previously used for the NPTS. The national sample consisted of 18,000 households. One state and two Metropolitan Planning Organizations purchased additional interviews in their areas, increasing the total completed sample to 22,317 households. This represented the start of the Add-on component of the NPTS.
Other methodology changes in 1990 were:
- the use of the random-digit dialing (RDD) sampling procedures (moving from an address sample to a telephone number sample),
- greater utilization of proxy respondents, and
- an increase in the allowable window for interviewing sampled persons about their travel from four to six days.
The 1990 NPTS included new questions about vehicle accidents that members of the household had experienced and the highway types used for selected vehicle trips on the household's travel day. The core data components, however, were comparable to previous surveys in the series as was survey sponsorship. The 1990 NPTS was funded by FHWA, NHTSA, OST, and FTA.
See the 1990 NPTS User's Guide for additional information.
1983 NPTS (National Personal Transportation Survey)
For the 1983 NPTS, conducted between February 1983 and January 1984, the Census Bureau again collected survey data by using face-to-face interviews in an area probability sample of nearly 6,500 households. In addition to the core NPTS content of travel on travel day, a vehicle inventory, household and person characteristics, information was also obtained about the use of safety devices in household vehicles including seat belts and child safety seats.
Like the previous surveys in the NPTS series, the 1983 survey was conducted using Census Bureau staff and in-person interviews. Given the small sample size dictated by the cost of in-person interviews, and the complexity of the NPTS content, the US DOT sponsors decided to conduct future surveys by phone. This would allow a large group of interviewers to become proficient with the NPTS questionnaire and increased sample size. Like previous surveys in the series, the 1983 NPTS was funded by FHWA, NHTSA, OST, and FTA.
For additional information, see the 1983 NPTS site at FHWA.
1977 NPTS (National Personal Transportation Survey)
For the 1977 NPTS, an update of the 1969 nationwide survey, the data were again collected from households in a national probability sample by Census Bureau staff conducting personal interviews with approximately 18,000 households nationwide. The 1977 survey questionnaires were expanded considerably and updated to better address then-current issues and the survey procedures were modified to upgrade the effort. One of the major differences between the 1969 and the 1977 surveys was the extension of vehicle coverage from automobiles to all motor vehicles owned by the household.
The survey was funded by FHWA, NHTSA, OST, and UMTA (Urban Mass Transportation Administration, now renamed as FTA or Federal Transit Administration.)
For additional information, see the 1977 NPTS site at FHWA.
1969 NPTS (National Personal Transportation Survey)
The original NPTS was conducted in 1969–1970 for the Federal Highway Administration (FHWA) by the U.S. Bureau of the Census. The survey was initiated in response to state highway agencies discontinuing their motor vehicle reports series, which had documented the link between demographics and travel behavior. Funding for the survey was provided by FHWA, NHTSA, OST, and UMTA (Urban Mass Transportation Administration, now renamed FTA or Federal Transit Administration.)
The 1969 survey was based on a multi-state probability sample of housing units located in 235 sample areas representing nationwide coverage. Experienced Census Bureau field staff conducted personal interviews in some 15,000 households, obtaining transportation-related information for all household members. The 1969 survey included collecting data on household automobiles, proximity to public transportation and shopping, travel to work, driver information, travel to school, all one-way trips by POV or public transportation during the previous 24 hours (referred to as the travel day), and all trips lasting one or more nights during the seven days preceding travel day.
For additional information, see the 1969 NPTS site at FHWA.