VT Census Case Studies : National Household Travel Survey

Created and last modified by molfe on 02 Jan 2016

Brief Overall Description of the Dataset:

The National Household Travel Survey (NHTS) provides information to assist transportation planners and others who need comprehensive data on travel and transportation patterns in the United States. The NHTS dataset contains data for all 150,147 completed households in the sample including household, person, vehicle and daily (travel day) trip level data. Data is collected on daily trips taken in a 24-hour period, and includes: purpose of the trip; means of transportation used; how long the trip took; 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, driver characteristics; and vehicle attributes. 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.

Link:   http://nhts.ornl.gov/

Date Inventory Completed: 6/18/2015

Screening

  • Is the data collected opinion-based?
  • Is the data collection recurring (must be collected at least annually)?
  • Is there data available for 2013?
  • Is the data collected at the property or housing unit level?
  • Can we access the data by August 15th?

Purpose

  • What is the purpose of the organization collecting the data?

U.S. Department of Transportation Federal Highway Administration  oversee federal funds used for constructing and maintaining the National Highway System, provides highway design and construction services for various federal land-management agencies, performs and sponsors research on transportation and infrastructure.

  • Why is it collected and how does the organization use it?

The NHTS and the predecessor survey, the NPTS (Nationwide Personal Travel Survey), serve as the nation’s inventory of daily travel. 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.

  • Who else uses the data?

The transportation research community, including academics, consultants and government

  • Who do they sell the data to?

Free

 

Method

  • What is the data collection method? 

The NHTS was conducted as a telephone survey, using ComputerAssisted Telephone Interviewing (CATI) technology. All household members in households who completed a household recruitment interview were sent diaries for their travel day. Of the over 300,000 household members who completed person interviews, 72 percent reported having filled out the travel diary.

  • What is the type of data collected? 

Designed

  • If designed, who created the questions?

NHTS researchers

  • What is the raw source of the collected data (prior to any aggregation)? 


Description

  • What is the general topic of the data (1-2 words)?

Transportation

  • What are the earliest and latest dates for which data is available?

The current data come from the2009 NHTS, which updates information gathered in the 2001 NHTS and prior Nationwide Personal Transportation Surveys (NPTS) conducted in 1969, 1977, 1983, 1990, and 1995.

  • Is data collected and available periodically?

No

  • How soon after a reference period ends can a data source be prepared and provided? 

Not stated


Selectivity

  • What is the universe (e.g., population) that the data represents?

The NHTS is a survey of the civilian, non-institutionalized population of the United States.


Accessibility

  • How is the data accessed? 

Downloaded in csv format

  • Is it open data?

Yes

  • Any legal, regulatory, or administrative restrictions on accessing the data source?

None stated

  • Cost? - One time or annual or project based payment?

Free

Does this dataset appear to meet our needs for the Census study? No

Full Inventory

Description

  • Features
    • What is the temporal nature of the data: longitudinal, time-series, or one time point?

One point in time

    • Geospatial? If Yes, at what level?

Census division and state


Metadata

  • Is there information available to assess the transparency and soundness of the methods to gather the data for our purposes?

Yes

  • Is there a description of each variable in the source along with their valid values?

Yes

  • Are there unique IDs for unique elements that can be used for linking data?

No

  • Is there a data dictionary or codebook?

Codebook:  http://nhts.ornl.gov/2009/pub/Codebook.pdf

Data dictionary: http://nhts.ornl.gov/2009/pub/DataDictionaryPU.xls

 

Selectivity

  • What unit is represented at the record level of the data source?

Household

  • Does this universe match the stated intentions for the data collection? If not, what has been included or excluded and why?

An eligible household for the sample excludes telephones in motels, hotels, group quarters, such as nursing homes, prisons, barracks, convents or monasteries and any living quarters with 10 or more unrelated roommates.

  • What is the sampling technique used (if applicable)? 

150,147 households in the landline sample. Designed as a list-assisted random digit dialing survey, to yield an equal probability sample of households with landline telephones

  • What was the coverage?

The NHTS is a survey of the civilian, non-institutionalized population of the United States. As such, an eligible household excludes telephones in motels, hotels, group quarters, such as nursing homes, prisons, barracks, convents or monasteries and any living quarters with 10 or more unrelated roommates. All trips reported by eligible household members in eligible households in the U.S. were recorded.


Stability/Coherence

  • Were there any changes to the universe of data being captured (including geographical areas covered) and if so what were they?

20 Add-on partners who are state and metropolitan transportation planning organizations that fund additional samples to use as a household travel survey for their respective jurisdictions. The weighting factors have been adjusted to account for the oversampling in the Add-on areas.

  • Were there any changes in the data capture method and if so what were they? 

Recent use of digital survey

  • Were there any changes in the sources of data and if so what were they? 

None Stated

 

Accuracy

  • Any known sources of error?

There are many sources of error in addition to error occurring because only a sample was selected. Some examples of nonsampling include:  A respondent misunderstands a question and answers it incorrectly,  A respondent does not recall a trip or remembers details of the trip incorrectly,  An interviewer does not correctly record what the respondent says,  A person or household is a nonrespondent, and  A person does not answer a specific question. Undercoverage may also be a source of error. Undercoverage occurs for several reasons, including that a household has no telephone, a person states incorrectly that the telephone number we have dialed is not residential, and the household respondent either accidentally or purposely does not report all the people living in the household.

  • Describe any quality control checks performed by the data’s owner.

Interviewer monitoring: In order to ensure that the data were complete and of high quality, a series of data editing procedures were implemented. During the review of edits and cleaning of responses for travel day trips, it was sometimes necessary to slightly modify a response or impute a missing response for the resolution of incorrectly completed items.

See: http://nhts.ornl.gov/2009/pub/UsersGuideV2.pdf

 

Accessibility

  • Any records or fields collected, but not included in data source, such as for confidentiality reasons)? 

None stated

  • Is there a subset of variables and/or data that is must be obtained through a separate process? If yes, is there a separate legal, regulatory, or administrative restrictions on accessing the data source? Cost? - One time or annual or project based payment?

No

 

Privacy and security

  • Was consent given by participant? If so, how was consent given?

None stated (but in person survey so could be verbal consent)

  • Are there legal limitations or restrictions on the use of the data? 

None stated

  • What confidentiality policies does the source have? 

None stated

 

Research

  • What research has been done with this dataset? (e.g., impact of policies, predictors of student success)

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.

  • Include any links to research if provided:

http://nhts.ornl.gov/publications.shtml

  • List any other data use notes provided by the supplier.

 

Gaps/Concerns

  • Feasibility - can all jurisdiction levels provide the data (if applicable)?
  • Data ownership - a lack of clarity in legal guidance stemming from a lack of clarity with who owns digital data?
  • Data collection authority - what data is reasonably private and what constitutes unwarranted intrusion?
  • Describe any other notes you have or any gaps/concerns you see with this dataset: