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The National Household Travel Survey. Heather Contrino US Department of Transportation Federal Highway Administration Office of Highway Policy Information. Outline of Today’s Presentation. About the NHTS Methods and Data Data Applications NHTS Products and Tools. About the NHTS.
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The National Household Travel Survey Heather Contrino US Department of Transportation Federal Highway Administration Office of Highway Policy Information
Outline of Today’s Presentation • About the NHTS • Methods and Data • Data Applications • NHTS Products and Tools
About the NHTS… • Only national data source on travel demand and travel behavior of the American public. • Measures travel by US households for all modes and all purposes • Survey conducted since 1969
The NHTS obtains information on the public’s use of the transportation system Highway Statistics, 2001
The NHTS Program – Two Components • National Study • Serves the department, congress, and administration • Sample size of 25,000 households • Add-On Program • Allows States and MPOs to purchase additional samples for their local area • Program participation has doubled every survey year (Sample size of 125,000 households for 2008)
NHTS Program Structure NHTS Program Add-On Program n = 125,000 List Assisted RDD Some Additional Questions National Study n = 25,000 List Assisted RDD Cell Only n = 1,250 National coverage
2008 Add-On Program Participants 125,000 Add-On Samples Vermont DOT Wisconsin DOT South Dakota DOT New York State DOT Cedar Rapids, IA Iowa DOT Indiana DOT Omaha, Nebraska California DOT Virginia DOT North Carolina DOT Tennessee DOT Piedmont Region Maricopa, AZ South Carolina DOT Pima, AZ Georgia DOT Texas DOT Florida DOT
NHTS Add-On Program Benefits What We Get • Leadership in household travel survey data • Larger program, visibility, stakeholders and users • Greater analysis power What They Get • Administrative Functions (program management, contracting, and quality assurance) • Comparability • Legitimacy • Partnership
NHTS Program Features • Adding questions – each Add-On allowed five additional questions • Sample plan – area specific sample plans (within the constraints of overall sample methodology) • Quality Assurance – On-line access to status reports and monthly progress reports to Add-Ons
Study Design • National list assisted RDD with CATI • Population of interest - US Households with telephones • Advance letter with incentives • Multi-stage design Travel Data Retrieval Diary Mailing Advance Letter Household Recruitment
Study Design (continued) • Single day travel period for all household members age 5+ • All trips by all modes of travel, including walk and bike and access and egress modes • NHTS covers all days of the year with day of week and month of year balance
Study Design - New for 2008 • Minimum State samples (n=250) • Cell Phone only sample • Add-On specific questionnaire content • New data items for national study • Improvements in weighting and adjustments
NHTS Core Data Content Major Contribution Linkage between people, travel and vehicles • Households • Income, composition, location • Persons • Age, sex, race, ethnicity, worker and student status, citizenship, education • Geography • High level geography – urban, rural, suburban, state and national analyses • Vehicles • Make, model, year, mileage, alternative fuels, commercially licensed • Trips • Mode, time of day, purpose, vehicle occupancy, distance, trip length
New 2008 NHTS Content • Congestion • Interstate use and tolling • Telecommuting – opportunity and frequency • Work arrival time and flexibility • Safety • Safe Travel to School • Travel impacts of disability • Energy and Environment • Shopping by Internet and deliveries to the household • Hybrid/Alternative fuel vehicles • Fuel costs by vehicle type and travel behavior • Vehicle age, odometer reading, and annual mileage • Alternative Modes • Access (to transit) travel party size • Frequency of walk and bike • Motorcycle ownership and use
Trend Data - There has been amazing growth in travel since 1969Growth in Travel and Related Issues, 1969 - 2001 Base: NHTS series since 1969
Travel Demand – But in the last decade, total trips have leveled off… Base: NHTS data series, travelers 16+
Commute Fam/Pers (inc. Shop) School/Ch Soc/Rec 14,000 12,000 10,000 8,000 Person Trips in Millions 6,000 4,000 2,000 0 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 4 5 6 7 8 9 10 11 Start Hour Congestion - Non-work Travel Adds to Peak Period Congestion
Mobility and impacts on access and travel options This is the daily range of travel for a high income African American This is the daily range of travel for a low-income African American
NHTS is used to develop daytime populations for security research… Number of workers at work, visitors, people in motion and people at home 2:00 pm Tuesday Memphis, TN Source: 2001 NHTS, Nate Erlbaum, NY DOT
And for special studies… (example Florida DOT) • Hurricane Evacuation Planning • Weekend and Holiday Travel Planning • Seasonal Resident Impact Broward County, Florida Source: ACS 1999-2002, U.S. Census Bureau
Changes in population growth effect transportation demand Estimated on current VMT/person from NHTS and Census population forecast
Men Women All 600 500 400 300 200 Annual Miles in Billions 100 0 2000 2010 2020 2030 2040 The driving population is aging…Projections show a doubling of VMT by 2040 for drivers aged 65 and over Base:Census projections and VMT/person from NHTS 2001
Which has safety implications as older drivers are more likely to be in a fatal accident… Base: NHTS data on driver miles by age and FARS fatalities
Which are used for Safety Planning… Pedestrian Fatalities per Mile of Exposure Source: 2001 FARS pedestrian Fatalities and NHTS 2001 miles walked
And to help understand the link between transportation and health: Is increased vehicle use related to reduced walking and biking? VMT Per Driver Mode Share to Walk/Bike Source: Matt Coogan
Transit planners can use NHTS to understand who uses transit…
And how transit is used:(not just commuting) Percent of Transit Trips by Purpose
‘What if’ scenarios for climate change: Source: McGuckin’s analysis based on NHTS 2001
And cold and hot starts for air quality analysis: Vehicle Starts, Trip Lengths by Time of Day and Vehicle Utilization Source: 2001 NHTS, Nate Erlbaum, NY DOT
Which allows us a unique perspective on the economics of travel:
2008 NHTS Schedule • Data collection completed – April 2009 • Final weighted data file – October 2009 • Public Use file – January 2010 • Methods Research (for next NHTS) and work for reauthorization is ongoing
Future Design Goals • Methods • Coverage and Response Rates • Cellular phones and non-contacts • Periodicity • Real time reporting environment • Continuous study design/annual reporting • Relevant Content • Establishing regular, reliable performance measures • Maintaining trends while addressing new policy and planning questions
NHTS Program Goals • Institutionalize the Study • Specific program authorization and regular funding cycle • Maintain Add-On Program • Regular State and MPO participation – federal, local and community gains • Serve User Community • Clear link to policy and planning questions • National and State travel indicators • On-line Analyses • Annual reporting of Key Measures • Modeling and data integration to provide annual estimates • Annual/continuous data collection • Feed into performance measurement, annual reporting to Congress (C&P), and other data programs (e.g. FARS)
NHTS Products • State Profiles • Policy Briefs • Trends Database • Transferability • On-line Analysis Tool • Risk Assessment Tool • AAA Traffic Safety Foundation NHTS Trends CD-ROM