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Policy and Governmental Affairs
Office of Highway Policy Information

FHWA Home / Policy & Governmental Affairs / Highway Policy Information / Traffic Volume Trends / Office of Highway Policy Information

Travel Monitoring

Frequently Asked Questions

  1. What does TVT mean?
  2. What information does TVT have?
  3. When is the monthly TVT report published?
  4. Can you notify me when a new TVT report is posted on your website?
  5. What data are used by the FHWA to produce the TVT?
  6. When should State highway agencies submit their CCS data to FHWA?
  7. How does the FHWA handle missing State data in the TVT production?
  8. What is TMAS and how do I get access to it?
  9. How many CCS and short duration (portable) traffic counting sites should a State have?
  10. How is TVT produced each month?
  11. What are seasonally-adjusted vehicle miles traveled (VMT)?
  12. How can I use the seasonally-adjusted VMT data?
  13. What is the process used to gain the seasonally-adjusted VMT?
  14. What are the QA checks applied to CCS traffic data submitted by State agencies?

  1. What does TVT mean?

    TVT is the abbreviation for Traffic Volume Trends which is a monthly report on nationwide vehicle miles traveled (VMT). The Travel Monitoring and Surveys Division of the Office of Highway Policy Information within the Federal Highway Administration (FHWA) develops and publishes the report.

  2. What information does TVT have?

    TVT reports the VMT on all U.S. public roads monthly. This includes the national total VMT by roadway functional classes, area types (rural/urban), states and regions, percent changes of VMT compared to the same month of the prior year, individual monthly total VMT, year-to-date and moving 12-month cumulative totals, and seasonally adjusted national monthly total VMT.

  3. When is the monthly TVT report published?

    The TVT report is produced and released within 60 days after a month’s closing. You can get a copy of the report by visiting the web link at https://www.fhwa.dot.gov/ohim/tvtw/tvtpage.cfm.

  4. Can you notify me when a new TVT report is posted on your website?

    Yes. You need to sign up at https://www.fhwa.dot.gov/policyinformation/travel_monitoring/tvt.cfm. Click on the eSubscribe button that is near the top right corner of the webpage.

  5. What data are used by the FHWA to produce the TVT?

    Two datasets are used to produce the TVT. The first one is the Highway Performance Monitoring System (HPMS) data (submitted to the FHWA yearly by State highway agencies). This dataset is used to calculate the base year VMT. The second is data submitted by State agencies via the Traffic Monitoring Analysis System (TMAS) (collected through Continuous Count Stations (CCS) by State highway agencies). This dataset is used to compute percentages of growth or decline from the base year VMT.

  6. When should State highway agencies submit their CCS data to FHWA?

    Monthly traffic data collected by CCS should be submitted to the FHWA within 20 days after a month’s closing. For example, the January 2023 data should be submitted to the FHWA no later than February 20, 2023.

  7. How does the FHWA handle missing State data in the TVT production?

    In the event that a State does not have complete monthly CCS data (e.g., CCS data for a given roadway functional class is missing), the TVT procedure is to estimate the missing value(s) based on the average VMT of other roadway functional classes within the State. If the State does not have any valid values, the average value from the surrounding States for the same roadway functional class is used. If no data from surrounding State/States are available, National averages for the same roadway functional class are used.

  8. What is TMAS and how do I get access to it?

    TMAS stands for Travel Monitoring Analysis System. TMAS provides online data-submitting capabilities to enable State traffic offices to upload their CCS data to FHWA. Access to TMAS is obtained through the FHWA Division office in each State. This link provides contact information for all the Division offices: https://www.fhwa.dot.gov/field.html#fieldsites.

  9. How many CCS and short duration (portable) traffic counting sites should a State have?

    At a minimum, a State should have 6 CCS sites for each group of roadway functional class and rural/urban area type combination (7 classes x 2 area types x 6 sites per unique class & area type = 84 sites total). For detailed information, please visit the Traffic Monitoring Guide at https://www.fhwa.dot.gov/ohim/tmguide/index.htm and the Highway Performance Monitoring System (HPMS) Chapter 6 at https://www.fhwa.dot.gov/policyinformation/hpms/fieldmanual/ . For definitions of roadway functional classification, Please visit https://www.fhwa.dot.gov/planning/processes/statewide/related/highway_functional_classifications/

  10. How is TVT produced each month?

    VMT data in each month’s TVT report are based on two data sources:

    • The Highway Performance Monitoring System (HPMS), and
    • Monthly traffic counts from continuous count stations (CCS).

    The HPMS compiles data from the states annually concerning the condition and performance of all roads in the United States. HPMS includes the annual average daily traffic (AADT) by road segment. When these AADTs are multiplied by the length of their corresponding road segments and then summed, this yields the total VMT. The VMT for a particular road segment are treated as the base year VMT and will be used in the TVT Report along with the monthly CCS data.

    States submit CCS traffic counts monthly. There are about 5,500 CCS stations used to collect data that is reported to the FHWA each month.

    CCS data are submitted and processed using the Travel Monitoring Analysis System (TMAS). The FHWA runs quality control (QC) checks on all data received. Only data that passes the QC checks are used for the TVT report.

    For each state, the monthly average daily traffic (MADT) for each CCS station is computed based on the CCS data. Each CCS based MADT is compared to its corresponding MADT of the same month of the previous year to yield a change rate. If the change rate passes the QA checks, it is then used to compute the functional class based average monthly changes.

    TVT estimates monthly VMT by combining the change rates for each month with the most recent base VMT from HPMS. The TVT report is available to the public within 60 days after the close of the month. Data that covers a minimum of 40 states and 70% of the VMT is required for publication. The next month's TVT report will include an update for states that resubmitted or updated their CCS data.

    The December TVT provides the first estimate of annual VMT. This annual VMT is preliminary. When the annual HPMS data become available, they will supersede the TVT VMT as the benchmark VMT.

  11. What are seasonally-adjusted vehicle miles traveled (VMT)?

    Seasonally adjusted VMT are monthly VMT adjusted to eliminate day of week, weekday and weekend, number days of a month, and holiday effects. Monthly shifts in data as well as short and long-term trends can be best seen through seasonally-adjusted data.

  12. How can I use the seasonally-adjusted VMT data?

    Seasonally-adjusted VMT data enables comparisons with any other month in any other year. Analysis of seasonally-adjusted VMT is an alternative to unadjusted VMT, which traditionally uses comparisons of a month to the same month in previous years to determine trends. Seasonally adjusted VMT data enables not only the same monthly travel pattern comparisons from different years, but comparisons with any other month.

  13. What is the process used to gain the seasonally-adjusted VMT?

    Seasonal adjustment is a process of estimating and removing movement in a time series caused by regular seasonal variations in activity, e.g., an increase in VMT during summer months or when a major holiday like Thanksgiving occurs at the end of a month with travel spilling-over into December. The Bureau of Transportation Statistics, U.S. DOT uses Census X13-ARIMA Seasonal Adjustment Program to seasonally adjust VMT. For more information on seasonal adjustment, please visit the Bureau of Transportation Statistics weblink at https://cms7.bts.dot.gov/archive/subject-areas/economics_and_finance/deseasonalized_data/seasonally-adjusted-vehicle-miles-traveled/documentation/seasonally_adjusting_vehicle_miles_traveled

  14. What are the QA checks applied to the CCS traffic data submitted by State agencies?

    Specific QA criteria are applied to all CCS traffic data submitted by State agencies before the data are used for VMT production. These criteria include:

    • The number of consecutive zeroed hourly volumes cannot be more than the site specified threshold
    • Any hourly volume cannot be over the site specified threshold if it is proceeded by a zero hourly volume
    • Any hourly volume cannot be over the site specified maximum value
    • Any site must contain data of at least 7 days of any month in any travel direction
    • Site specified thresholds can be different by region and state.
Page last modified on January 27, 2023
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