The purpose of the project was to develop estimates of average weekday household person trips, vehicle trips, person miles traveled, and vehicle miles traveled (per day), for all Census tracts in the United States.
The Bureau of Transportation Statistics (BTS) developed a model that allows for Census tract estimation using the National Household Travel Survey (NHTS) data along with American Community Survey (ACS) data from the Census Bureau. The model divides the NHTS data into six geographic areas, classifies these areas as urban/suburban/rural, and then estimates average weekday household: person miles traveled, person trips, vehicle miles traveled, and vehicle trips for each geographic area. The BTS model then transfers the estimates to individual Census tracts using the household and demographic data from the ACS for each Census tract.
The resulting Census tract estimates provide beneficial indicators to local governments and other customers who may not have the budget and/or time for conducting their own local survey. Additionally, the use of a standard set of questions across all geographies in the NHTS enables comparison across geographies that otherwise would be captured in separate local surveys with potentially different methodologies.
A small number of census tracts do not contain estimates for a variety of reasons, such as census tracts with zero population, or census tracts with very unusual demographic or travel characteristics.