Improving Accuracy in Household and External Travel Surveys

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D.F. Pearson, E.N. Hard, S.P. Farnsworth, T.L. Forrest, D.L. Spillane, M.I. Ojah, K.N. Womack, S.A. Boxill, C.A. Lewis

Publication Date:

January 2010


The Texas Department of Transportation has a comprehensive on-going travel survey program. This research examines areas within two select travel surveys concerning quality control issues involved in data collection and sampling error in the data caused by various assumptions, survey methods, and issues such as non-response. Quality control issues, sampling errors, and non-response in external and household travel surveys conducted in Texas are identified, examined, and evaluated. The impact of these issues is quantified and evaluated relative to the use of the data in travel demand models. The state-of-the-practice in these types of surveys relative to quality control during and after the surveys are conducted and how sampling errors and non-response are treated (or corrected) in the survey analysis are reviewed and documented. The results are assessed to formulate a set of recommendations for incorporating into survey designs for the travel survey program.

Report Number:



External Survey, Household Survey, Response Rates, Survey Methodology, Geocoding, Data Analysis, Vehicle Classification Counts, Sample Size, Survey Design

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