Accuracy of Travel Pattern Estimates from the Home Interview Survey (167-8)

This report presents the results of a study of the accuracy of home interview survey data in estimating zonal travel patterns. The study is primarily based on 100 percent survey data collected by the Texas Highway Department in three apparently homogeneous adjacent zones in San Antonio. The general data analysis demonstrates the general conformance of observed travel characteristics with expected characteristics from urban travel theory. The 100 percent data were used as a data base from which sets of repeated random samples were drawn at various sampling rates. Comparison of the results from the sets of random samples with the actual population data demonstrates the levels of accuracy which may be expected in estimating zonal interactions, interchange volumes, and trip length frequency data. In addition, the entire San Antonio home view survey was used as the data base to determine the sample size needed to adequately estimate the mean trip length for the urban area.