SMALL-SAMPLE HOME-INTERVIEW TRAVEL SURVEYS: APPLICATIONS AND SUGGESTED MODIFICATIONS

A method was put forward three years ago for estimating the sample sizes needed for travel surveys from information contained in earlier household surveys. The method showed that very small samples (of the order of 1000-3000 households) could be used to update trip rates and the succeeding steps of travel forecasting by using the information on standard deviations contained in 1950 and 1960 data. Despite the potentially far-reaching impacts of this method, little use appears to have been made of it. An application of the method is described that shows that, in a region of more than 1.6 million households, a sample of 2600 households was estimated as being sufficient to achieve measurement of trip rates to within plus or minus 5 percent sampling error with 90 percent confidence. After the survey had been executed, measured trip-rate variances and sample distribution were compared with those used for sample-size estimation from 1965 data. Although variances and distributions were found to have changed quite substantially, the sample was found to have produced trip-rate estimates that were within or no more than plus or minus 1.5 percent beyond the specified design sampling error. Second, it was found that the method originally put forward does not provide efficient or intuitively appealing samples for the common case of stratified trip-generation relationships. For this case, a procedure is put forward to specify the required levels of error in each stratum in such a way that account is taken of the magnitude of the trip rate and the size of the stratum. It is shown that this procedure is more efficient and that it yields more intuitively appealing sample distributions than the assumption implied by the earlier procedure of an identical percentage error for each stratum.

• Record URL:
  • http://onlinepubs.trb.org/Onlinepubs/trr/1982/886/886-006.pdf
• Summary URL:
  • https://scholar.google.com/scholar_lookup?title=SMALL-SAMPLE+HOME-INTERVIEW+TRAVEL+SURVEYS%3A+APPLICATIONS+AND+SUGGESTED+MODIFICATIONS&author=P.+Stopher&publication_year=1982
• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/isbn/0309034736
• Supplemental Notes:
  • Publication of this paper sponsored by Committee on Transportation Information Systems and Data Requirements. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved.
• Authors:
  • Stopher, Peter R
• Publication Date: 1982

Media Info

• Media Type: Print
• Features: References; Tables;
• Pagination: pp 41-47
• Monograph Title: New concepts in data analysis
• Serial:
  • Transportation Research Record
  • Issue Number: 886
  • Publisher: Transportation Research Board
  • ISSN: 0361-1981

Subject/Index Terms

• TRT Terms: Accuracy; Households; Sampling; Travel surveys
• Subject Areas: Highways; Planning and Forecasting; Public Transportation; Society; I72: Traffic and Transport Planning;

Filing Info

• Accession Number: 00373363
• Record Type: Publication
• ISBN: 0309034736
• Files: TRIS, TRB
• Created Date: Jun 30 1983 12:00AM