The 1977 NPTS was the second Nationwide Personal Transportation Survey, conducted by the Bureau of the Census under the sponsorship of the Department of Transportation. The purpose of the 1977 NPTS was to address the full range of trips and travel in the United States, along with the related social and economic characteristics of the tripmaker.
The 1977 NPTS was designed to collect information on all trips taken during a designated 24-hour period and some additional detail on trips, as well as trips of 75 miles-or-more during the preceding 14-day period. The 1977 NPTS collected information on the use and availability of public transportation facilities, types of motorized vehicle available to the household, characteristics of the trips taken, including mode, purpose, miles traveled, time required and persons on the trip. The additional information obtained for trips of 75 miles-or-more included stops during the trip and uses of additional modes of transportation. One of the most unique features of the 1977 NPTS was the attempt to estimate the amount of travel in urban and rural areas by the use of mapping during the home interview.
The 1977 NPTS was based on a nationwide sample of 24,466 households. Of the 24,466 households, 3,433 units were found to be vacant, demolished, converted to nonresidential use, or otherwise ineligible for the survey. Some 3,084 households were not interviewed because the occupants were not at home after repeated calls, refused to participate in the survey, or were unavailable for some other reason.
The NPTS was conducted as part of the expanded scope of the National Travel Program of the Bureau of the Census. The NTS/NPTS included a common sample of 13,365 households (referred to as the basic sample) interviewed from April-November 1977 and January 1978; and were interviewed four times for NTS and once for NPTS data. An additional 4,584 addresses (referred to as the supplemental sample) were divided into three equal parts and were interviewed in December 1977, as well as February and March 1978. This spread the total NPTS data collections over a 12-month period from April 1977 - March 1978, with approximately 1500 households interviewed each month.
Interviewing was accomplished primarily by a personal visit with the household. A letter informing each household of the 1977 Survey was sent prior to the visit. Interviewers were instructed to contact the household the day following the travel day to complete the household interview; if this was not possible all interviews for the household were to be completed within 4 days of the travel day to minimize recall problems. All household members, 14 years of age-and-older were interviewed only once and asked to report all trips taken during a 24-hours period, as well as trips of 75-miles-and-longer during the 14-day period immediately preceding the travel day. A knowledgeable adult household member was asked to report all trips (excluding bicycling and walking trips) taken by household members between the ages of 5-13 years.
Data collection was conducted by the Census Bureau's field staff, located in 12 Regional offices throughout the United States. Interviewers were selected from the current surveys interviewing staff.
Each staff member was trained prior to beginning work on the survey, including three days of classroom training plus self-training materials. Additional home study materials and classroom training were planned throughout the interviewing period. Formal training was supplemented by on-the-job training sufficient to insure job performance at the level of established standards. Quality control measures, such as editing returns, observing interviews and reinterviewing selected sample households were employed throughout the survey.
The major steps performed by the Bureau of the Census for the 1977 NPTS included clerical editing and coding of the NTS-2 Questionnaire, (Sections I-VI); the NTS-2A (Section VII) was edited and coded by FHWA staff. A full Transcription of the data to magnetic tapes; computer edit of the data to ensure completeness and consistency; calculation of the weighting factors for each household; and computation of variance and calculation of statistical reliability of the data was performed as well. The FHWA tabulated the data upon receipt of the edited, weighted data tapes from the Bureau of the Census.
Last updated January 28, 1999