| Abstract |
In this paper, the Census Transportation Planning Package 2000 (CTPP 2000) for the Delaware Valley region is described, analyzed, and evaluated with special emphasis on the journey-to-work trip data, means of transportation, travel time, employed persons at work, employment, households, vehicle availability, and other data required for transportation planning. The evaluation of Parts 1 and 2 of CTPP 2000 indicated several errors in the data, which were corrected by DVRPC before the data was used in various transportation planning projects. However, data disclosure rules, applied to some tables in Part 3, made the zone-to-zone worker flows by means of transportation totally useless. Except for such tables, CTPP 2000 data is generally accurate and useful for transportation and economic development studies. But, the data should be reviewed and adjusted, if necessary, before they are utilized in transportation planning projects. Based on this evaluation, a set of eight recommendations regarding sample size, nonresponse and imputation, public relations and marketing, place of work coding, processing, data rounding, swapping, and disclosure threshold is proposed. Except for development of a 20 percent sub-sample to improve the accuracy of the responses to the questionnaire, change to rounding rules, and elimination of disclosure threshold, these recommendations are completely consistent with those used by the Census Bureau in Census 2000. Almost all of the CTPP 2000 errors can be avoided if these recommendations are implemented in the future. This is especially important since the overwhelming majority of users cannot review the CTPP data, identify errors, and make appropriate corrections. DVRPC expects the next CTPP to contain accurate data that can be used without any major correction or adjustment. The CTPP is the most efficient and convenient way for obtaining census data to support a wide range of transportation planning studies. |
