Why is there no data on zone-to-zone (and superdistrict-to-superdistrict) bicycle and walk commuters from Census 2000?
Data on detailed means of transportation for all workers (e.g., bicycle, walk, ferryboat, railroad, etc.) is from CTPP 2000 Table 3-6. This particular table is subject to the 3 sample minimum threshold, which has a serious data suppression impact at the zone-to-zone and tract-to-tract geographic levels. For example, the county-to-county commute file for intra-Bay Area shows 35,722 bicycle commuters, but the tract-to-tract commute file, intra-Bay Area, shows only 27,298 bicycle commuters, a data loss of 23.6 percent. Similarly, the county-to-county intra-regional walk commuters is 104,454, whereas the tract-to-tract intra-regional walk commuters is 87,318, a data loss of 16.4 percent. There is no obvious method to “impute” or make up the missing data.
