Incoming query to CTPP: 1. The Size of TAZ : In your TAZ-UP manual(4-6) we have been told that "there are no minimum size criteria for TAZs for CTPP 2000 . ... however, that census data may be suppressed to protect confidentiality if a TAZ is too small." What do you mean "too small"? Could your give us a number (or a range) of RESIDENTS and WORKERS refers to this definition? You provided us 1990 historical mean number/range for RESIDENTS and WORKERS per TAZ. It seems that we have great flexibility to set our own criteria for defining the size of TAZs for CTPP 2000. To avoid possible problems caused by this ambiguity, we prefer to have a clear criteria number or range from you. Do you have any suggestion for us to dealing with those TAZs that have mixed land use? Another words, if a TAZ has both RESIDENTS and WORKERS in it, should we use RESIDENTS or WORKERS to define our TAZs? ----------------- Response from Elaine Murakami, FHWA