What is a Traffic Analysis Zone (TAZ)?
• TAZs are the units of the geographic boundary system used by the PSRC to run and report results from its Travel Demand Forecast Model. The TAZs nest within a larger Forecast Analysis Zone (FAZ) geographic boundary system, with each FAZ containing between 1 and 20 TAZs. TAZ boundaries generally, with few exceptions, also line up with census tract boundaries, with each census tract containing between 1 to 9 TAZs. There are a total of 938 TAZs in the region. What is a Census Tract? • What is a Census Block Group? • A block group (BG) is a cluster of census blocks within a census tract that have the same first digit of the four-digit block identifying number. For example, block group 3 (BG 3) within a census tract includes all blocks numbered from 3000 to 3999. Block groups generally contain between 600 and 3,000 people, with an optimum size of 1,500 people. A census tract can contain between 1 to 9 block groups. • What is a Census Block? • Census blocks are the smallest unit within the
