TAZ/TAD delineation program overview

Overview Traffic Analysis Zone (TAZ) and Traffic Analysis District (TAD) delineation criteria and guidelines –Why define them? What are they? –Criteria and guidelines –How the criteria and guidelines are built into rules and checks in the MTPS High level process/flow of the TAZ delineation program Schedule 2

TAZs and TADs Why define them? What are they? Traffic Analysis Zones (TAZs): –a basic spatial unit of analysis representing an area containing similar kinds of land use and commuter travel –5-year CTPP data Traffic Analysis Districts: –aggregates of similar TAZs –3-year CTPP data 3

Criteria & Guidelines 4 TAZTADNotes Aggregates of…2010 census blocks2010 TAZs OverlapTAZs may not overlap (one TAZ assigned/ block) TADs may not overlap (one TAD assigned / TAZ) Nest within & cover the entire area of… CountiesState DOT/ MPO coverage State DOT and MPO coverage is one or more complete counties. TADs may cross county boundaries. CodesUnique within county Unique within State DOT/ MPO coverage TAZ and TAD codes are up to 8 characters, alphanumeric, and padded with leading zeros Minimum thresholds Resident or worker* population > 600 suggested Resident or worker* population > 20,000 Data reliability and availability improves as resident and worker population increases * 2000 block-level worker estimates were interpolated to 2010 block boundaries.

Criteria & Guidelines 5 TAZTADNotes Aggregates of…2010 census blocks2010 TAZs

Criteria & Guidelines 6 TAZTADNotes Aggregates of… OverlapTAZs may not overlap (one TAZ assigned/ block) TADs may not overlap (one TAD assigned / TAZ) Interactively, one can only assign an area to one TAZ or one TAD. Adding an area assigned to an existing TAZ or TAD to a different TAZ or TAD will remove it from the original TAZ/TAD.

Criteria & Guidelines 7 TAZTADNotes Aggregates of.. Overlap Nest within & cover the entire area of… CountiesState DOT/ MPO coverage State DOT and MPO coverage is one or more complete counties. TADs may cross county boundaries. Nest within: TAZ delineation - will not allow you to select geography in two different counties when creating or editing a TAZ TAD delineation – will not allow you to delineate TADs outside the county coverage (in setup file) Cover area of:

Criteria & Guidelines 8 TAZTADNotes Aggregates of… Overlap Nests within … CodesUnique within county Unique within State DOT/ MPO coverage TAZ and TAD codes are up to 8 characters, alphanumeric, and padded with leading zeros

Criteria & Guidelines 9 TAZTADNotes Aggregates of… Overlap Nests within … Codes Minimum thresholds Resident or worker* population > 600 (suggested) Resident or worker* population > 20,000 Data reliability and availability improves as resident and worker population increases * 2000 block-level worker estimates were interpolated to 2010 block boundaries.

Additional checks 10 Contiguity Compactness

High level TAZ/TAD delineation process/flow 11 2 Receive from GEO TAZ team with customized setup file, and instructions to call for MTPS download username/password. Mid-March through April 3 Open setup file and confirm correct county coverage in “CoreCountyCoverage” 4 Call GEO TAZ Team for MTPS download username/password 5 Download the MTPS software, partnership shapefiles (counties specified in setup files), and user documentation from Census Bureau’s website, save to local drive 6 Save setup file to the same local drive folder as the partnership shapefiles (e.g., “TAZlayers”) 1 Check the AASHTO website spreadsheets to confirm expected county coverage for 2010 TAZ/TAD delineation. Let us know ASAP if not what you expect.

High Level TAZ/TAD delineation process/flow (2) 12 4 Run setup for the MTPS, and Delineate TAZs and TADs a Choose startup methods for TAZs and/or TADs - TAZs: 2000 TAZs, 2010 tracts, 2010 block groups, scratch, BEFs - TADs (no TAZs): 2010 tracts, 2010 block groups - TADs (with TAZs): scratch and BEFs b Delineate TAZs e Run TAD verification checks d Delineate TADs c Run TAZ verification checks f “Report Changes” (i.e., create output files) Can divide work among multiple staff members prior to delineation (by editing the setup file (for dividing work on complete counties or administratively assigning county – parts)

High Level TAZ/TAD delineation process/flow (3) 13 5 FTP output files to Census Bureau, follow up with Within 90 days from receipt of setup file mid-June to early-July 6 Census Bureau will run verification checks on submissions, and will contact program participant with any problems or issues that do not have clear fixes

TAZ/TAD Delineation Timeline February 25 & 28: Web-based TAZ delineation software training March – April: Delineation materials available starting in March June – July: Delineation submission returned to Census Bureau within 90 days of delineation material availability (i.e., receipt of setup file ) 14

Questions? GEO TAZ team: