to see first hand how the taz/tad development software works
DESCRIPTION
Why are we here Today?. To see first hand how the TAZ/TAD development software works. Introduction to CTPP TAZs and TADs. What is CTPP TAZs and TADs Things to think about Resources. What is the CTPP?. Census Transportation Planning Products (CTPP) Program - PowerPoint PPT PresentationTRANSCRIPT
To see first hand how the TAZ/TAD
development software works
Why are we here Today?
Introduction to CTPP TAZs and TADs
What is CTPP
TAZs and TADs
Things to think about
Resources
What is the CTPP?
Census Transportation PlanningProducts (CTPP) Program
The CTPP is an umbrella program of Census related data products, custom tabulations, training, technical assistance, and research for the transportation community
Designed and paid for by transportation planners for transportation planners
Why are Custom Tabulations so important?
Summarize data by Place of Residence Place of Work Flows between Home and Work
Unique Universes (e.g. workers in HHs)
Custom Geography (Local TAZs)
Traffic Analysis Zones - defined by the local transportation data user for the local transportation data user
Sometime in 2013 New Product is due out
New
Geography
NO data will be suppressed
XXXXXXXXX Sometime in 2013
What is a TAZ/TAD?
● Custom Geography for CTPP data tabulations
●Defined by MPOs and State DOTS
● Developed in Spring/ Summer 2011
● Funded under CTPP Program
● GIS equivalency process built from Census Blocks
TAZTraffic Analysis
Zone
Traditional Size
TADTraffic Analysis
District
20,000 population
What is an equivalency process?
Take the map at the right and using the states boundaries make 9 contiguous regions
It’s the same for TAZsBlocks
cluster into TAZs
TAZs/TADs Building Blocks
● 2010 Census Blocks will make up TAZs
● TAZs will make up TADs
● TADs can cross Counties and States
● TADs can be built from TAZs, Block Groups or Tracts
http://www.fhwa.dot.gov/ctpp/acsdataprod.htm
Nov/Dec 2010 - Agencies verified contact names Feb 2011 - Web-based training (2-25 and 2-28)
March through April 2011 - Online delivery of software and Census 2010 data and geographic files (Rolling basis)
3- Months to delineate TAZ/TADs
June through July 2011 - Files returned to CB Geography
TAZs/TADs Inserted into TIGER data base
The Schedule
2010 TIGER files http://www.census.gov/geo/www/tiger/tgrshp2010/tgrshp2010.html
TAZ Size
CB recommends~600 persons
corresponds to the minimumthreshold for 2010 Census Block Groups
Threshold is guideline not a requirement
TAZs may be defined with fewer than 600 residents or workers
Data reliability and availability improves as population size increases
Bigger is Better
Why the hang-up on TAZ size
Big Zones make happy data
● ACS is a small sample
● Smaller areas have lager MOES
● Statistical Collapsing
● Confidentiality and Disclosure rules
Important concept to follow
When is a TAZ Not a TAZ?
When it is a C-TAZ
Important Concept
TAZs and TADS for Census ACS data do not have to be the same as the TAZs used in your travel forecasting models
Think of these as Census TAZs or (CTAZs) Census TADs or (CTADs)
Travel Forecasting Zones as
Planning Zones or Planning Units
Large Zones are Better for ACS Data
Hmmm
TAZs
TAZs
Why are TADs so important?
● Higher quality data
● Less chance for disclosure proofing
● More real data
● Potential 3-year data coverage w/No Swiss Cheese
NE Illinois (2009 3-year ACS)
5-year Geography and Flows
● Asymmetrical Flows
● Small Areas defined by MPOs in MPO areas and States Elsewhere
● Tracts are Defaults for Small Areas
● Default TADs under discussion
TADs as CBDs, Special Districts, etc
16
The Software
Using the Census Bureau MAF/TIGER Partnership Software
Census Bureau Contract (CTPP Paying for it)
Caliper is the contractor
Calling it the MTPS TAZ Element formally TAZ-UP
Download materials, software and files from Census Bureau site.
Some TAZs resource materials
http://www.fsutmsonline.net/images/uploads/mtf-files/PPT_12_TAZ%20White%20Paper_NOV07_FINAL_CS_Keli_Wu.ppt
http://www.fsutmsonline.net/images/uploads/reports/FDOT_TAZ_White_Paper.pdf
Florida Standard Urban Transportation Model Structure
White Paper on Recommended Approach to Delineating TAZ
http://www.census.gov/geo/www/psap2010/psap2010_main.html
Important sizes / More on PSAP
How many Block Groups can be contained in a single Tract?http://www.census.gov/geo/www/psap2010/bg_criteria.txt
Thank You
Ed ChristopherFHWA Resource Center
4749 Lincoln Mall Drive, Room 600Matteson, IL 60443