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Public Transportation Data in the American Community Survey (ACS) and Census Transportation Planning Products (CTPP). Dec 3, 2009 AASHTO Standing Committee on Public Transportation and Multi-State Technical Assistance Program Winter Meeting Melissa Chiu, CTPP Coordinator
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Public Transportation Data in the American Community Survey (ACS) and Census Transportation Planning Products (CTPP) Dec 3, 2009 AASHTO Standing Committee on Public Transportation and Multi-State Technical Assistance Program Winter Meeting Melissa Chiu, CTPP Coordinator Journey-to-Work and Migration Statistics Branch Housing and Household Economic Statistics Division U.S. Census Bureau
Transition to the American Community Survey • The 2010 Census will not ask journey-to-work information • Census “long form” information is now asked on the American Community Survey (ACS) Large, continuous demographic survey Produces characteristics, not a population count Produces annually updated single-year and multi-year estimates of the characteristics of the population and housing Produces information for small areas including tracts, block groups and population subgroups - updated every year
How Does the Sample Compare? • Timing ACS samples every year and spreads sample over 12 months Census samples once a decade and uses the entire sample at the same time • Follow-up ACS subsamples for personal visit follow-up Court ruled against census subsampling • Sample size ACS 5-year estimates based on about 11 million housing units Census sample estimates based on about 18 million housing units
ACS Data Release Schedule Data products are released in the year following the single year or multiyear period in which data are collected.
www.census.gov/acs/ Subscribe to the ACS Alert Information about the American Community Survey
Means of Transportationon the ACS Questionnaire • Same as on Census 2000 long form • Q: How did this person usually get to work last week? Car, truck, or van Motorcycle Bus or trolley bus Bicycle Streetcar or trolley car Walked Subway or elevated Worked at home Railroad Other method Ferryboat Taxicab
Other Commuting Informationon the ACS Questionnaire • Ridership for car, truck or van Report up to 99 people Census 2000: reporting topcoded at 7 or more • Time left home to go to work Hour and minute, time of day • Usual travel time to commute Report up to 999 minutes • Place of work Report street address, zip code Geocoded to block, if possible
Journey-to-Work ACS Data Products • Data products and prefixes B Base Detailed Table C Collapsed Detailed Table S Subject Table R Ranking Table (single-year only) GCT Geographic Comparison Table M Thematic Map • Commuting products are numbered “08” Example: B08xxx is a Base Table on commuting
Journey-to-Work ACS Data Products • Detailed tables show univariate and crosstab frequencies and some summary statistics • Detailed table examples (B08xxx / C08xxx): Means of transportation by worker characteristics Travel time by time leaving home Place of work for metropolitan, micropolitan, and non-metro/micro levels Vehicles available in household • Majority of tables available at both residence geography (B081xx, B082xx, B083xx) & workplace geography (B084xx, B085xx, B086xx)
Journey-to-Work ACS Data Products • Detail in means of transportation varies by table All 5 public transportation categories shown on univariate table and sex crosstab 3 categories (bus, streetcar and subway, railroad and ferry) shown on travel time crosstab A single public transportation category shown on all other crosstabs of means of transportation
Journey-to-Work ACS Data Products • Subject Tables based on same information as Detailed Tables but more user friendly format • Tables show distribution and summary of characteristics • Examples (S08xx): Commuting characteristics by sex (S0801) Characteristics by means of transportation to work (Public transportation grouped together) - at residence geography (S0802) - at workplace geography (S0804)
Journey-to-Work ACS Data Products • Ranking Tables, Geographic Comparison Tables, and Thematic Maps all show data on five measures of commuting: Mean travel time to work (#01) Percent of workers who traveled to work … by car, truck, or van alone (#02) by carpool (#03) by public transportation (#04) Percent of workers who worked outside county of residence (#05) • Residence geography only • Ranking Tables rank states (R08xx) (single year data only)
Journey-to-Work ACS Data Products • Geographic Comparison Tables allow comparison of more geographies on the same measures • Examples (GCT08xx): Mean travel time to work for all counties Percent of workers who traveled to work by public transportation for all places (cities) Percent of workers who worked outside county of residence by urban / rural, metropolitan and micropolitan area status
Journey-to-Work ACS Data Products • Thematic Maps allow users to design maps on the same measures (M08xx) • Levels of geography available: State County Metropolitan/ micropolitan statistical area Congressional district Public Use Microdata Area (PUMA) Combined Statistical Area • Can determine… Data classes: number and breaks Boundaries and features
The Census Transportation Planning Products (CTPP) • Special tabulation of commuting data Used Decennial Censuses since 1960 Plans for using American Community Survey data (2006-2008) and (2006-2010) • Schedule 2006-2008 3-year CTPP planned for release summer 2010 TAZ Delineation program in spring/summer 2011 2006-2010 5-year CTPP currently planned for summer 2012 release
CTPP Table Structure • Part 1 Residence Geography • Part 2 Workplace Geography • Part 3 Home-to-Work Flows • Tables include … • characteristics of workers & households Vehicles available in household Income • characteristics of trips Means of transportation (Public transportation mostly in3categories: bus, streetcar and subway, railroad and ferry) Travel time Time leaving home
CTPP Resources • Federal Highway Administration (FHWA) www.dot.gov/ctpp Upcoming CTPP data products 2000, 1990 CTPP data products • Bureau of Transportation Statistics (BTS) CTPP 2000, CTPP 1990 data download www.transtats.bts.gov • Transportation Research Board trbcensus.com • AASHTO ctpp.transportation.org
U. S. Census Bureau • Melissa Chiu, CTPP Coordinator • Journey-to-Work & Migration Statistics Branch • Housing and Household Economic Statistics • 301-763-2421, -2454 • melissa.c.chiu@census.gov • www.census.gov/population/www/socdemo/journey.html
Organization of ACS Data in the American FactFinder (AFF) • 1. Datasets (ACS, Census) • 2. Data year(s) • 3-year data products are the default • 1-year and 3-year data products distinguished • 3. Data products • 4. Specific tables or maps • Assistance links highlighted
factfinder.census.gov Data Products- American FactFinder
Organized by dataset then by data product Select Dataset and Product Type
Many ways to select geography Geography is hierarchical: First select type of geography, then specific area. Select Geography
Click “Data Sets” to change data product Print, download, save or load a query Change year, geography, subject table Subject Table- Example (S08xx)
Select geo type, e.g. urban, rural, metro, principal city Change to collapsed version Can select multiple areas for detailed tables Can select multiple detailed tables too (scroll down) Detailed Table- Example (B08xxx/C08xxx)
Download to get all geographies and tables at once Click Next to see other geographies selected Detailed Tables- Geo Components(down to state only)
Can sort by rank or by state Ranking Table- Example (single year only)
Geographies or geo components within nation or state only Geographic Comparison Table- Example (GCT08xx)
Thematic Map- Options • Statistical significance view Select a geography Displays all areas that are statistically significantly different from the selected geography Can save as .PDF file under “download” menu
Other Options in American Factfinder • Can create “Custom table” from the detailed tables • Data Download Center • Download selected ACS tables for all available geographies at one time • Can “Download PUMS data” file for microdata
Data Download Center • Download large amounts of ACS data • Geographic units • Total U.S. • States • Counties • Places • CBSAs (Metro and Micro Areas) • Congressional Districts • All areas meeting minimum population threshold
Data Download Center • ACS Tables (Selected) • Base / Detailed tables • Data profiles • Subject tables • Choose up to 50 tables at one time • Download .zip file consisting of .txt files • README file • Geographic identifiers • Data- estimate and 90% MOE for each cell, all tables • Files pipe-delimited [ | ], can load in Excel
On American FactFinder … Data Sets page on upper right …or left side bar Data Download Center- Example
Select Dataset Data Download Center- Example
Select one geographic level Select data product type Data Download Center- Example
Select up to 50 tables and ‘Add’ Click ‘Next’ to get to ‘Start Download’ then download a .zip file Data Download Center- Example
.Zip file includes a readme file on data values, geographic identifiers, and data file(s) Open data file in Excel as ‘Delimited’ by pipe: | Data Download Center- Example
Supplementary Data Options • Integrated Public Use Microdata Series (IPUMS) • usa.ipums.org/usa • Census microdata, historical • National Historical Geographic Information System (NHGIS) • www.nhgis.org • Aggregate census data, historical • Boundary files, historical