Transcript The American Community Survey

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
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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
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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
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ACS Data Release Schedule
Data products are released in the year following the single year
or multiyear period in which data are collected.
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Information about the American
Community Survey
www.census.gov/acs/
Subscribe to the
ACS Alert
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Means of Transportation
on 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
Bus or trolley bus
Streetcar or trolley car
Subway or elevated
Railroad
Ferryboat
Taxicab
Motorcycle
Bicycle
Walked
Worked at home
Other method
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Other Commuting Information
on 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
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Journey-to-Work ACS Data Products
Data products and prefixes
B
C
S
R
GCT
M
Base Detailed Table
Collapsed Detailed Table
Subject Table
Ranking Table (single-year only)
Geographic Comparison Table
Thematic Map
Commuting products are numbered “08”
Example: B08xxx is a Base Table on commuting
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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)
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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
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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)
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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
(single year data only)
(R08xx)
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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
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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
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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
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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 in 3
categories: bus, streetcar and subway, railroad and ferry)
Travel time
Time leaving home
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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
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U. S. Census Bureau
Melissa Chiu, CTPP Coordinator
Journey-to-Work & Migration Statistics Branch
Housing and Household Economic Statistics
301-763-2421, -2454
[email protected]
www.census.gov/population/www/socdemo/journey.html
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Orientation to American Factfinder
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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
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Data Products- American FactFinder
factfinder.census.gov
Select Dataset and Product Type
Organized by
dataset then by
data product
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List all Tables- Select “08” Products
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Select Geography
Many ways to select geography
Geography is hierarchical:
First select type of geography,
then specific area.
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Subject Table- Example (S08xx)
Click “Data Sets” to
change data product
Print, download, save
or load a query
Change
year,
geography,
subject
table
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Detailed Table- Example (B08xxx/C08xxx)
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)
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Detailed Tables- Geo Components
(down to state only)
Download to get all
geographies
and tables at once
Click Next to see other
geographies selected
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Download- Example
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Ranking Table- Example (single year only)
Can sort by rank or by state
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Geographic Comparison Table- Example
(GCT08xx)
Geographies or geo components
within nation or state only
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Thematic Map- Example (M08xx)
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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
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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
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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
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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
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Data Download Center- Example
On American FactFinder …
Data Sets page on upper right
…or left side bar
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Data Download Center- Example
Select Dataset
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Data Download Center- Example
Select one
geographic
level
Select data product type
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Data Download Center- Example
Select up to 50 tables and ‘Add’
Click ‘Next’ to get to
‘Start Download’ then
download a .zip file
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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: |
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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
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