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U.S. Department of Transportation
Federal Highway Administration
Bureau of Transportation Statistics
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AASHTO Standing Committee on Planning
In cooperation with the TRB Census Subcommittee

CTPP Status Report

December 2005


American Community Survey (ACS) Update

By Larry McGinn, U.S. Census Bureau

On November 23 the President signed the Census Bureau's 2006 appropriation bill providing the full request of $169.948 million to the American Community Survey. This is the culmination of work since the mid-90's to obtain full funding for the American Community Survey. The Census Bureau will keep the ACS budget flat through 2012 so future budget uncertainty should be minimized.

The next major task is to continue to help all data users understand and best use this new data.


"Workplace Geography" now part of ACS Standard Tabulation Package

by Clara Reschovsky, U.S. Census Bureau

On September 26, 2005, the Census Bureau released tables tabulated at Place of Work as a part of a standard tabulation! Previously, the only standard Census product using workplace geography was the County-to-county flow tabulation (this product can be found at: http://www.census.gov/population/www/cen2000/commuting.html).

Otherwise, workplace tabulations were part of the CTPP, the special tabulation completed from the AASHTO pooled fund.

This release of workplace tabulations was earlier than anticipated due to the impacts of the Hurricanes Katrina and Rita. Data were released for selected areas in AL, AR, FL, GA, LA, MS, TN, and TX. The data is available on the Hurricane Data page on the Census website at: http://www.census.gov/newsroom/emergencies/hurricane_katrina.html.

There are separate tabs across the top of the page for Hurricanes Katrina, Rita, and Wilma. The tables cross Means of Transportation to Work by Sex, Class of Worker, Industry, and Travel Time in four separate tables. You can also access these tables through the American Fact Finder on the Census Website. We anticipate the data for the remaining states will be released in January 2006. In addition to the remaining geographic coverage, 26 additional tables at workplace geography are planned for release in January 2006. For a complete list of Workplace Geography tables, please see: http://www.trbcensus.com/notes/Irvine-Handout_Proposed_ACS_Standard_Tables.xls

On November 18, 2005, the CB released additional 2004 ACS data for the entire nation. The new ACS data release includes a large number of new tables that were not previously available through standard census products. For example, the expanded set includes more than sixty additional transportation tables for residence geography. Since there are far too many tables to list here, I encourage you to check out what is available in American Fact Finder at: http://factfinder.census.gov.

Information for a handful of the new transportation-related tables is shown below.

Selected TransportationRelated Tables Currently Available via American Fact Finder

Table Name
Residence Table Number
WorkplaceTable Number
Sex by Means of Transportation to Work B08006 B08406
Sex by Place of Work - State and County Level B08007 Not Available
Aggregate Travel Time to Work by Sex B08013 Not Available
Means of Transportation to Work by Industry B08126 B08526
Means of Transportation to Work by Class of Worker B08128 B08528
Means of Transportation to Work by Travel Time B08134 B08534
Means of Transportation to Work by Vehicles Available B08141 Not Available

Commentary on ACS table release

By Elaine Murakami

(The opinions expressed here are NOT necessarily opinions of the US DOT)

I, for one, was happy to see the Census Bureau decide to make workplace tabulations a standard product. Because the ACS in 2004 was in a test phase and included approximately one-third of counties in the U.S., it is perhaps best to treat this information as training in familiarity with planned ACS products.

Some things you need to know as you examine these new tables:

Level of geographic reporting: As ACS was still in its demonstration mode with samples in less than 40 percent of the counties each month, 2004 data are currently available only for areas (e.g., States, Counties, Places) with more than 250,000 population. Beginning in late August 2006, tabulations for areas with more than 65,000 population will be available using the 2005 ACS data. In addition to States, Counties, and Places, Public Use Microdata Areas (Census 2000 PUMAs) will also be tabulated. Shape files for PUMAs are available at: http://www.census.gov/acs/www/data_documentation/public_use_microdata_sample/

ACS consistently has less carpooling than Census 2000. In Census 2000 the national carpooling rate was 12.2%. In the 2000 ACS (C2SS) the rate was 11.2%. From Census 2000, Hispanic workers are the most likely to carpool (22% of Hispanic workers reported carpooling, compared to 10% of White, Non-Hispanic workers). Neighborhoods with high Hispanic population have much lower mail-back response rates in ACS than White, Non-Hispanic neighborhoods. Beginning in 2005, the Census Bureau implemented different ratios of non-response follow-up field interviewing, which should capture Hispanic, Black, and Native-American populations more accurately. This may result in differences in means of transportation to work.

ACS is collected over all twelve months of the year. Areas with large seasonal population shifts will see the greatest differences between decennial census data from "April 1" and ACS results.

ACS currently does not include Group Quarters population. Census 2000 includes population in Group Quarters and shows that about 1% of all workers lived in Group Quarters in 2000. In 2000, about 45% of workers who lived in Group Quarters walked to work, accounting for about 16% of the total workers nationwide who walked to work.

The table below shows decennial data from 2000, and ACS data from 2000 and 2004 for Miami-Dade County in Florida. For 2000, the ACS proportion of carpooling is 1 percent lower than that in the decennial census. Using the multi-year profiles from the American Fact Finder, you will find that the ACS carpooling rates of 13.3% in 2000 and 9.4% in 2004 are statistically different at the 90% confidence level. However, the small decline in transit shares is not statistically significant.

Mode to Work, Miami-Dade County, Decennial Census and ACS

Miami-Dade County
Residence
(workers living in area)
Workplace
(workers working in area)
Mode to Work 2000 SF3 ACS 2000 ACS 2004 CTPP 2000 ACS 2004
Total
899,323
978,555
1,007,975
956,460
1,075,227
Drove Alone
73.8%
73.5%
78.4%
74.9%
79.2%
Carpool
14.6%
13.3%
9.4%
14.2%
9.3%
Transit
5.1%
5.9%
4.9%
4.7%
4.7%
Walk
2.2%
3.3%
2.0%
2.0%
1.8%
Other
1.8%
1.5%
1.6%
1.6%
1.6%
Work at Home
2.7%
2.5%
3.6%
2.5%
3.4%

Delays Hit ACS Materials

In previous issues of the "Status Report," we reported on two separate guidebooks that were under development on the use and application of the ACS data. The first, being produced by the Census Bureau, was due in October 2005. While preparing this "Status Report," we learned that the guidebook would be delayed until Spring 2006.

The second guidebook, being developed specifically for the transportation community under NCHRP 8-48 by Cambridge Systematics was due in August 2005. It too has been delayed and NCHRP staff is checking with the contractor. Once a final draft is produced, it must go through a formal review and production process. Hopefully, we will see both guidebooks by Spring 2006.


CTPP User Survey

By Nanda Srinivasan,Cambridge Systematics Inc.

The CTPP User Survey was conducted as a web survey by AASHTO from September 1-15, 2005. Questions included use and satisfaction with CTPP 2000. In addition, users were asked their expectations and concerns as we transition from using decennial Census "Long Form" data to using the ACS data. The survey is available at http://surveys.transportation.org/ctpp.htm

81 staff from various organizations responded to the survey. A majority of the respondents (73 percent) had considerable previous experience (5 or more years of experience) with Census data.

A majority of the users used Census products such as Summary File 1, Summary File 3, and CTPP. Over half the respondents did not use the redistricting file, the Public Use Microdata Sample (PUMS) file, any of the CTPP profiles, or standard Census 2000 publications.

A clear majority of the respondents felt that the biggest problems with CTPP 2000 were late delivery of the data, and rounding and threshold issues which constrain the use of the data. A majority of respondents liked TAZ-UP and the CTPP browser, although several respondents expressed dissatisfaction. Other issues that elicited poorer ratings and complaints included worker counts and workplace geocoding.

Items with the highest satisfaction ratings included CTPP table content, website access, and communications. The CTPP Status Report, Listserve, and technical support by e-mail were also rated highly.

For the future, most survey respondents fully support another CTPP-like product based on ACS. A majority of the respondents say they depend solely on the Census journey-to-work flow for their home-to-work flow matrices. A number of respondents have not yet used any ACS data, and expressed concern about the quality of ACS data.

A summary of the survey findings is posted at http://www.fhwa.dot.gov/planning/census_issues/ctpp/articles/results.cfm

Daytime Population from
Census 2000

By Clara Reschovsky, U.S. Census Bureau

The Census Bureau recently issued "Daytime population" estimates using Census 2000 data (See http://www.census.gov/population/www/socdemo/daytime/daytimepop.html ).

These estimates include:

  1. Workers (as defined in the census and CTPP) no matter where they live, and no matter what time they travel to work.
  2. Residents of an area who are not workers, including everyone who is below 16 years old, and employed people who were temporarily absent from work during the Census reference week.

These numbers can be used to estimate the number of people coming into and going out of a given jurisdiction each day. This calculation provides an Employment-Residence Ratio, which can be used to determine if an area is a bedroom community or an employment center.

Keep in mind that daytime population estimates can be created for tracts using CTPP data. Daytime population in any geography = CTPP Table 1-047 (total population) MINUS first column in CTPP Table 1-001 (total workers living in an the area) PLUS first column in CTPP Table 2-001 (total workers working in the area). Your estimates will be slightly different from Census estimates because of some differences in computation.


TRB Census Data Update

By Ed Christopher, Chair, Committee on Urban Data and Information Systems.

The TRB annual conference will run from Sunday, January 22 through Thursday, January 26, 2006. There are several activities including workshops, papers and posters on the use and application of Census Data products for transportation planning. For a complete list of activities visit the TRB interactive meeting planner and set up your personalized itinerary by visiting http://www.trb.org/am/ip/default.asp?e=68. Once at the meeting planner website, try a keyword search on "census" and you will get a long list of activities, events, papers and poster presentations.

Start your 2006 TRB conference by attending a Sunday workshop on the American Community Survey (ACS). An afternoon workshop (#170) on the ACS will be held from 1:30 to 5:00 p.m. in the Hilton Hotel. The workshop will include presentations on where to get ACS data and how to begin working with it.

The Subcommittee on Census Data for Transportation Planning will meet in the Hilton Hotel, Wednesday between 4:30 and 6:00 PM. Featured at the meeting will be an Evaluation of Census Transportation Planning Package 2000 for the Delaware Valley Region as well as an extensive discussion of issues facing the transportation planning industry.

Sandwiched in the middle are a variety of papers and posters featuring Census data applied in transportation planning. For information on the TRB annual meeting visit the TRB website at http://www.trb.org/meeting/.


AASHTO Standing Committee on Planning (SCOP) Census Data Work Group

By Jonette Kreideweis, MN DOT

The AASHTO SCOP Census Data Work Group held its first conference call in August 2005. Monthly calls have continued to take place. Membership on the Work Group has grown to include individuals from 17 states, as well as representatives from U.S. DOT, FHWA, RITA/BTS, the Census Bureau, APTA, AMPO, NARC and several Metropolitan Planning Organizations (MPOs). To date the group has discussed a number of topics, including:

In addition, the Work Group has begun to identify and discuss topics and issues for future involvement. These focus on three broad themes of Training and Technical Support, Data Use; Applications and Content; and Alternatives for Obtaining Demographic and Work Place Data.

For more information on the Workgroup, please contact Jonette Kreideweis, Minneapolis DOT, jonette.kreideweis@dot.state.mn.us


CTPP Hotline -202-366-5000
ctpp@fhwa.dot.gov

Listserve:
http://www.chrispy.net/mailman/listinfolctpp-news
CTPP Website: http://www.dot.gov/planning/census_issues/ctpp/
TRB Sub-committee on census data: http://www.trbcensus.com
FHWA Website for Census issues: http://www.fhwa.dot.gov/planning/census_issues/
CTPP for 1990 and 2000 downloadable via Transtats: http://transtats.bts.gov/
CTPP Place of Residence Profiles: http://www.transportation.org/ctpp/homeldefault.htrn
Order CTPP 2000 CD-ROM with Software: https://2bts.rita.dot.gov/pdc/index.xml

FHWA
Elaine Murakami
PH: 206-220-4460
FAX: 206-220-7959
Email: elaine.murakami@fhwa.dot.gov
AASHTO
Dave Clawson
PH: 202-624-5807
FAX: 202-624-5806
Email: davidc@aashto.org

Nanda Srinivasan
PH: 202-366-5021
FAX: 202-366-7742
Email: nanda.srinivasan@fhwa.dot.gov

Census Population Division
Phil Salopek
PH: 301-763-2454
FAX: 301-457-2481
Email: phillip.a.salopek@census.gov
Ed Christopher (Urban Data Committee Chair)
PH: 708-283-3534
FAX: 708-283-3501
Email: edc@berwyned.com

Clara Reschovsky
PH: 301-763-2454
FAX: 301-457-2481
Email: clara.a.reschovsky@census.gov

FTA
Eric Pihl
PH: 202-366-6048
FAX: 202-493-2478
Email: eric.pihl@fta.dot.gov
TRB Committees
Ed Christopher (Urban Data Committee Chair)
See under FHWA
RITA/BTS
Pheny Smith
PH: 202-366-2817
FAX: 202-366-3370
Email: pheny.smith@bts.dot.gov
Bob Sicko (Census Subcommittee Chair)
Mirai Associates
PH : 425-820-0100
FAX: 425-821-1750
E-mail: bob@miraiassociates.com

CTPP Listserve

The CTPP Listserve serves as a web-forum for posting questions, and sharing information on Census data. Currently, over 700 users are subscribed to the listserve.

To subscribe, please register by filling a form posted at:
http://www.chrispy.net/mailman/listinfo/ctpp-news

On the form, you can indicate if you want e-mails to be batched in a daily digest. The website also includes an archive of past e-mails posted to the listserv.

For questions on the listserve, please e-mail Ed Christopher at edc@berwyned.com.

Updated: 04/02/2014
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