CTPP 2000 Status Report

CTPP Contract between AASHTO and Census Bureau Delayed

Census Bureau's DRB Has Not Approved Proposed Tables

The Census Bureau's Disclosure Review Board (DRB), which has approved the CTPP residence-only and workplace-only tables with rounding for the CTPP, has yet to approve the proposed worker flow tabulations. After its initial review of the proposed tables in August 2001, the DRB approved the publication of the worker flow tabulations subject to the geographic reporting restriction that each flow combination has a minimum threshold of 50 unweighted records. As this restriction would eliminate nearly all TAZ-to-TAZ reporting in the CTPP, and in some cases, would prevent county-to-county tabulations, AASHTO, the USDOT, and the Census Bureau are negotiating what tables will be included in the worker flow tabulation (home-to-work). The list of proposed tables is presented below.

CTPP 2000: Revised List of Part 3 (Worker Flow) Tables for Small Geography

As the negotiations stand, the DRB has recommended that two tables, Table 3-1 (Total Workers) and Table 3-2 (Total Workers by Mode to Work--17 categories) be released without a minimum threshold. Tables 3-8 through 3-14 that present aggregate statistics, e.g. means, medians, aggregates, also could be released without a minimum threshold. However, Tables 3-3 through 3-7 would ONLY be released subject to a minimum threshold of 3 un-weighted records in the geographic flow pair e.g. TAZ-TAZ. In addition, all flow tables would be rounded.

Because the DRB has not made it clear what evaluative criteria it used for this determination, the CTPP Working Group is continuing its negotiations to determine if there are any other acceptable alternatives for obtaining flow tables without thresholds. The Working Group has submitted another query to the DRB and awaits their response. The DRB's next meeting is scheduled for January 14, 2002.

Who/What is the DRB?

The DRB is comprised of Census Bureau staff who have the responsibility to ensure that individuals cannot be identified through published Census Bureau products.

In response to the DRB's initial determination that called for the minimum threshold of 50 unweighted records, Dr. Sen wrote to Mr. Barron explaining that by limiting the release of information to this minimum threshold would make this data set essentially useless for transportation planning. Administrators Jennifer Dorn (FTA) and Mary Peters (FHWA) also sent a letter conveying their support of Dr. Sen's letter. In response, a sub-group of the DRB was assigned to meet with the CTPP Working Group.

On the basis of the discussions with the DRB Subgroup, the CTPP Working Group submitted a revised set of tables that favor simple 1-way tabulations for counts, but also includes 2-way tables for summary measures (means, aggregates). The revised list, although considerably less comprehensive than the original CTPP 2000 request, includes tables that were not available in the 1990 CTPP.

Rounding is acceptable

The DRB is requiring that all special tabulations from the decennial census use rounded values. Specifically for the CTPP, values between 1 and 7 would be rounded to "4", and values 8 and over would be rounded to the nearest "5". After examining 1990 CTPP data which was not rounded, rounding it and comparing the results of rounded and unrounded data, most members of the CTPP Working Group believe that rounded values will have little impact on the utility of the CTPP 2000 dataset.

Some Important Websites:

CTPP Website:

http://www.fhwa/dot.gov/ctpp

^NEW FHWA Census Issues Website:

This new Website contains all issues relating to the decennial census that are of interest to the transportation planning community.

http://www.fhwa.dot.gov/planning/census/

^NEW TRB Census Data Subcommittee: The website address has now changed to:

http://www.trbcensus.com

^NEW Census 2000 Supplementary Survey:

http://www.census.gov/acs/www/SBasics/SSizes/SSizes2.htm

American Community Survey(ACS):

http://www.census.gov/acs/www/

Are You *Still* Subscribed to the CTPP Listserve?

In the last few months, we have noticed several "list-serve bound" e-mails bounce back to us because of wrong e-mail addresses. If you have not received any

e-mail from the CTPP listserve community in the past few weeks, chances are that you are no longer subscribed.

To subscribe, please send an e-mail to majordomo@chrispy.net with "subscribe ctpp-news" as the body of your message OR send an e-mail to edc@trbcensus.com.

Nanda Srinivasan is in the process of contacting all MPOs to update the CTPP agency database. If the contact information for your agency has changed, please send an e-mail to nanda.srinivasan@fhwa.dot.gov.

Census 2000 Supplementary Survey: An Update

By Nanda Srinivasan, Cambridge Systematics Inc.

The American Community Survey's Census 2000 Supplementary Survey (C2SS) was a sample survey of 700,000 households conducted in 1,203 counties. Data was collected throughout the year 2000. In mid-August, the Census Bureau released C2SS data for states and the nation. In mid-November 2001, data for counties and places with populations over 250,000 were released. Like the decennial census, the C2SS provides information on three key elements of commuting activity: ownership of personal vehicles; travel mode to work, and travel time to work. While C2SS data exhibit some methodological differences from the decennial data, it can be used for comparison for most purposes until the decennial data are available. The first long form data from the decennial census

TRB Subcommittee: Message from the Chair

At this time of year it is always instructive to take a quick glance back, but more importantly, set a focus for the future.

The year 2001 began quietly enough with our American Community Survey (ACS) proposal winding its way through the National Cooperative Highway Research Program process. While the project was not selected for funding in 2001-2002, it did make it to a contingency list, and was resubmitted through the 2002-2003 process. This time through, the Subcommittee secured support not only from the TRB data committees but also the AASHTO Standing Committee on Planning. With this added support we are optimistic that the project will make it through the selection process. A summary of the proposal can be found at http://www.TRBcensus.com/notes/nchrp_acs.html

This past August the Internet service provider where the Subcommittee's web pages were housed went "belly-up". As a result, a domain name was secured and a new site launched. The new web address is http://www.TRBcensus.com/. In addition to this location the CTPP Working Group within the US Department of Transportation (DOT) managed to secure a first level directory web address under the USDOT main page. The USDOT CTPP web address is http://www.dot.gov/ctpp/. With two Web sites we should see an even greater abundance of materials being posted. The intent of the two web sites is to allow CTPP specific materials to gravitate towards the USDOT maintained pages while the Subcommittee can broaden its sights to include other census data that is important to the transportation planning community.

Now that Census 2000 is complete, there are two things worth keeping an eye on. The first are the reports people will prepare, examining the quality and methodological issues surrounding the census. The second area to watch for is the "cool" and "exciting" things people are doing with the data.

On the methodological front, the U.S. General Accounting Office in December 2001 released a report analyzing the costs for conducting the Census 2000. The study found, among other things, that the estimated full-cycle cost of the 2000 decennial census of about $6.5 billion was nearly double the $3.3 billion reported full-cycle cost of the 1990 decennial census. For a complete copy of the 27-page report go to http://www.gao.gov/new.items/d0231.pdf

The other things to look for are the new and innovative "stuff" that people are doing with the Census data. If you think back a short 10 years to our last decennial census you can see some very noticeable changes that have occurred. In 1991, many of us were still sharing computers and the idea of a PC on your desk with spreadsheet, mapping and statistical capabilities was only a dream. The ability to do online data searchers with services like the Census Bureau's American Fact Finder (http://factfinder.census.gov/home/saff/main.html?_lang=en) and those offered by just about every major newspaper in the country was also a dream. The USA Today still has a good site to check http://www.usatoday.com/news/census/index.htm. In short, as our resource and computing ability have become more sophisticated, so have our products.

Other issues to keep a watchful eye on during the year include: the development of the CTPP especially as it relates to the Census Bureau's Disclosure Review Board process and restrictions; the establishment of statewide TAZs; the definition of the areas that the urban CTPP components will cover; the new Census Urbanized Area boundaries (due out in March); and a series of outreach materials--a brochure and video to be released in early 2002 followed by an instructional electronic guidebook.

As these issues and many more unfold we need to hear from you. Many times members of the subcommittee and CTPP Working Group are called on for our collective opinions. One source for that information is the CTPP-News listserve. You can post to the listserve at ctppnews@chrispy.net. To be added to the listserve just drop me an email at edc@TRBcensus.com.

So, let's hear from you!

Ed Christopher,
Chair, TRB Sub-committee on Census Data for Transportation Planning

CTPP Hotline - 202-366-5000

FHWA

Elaine Murakami
PH: 202-366-6971 (206-220-4460 in Seattle)
FAX: 202-366-7660
Email: elaine.murakami@fhwa.dot.gov

Nanda Srinivasan
PH: 202-366-5021
FAX: 202-366-7742

Email: nanda.srinivasan@fhwa.dot.gov

Ed Christopher (Census Subcommittee Chair)
PH: 708-283-3534
FAX: 708-283-3501
Email: edc@berwyned.com

Lynn Weidman
PH: 202-366-7245
FAX: 202-366-3640
Email: lynn.weiiedman@bts.dot.gov

FTA

Eric Pihl
PH: 202-366-6048
FAX: 202-493-2478
Email: eric.pihl@fta.dot.gov

Sarah Clements
PH: 202-366-4967
FAX: 202-493-2478
Email: sarah.clements@fta.dot.gov

AASHTO

Dave Clawson
PH: 202-624-5839
FAX: 202-624-5806
Email: davidc@aashto.org

Census Bureau Geography Division

Carrie Saunders
PH : 301-457-1099
FAX : 301-457-4710
E-mail: carrie.g.saunders@census.gov

Census Population Division

Phil Salopek
PH: 301-457-2454
Fax: 301-457-2481
Email: phillip.a.salopek@census.gov

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

TRB Committees

Ed Christopher (Census Subcommittee Chair)
See under FHWA

Chuck Purvis (Urban Data Committee Chair)
PH: 510-464-7731
FAX: 510-464-7848