Most of you are working hard to complete your TAZ definitions to be submitted to the Census Bureau Geography Division.
Why are they due on October 1, 1999?
One of the goals of the CTPP Working Group is to get the CTPP 2000
data delivered earlier than in previous decades. Defining TAZs
now will improve our chances of getting the CTPP data delivered to
us by late 2002 or early 2003. TAZs will be added to the tabulation
geography of the individual records rather than in a post-processing step
using equivalencies between census blocks and TAZs, as was done in
1990.
The Census Bureau will enter the TAZ geography into the central TIGER database between October ‘99 and Jan ‘00. They will issue TIGER/Line 99 in early 2000 for the TAZ verification phase. TIGER/Line 99 will include TAZs that you have submitted as well as (near final) 2000 Census tract boundaries. You will have an short window (about one month) of opportunity to review your TAZs and make corrections to submit to the Census Bureau.
Is October 1 the real deadline?
No, October 1 is the “official” deadline. However, the Census
Bureau Geography Division recognizes that errors in some of the TIGER files
caused delays in delivering some of the TIGER/Line 98 files to you for
the TAZ-UP program. However, if you cannot meet the October 1 deadline,
you MUST send an email to ctpp@fhwa.dot.gov
on or before October 1, and let us know that you still plan to submit TAZs
but will be late. You must submit your TAZs by October 29, 1999.
How do I submit my TAZs?
The instructions for submittal are on page 9 of the “Reference” section
of the TAZ-UP manual. If you are not using TAZ-UP, you should have
received paper instructions on the file format and submittal instructions.
If you have questions, please send an email to ctpp@fhwa.dot.gov,
or call 1-202-366-5021, to ask Nanda Srinivasan for assistance. If
you have difficulty with the electronic file submission to the Census Bureau,
please call Valerie Murdock at 301-457-1099.
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Visit our Frequently Ask Questions at Call our CTPP HotLine at 202-366-2000 or Email us ctpp@fhwa.dot.gov
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The Local Review of Employer Files (LREF) program that described in previous CTPP Status Reports has undergone a name change. This project is now being called the Workplace Update (Work-UP). The new name still relays the overall nature of the project and highlights the similarities with the TAZ update project that is currently underway. Both programs involve the use of an extension to ArcView GIS with the TIGER/Line 98 files and local updating.
Under the Work-UP project, MPOs will use an extension to ArcView GIS
to evaluate the commercial employer database Census licensed for their
area. The extension will include the following capabilities:
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Management |
1) Sort the file by ZIP code, street name, type of business, number of employees, or census geography (such as tracts or block groups). |
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Own Employer File to TIGER'98 |
2) Select and work on only those records the Census Bureau was not able to geocode. |
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Employers |
3) Add employer names and addresses to the file. |
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Names and Employer Addresses and Re-geocode |
4) Correct the names and addresses of employers, re-geocoding the address
against the TIGER/Line 98 file and placing a new point on the map. If the new address cannot be geocoded, the user will be able to assign the employer record to a point by clicking on the employer's location on the map. |
Any changes or deletions made by the MPO will be written to a transaction file which will be returned to Population Division at Census. The verified employer list will be used in place-of-work block coding after the 2000 Census. The automated phase of the coding will use both the address and the employer name information provided by the respondents and choose the best match. For responses that fail automated (machine) coding, Census Bureau clerks will attempt to geocode them using both the address and employer name information. Thus the quality and completeness of the employer database will directly affect the quality of the place-of-work data released in the CTPP 2000.
Progress implementing the Workplace Update project has been slow, and as a result the schedule has slipped. The process to contract with a vendor to produce an ArcView extension is finally well underway at Census and should be completed this month. Shipment of the employer files and Work-UP extension to the MPO’s will probably not occur until late November or early December. This will constrict the amount of time MPO’s have to review the file to four months, instead of the six months we were hoping for. Once the contract is in place for the development of the Work-UP extension, the Census will contact the MPOs by mail to find out who is interested in participating in the program. In the meantime, questions can be referred to Clara Reschovsky or Phil Salopek in the Journey-to-Work and Migration Branch at (202) 366-5000, option #4, or (301) 457-2454.
Invited session on CTPP tables held
On June 25th, the Bureau of Transportation Statistics hosted a working
group to discuss the standard set of tabulations to be produced for the
CTPP 2000. Attendees came from different sectors of the transportation
planning field including large MPOs, small MPOs, state DOTs, transit agencies,
and private consultants. The highest priority expressed by
the group was the wish for custom tables on demand. Paul Reim from the
Central Transportation Planning Staff (CTPS, the MPO for Boston) summed
up the general sense of things as, “Keep everything and give us more!”
Standard CTPP
First, the group agreed that the traditional CTPP package of standard
tabulations should be produced. One basic requirement for the CTPP
is to maintain compatibility between the 2000 and the 1990 packages. It
will cover all the basic tables, especially those which have typically
been used in the 4-step travel forecasting models, while adding new tables
to meet the transportation planning needs associated the Americans with
Disabilities Act, Environmental Justice, and Welfare-to-Work. Some
examples include the number of vehicles available in a household by race;
poverty status by mode to work; and, the travel time to work by earnings.
The group also recommended that standard deviation on the means for variables such as travel time should be added to the package. As the final tables are drafted the CTPP Planning Group will share the list with the transportation planning community for review and comment.
Tables on Demand
The attendees used many of the tables in the 1990 CTPP, but they sometimes
needed tables that were not part of the package. There were two methods
to meet these demands. First, contract with the Census Bureau for
a special, individual tabulation, and second, to use another source such
as the Census Public Use Microdata Sample (PUMS). A system for tabs-on-demand
could greatly reduce the need for these two alternatives. It could
provide a faster way to obtain custom defined tables and reduces the programming
time and money needed to produce standard tabs.
At the Census Bureau, a tabs-on-demand program is being developed and called the American Fact Finder. It is online at http://www.census.gov. This system will provide the Census 2000 data across a variety of subject areas summarized at their home or residential location.
A critical question concerns the role that American Fact Finder can play in fulfilling the transportation planning needs. The key difference between standard census tables and the CTPP has been the use of the workplace geography as a summary level. The CTPP 2000 Planning Group is grappling with the practical issues of how to provide tabs-on-demand and at the same time address disclosure and geographical concerns. Another issue is whether or not the American Fact Finder can be augmented to accommodate the transportation planning needs or should a separate query system be developed.
Summary
Given the concerns of the invited group of CTPP data users, two separate
paths will be pursued. CTPP 2000 will include many of the same tables
as the 1990 CTPP for Statewide Elements Parts A, B and C and the Urban
Elements Parts 1, 2, and 3. The CTPP Planning Group will work diligently
to develop a tabs-on-demand system which meets both the needs of the transportation
community as well as the Census Bureau's needs regarding confidentiality.
The CTPP Planning Group is striving for the overall goals of speedier delivery,
better employer geocoding, improved delivery mechanisms and high quality
data.
The CTPP 2000 data in combination with other regional surveys can be very beneficial to transportation planners. Transit operators, Metropolitan Planning Organizations (MPOs) and State Department of Transportation should be deciding what other data should be collected in conjunction with, or in close proximity to the decennial census. This will ensure supplemental data collection efforts, surveys, and studies that support the usefulness of CTPP 2000 are collected to parallel census data.
At the regional level, the CTPP is well suited to the task of estimating and validating trip distribution and modal choice models for journey-to-work. However, journey-to-work data from the CTPP may be too coarse for detailed route-level transit planning or fine-tuning an existing service. Census data can be supplemented by on-board ridership surveys, on-off counts, and other sources to carry out finer analyses. Surveys done in conjunction with the decennial census are important because the Journey to Work question in the Census addresses only one mode, and not multiple modes. For example, if a person drives to a park and ride, and then rides a bus or a rail, it is not reflected in the data. Secondly, the issue of trip chaining is not addressed, and we know that many workers make stops on their way to work, e.g. to drop off a child.
The transit operations planners are responsible for efficiently tailoring the supply of transit service to meet anticipated or actual demand. Primarily, the transit operations planner has two major objectives; to maximize service effectiveness and its efficiency. Census data supplemented by other auxiliary data can help in addressing these objectives by providing information on travel characteristics and socioeconomic characteristics. CTPP provides data on residence to work flows. The data such as population, age of residents, number of physically handicapped people, income levels, vehicle ownership etc., can help in efficiently addressing transit operation issues. The CTPP can provide data to understand ridership markets. MPOs and transit operators should consider surveys independent of the decennial census to augment the CTPP data. For example, the Delaware Valley Regional Planning Commission (DVRPC) has developed a number of transportation surveys (planned over several years) to supplement CTPP 2000 data. A few of these surveys include:
Regina Armstrong of Urbanomics presented a paper entitled “Economic and Social Relevance of Central Cities in the Nation’s 12 Largest Urban Regions” as part of the TRB conference on “Transportation Issues in Large U.S. Cities” held in Detroit, Michigan in June, 1998. This article is summarized from that paper.
The original intention of the Census Transportation Planning Project was to assist transportation planners with their models. However, its uses have expanded to include other areas of study, particularly economics and economic development. This paper examines the twelve largest metropolitan regions in the U.S., using the CTPP to look at the distribution of employment in comparison with residential population.
Armstrong points out that large urban areas are the most diverse in terms of socio-economic characteristics such as race and ethnicity, nativity, language spoken, educational attainment, household formation, household mobility, and labor force participation. While the population of these areas looks different from the rest of the country, that population takes one third of all work trips, on just 3 percent of the land area of the U.S. The density of these regions separates them from the rest of the country.
One single factor that makes large urban areas different from other areas is immigration. Most immigrants to the U.S. settle in a large city, which affects languages, education, household make-up, labor force participation and demand for employment. This is a trend that will continue to influence the conditions of large urban areas well into the next century.
Of jobs in the U.S., other than agriculture and self-employment, about 34 percent are located in the 12 largest urban regions. However this employment represents about 45 percent of the gross domestic product (GDP). The difference is due to higher productivity and profitability of many employers in large urban areas. Most jobs in the major central cities are white-collar jobs that require higher educational attainment than many city residents can provide. “Whereas the 14 central cities had a net shortfall of 2.9 million workers for their job locations, the suburbs had a surplus of 3.5 million workers.” (p. 133). As a result, there is a significant discrepancy between city residents and city jobs. Clearly an important result of this discrepancy is commuting between cities and suburbs and in recent years between suburbs. Often workers are not compatible with the jobs near their home. The CTPP can help to identify these mismatches allowing planners to try and alleviate the problems.
Another part of the economic conditions of central cities, urban regions, and the rest of the country that needs to be considered by transportation planners is the proportion of expenditures by the federal government on each of those regions. Looking at large urban regions as a whole, their proportion of federal funds is about proportionate to their populations, but not their earning capacity. Narrowing in on central cities, that proportion is larger. However, it is in line with the cities’ portion of the GDP. The CTPP can provide data on worker characteristics at the work end to figure out the economic ramifications of worker earnings with their residential locations.
While the CTPP cannot answer all of the economic questions facing planners in large urban regions, it is a unique source of data about workers characteristics and residential choices that can help transportation planners and economic developers to increase the vitality and coordination of these regions as a whole.
The Conference Proceedings are published in Transportation Issues in Large Cities, Conference Proceedings 18" TRB. Contact TRB at 202-334-3214, email: TRBsales@nas.edu for a copy of the proceedings.
By now everyone should be almost finished defining their TAZs and have
turned them into the Census Bureau for review. For those individuals
with TAZ questions, check the "Frequently Asked Questions" posted on the
subcommittee's
Website at: http://www.TRBcensus.com/notes/tazfaq.html.
Looking back on June 27th and 28th, the Data Committees of TRB met for their mid-year meeting in Washington DC. At the meetings the Subcommittee made the record books by hosting the first ever webcasted session in TRB history. The speakers at the session, entitled "The Reality of the American Community Survey for Transportation" raised many of the questions that are facing the transportation planning community as it looks towards the changes brought on by a continuous survey methodology.
The webcast, which was lead by Committee on Information Systems and Technology, allowed remote users to log onto the Internet and hear the presentations and see the session material without the need to travel to Washington. Oscar Franzese, from the Center for Transportation Analysis at the Oak Ridge National Laboratory, developed the webcast. It is currently available on-line at http://www-cta.ornl.gov. To listen and view it, users will need the correct media players. "How to" information is also available from the Oak Ridge web page. Questions about the webcast can be directed to Oscar at ofz@ornl.gov or 423-576-8682.
Looking ahead, Census issues will be discussed at two different sessions during the TRB annual meetings in January. The first discussion will be part of a larger data session that will address the overall 2000 Census. The second session, sponsored by the subcommittee, will focus exclusively on the details of CTPP 2000. At this session we will hear a discussion of what will happen next with regard to TAZs, see a demonstration of the Workplace Update Software (Work-UP) previously known as LREF, and discuss the table content and distribution mechanisms for the final CTPP. The TRB annual meetings will be in Washington D.C. from January 9th through the 13, 2000.
Ed Christopher
Chair, TRB Subcommittee on Census for Transportation
Planning
| "Surf's Up" Web Sites to Remember | |
[Top]
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| Ed Christopher (Census Subcommittee Chair)
PH: 202-366-0412 FAX: 202-366-3640 EdC@TRBcensus.com |
Chuck Purvis (Urban Data Committee Chair)
PH: 510-464-7731 FAX: 510-464-7848 cpurvis@mtc.ca.gov |
| Ed Limoges (Census Subcommittee Secretary)
PH: 313-961-4266 FAX: 313-961-4869 limoges@semcog.org |
Ron Tweedie (State Data Committee Chair)
PH: 518-457-1695 FAX: 518-457-8317 rtweedie@gw.dot.state.ny.us |
Census Population Division (JTW questions)
| Phil Salopek
PH: 301-457-2454 FAX: 301-457-2481 phillip.a.salopek@ccmail.census.gov |
Clara Reschovsky
PH: 301-457-2454 FAX: 301-457-2481 clara.a.reschovsky@ccmail.census.gov |
Census Geography Division (for TAZ-UP questions)
| Jamie Rosenson
PH: 301-457-1099 FAX: 301-457-4710 jrosenson@geo.census.gov |
Valerie Murdock
PH: 301-457-1099 FAX: 301-457-4710 vmurdock@geo.census.gov |
Bob LaMacchia
PH: 301-457-1022 FAX: 301-457-4710 rlamacchia@geo.census.gov |
FHWA
| Elaine Murakami
PH: 202-366-6971 FAX: 202-366-7742 elaine.murakami@fhwa.dot.gov |
Nanda Srinivasan
PH: 202-366-5021 FAX: 202-366-7742 nanda.srinivasan@fhwa.dot.gov |
Mark Sarmiento
PH: 202-366-4828 FAX: 202-366-3713 mark.sarmiento@fhwa.dot.gov |
| BTS
Ed Christopher (See under TRB Committees) |
FTA
Paul Branch PH: 202-366-6694 FAX: 202-493-2478 paul.branch@fta.dot.gov |
FTA
Jim Ryan PH: 202-366-0954 FAX: 202-493-2478 james.ryan@fta.dot.gov |
AASHTO
Deborah Buchacz PH: 202-624-5839 FAX: 202-624-5806 debbieb@aashto.org |
