Users' Comment on Proposed CTPP Tabs
By Sherry Riklin, US DOT, Office of Transportation Policy Development
The CTPP user community has submitted a range of excellent comments on the proposed CTPP 2000 tabulations. User comments focused on table and variable definitions and ranged from refinement of variable categorizations to recommendations that the same worker characteristics be presented in both the place of residence and the place of work tabulations. The CTPP Working Group solicited user comments in July, posting the proposed tabulations, a description of the contents and the variable definitions on the web. The Working Group has been developing the content and format of the proposed CTPP 2000 tabulations over the past year.
The CTPP user community suggested a number of new tables to increase our understanding of the characteristics of persons with mobility limitations, the relationship between household characteristics and vehicle ownership and the relationship between worker characteristics and travel choices. One significant recommendation was to "mirror" the "place of residence" tables and the "place of work" tables for "all workers", and for "workers in households".
"Mirrored" tables will enable CTPP users to estimate the flow of workers from their place of residence to their place of work by household and worker characteristics. With techniques such as Fratar or Iterative Proportional Fitting (IPF), users can estimate worker flow tables that will not be included in the CTPP 2000 standard tabulations.
The user community also suggested refinements to the variable categories. These comments focused on the categorization of the age variable, the number of household children, the number of household workers, the number of household vehicles and the reported combinations of modes.
The Working Group has revised the proposed tabulations to reflect the comments of the CTPP user community. The revised listing of the proposed tables can be found at www.mcs.com/~berwyned/census/content.html. The Working Group will now seek the US Census Bureau's Disclosure Review Board's approval to include the revised tabulations in the CTPP 2000 package.
Note: Sherry Riklin, FTA, recently transferred to the Office of the Secretary along with a promotion. We thank her for representing the FTA on the CTPP Working Group and wish her "good luck" at her new job. Keep in touch Sherry!
The Lane Council of Governments (LCOG), Metropolitan Planning Organization for Eugene-Springfield, Oregon, has found new uses for data from the 1980 Urban Transportation Planning Package (UTPP), predecessor to today's CTPP. We have been working with an interdisciplinary team from the University of Washington to develop an integrated Land Use / Transportation model for the Eugene-Springfield area. The land use modeling component, UrbanSim, is a behavioral model designed to simulate complex interactions among households, businesses, and developers within the urban markets for land, labor, housing, non-residential space, and transportation. UrbanSim works iteratively with the region's transportation model, using accessibility output from the model, and providing land use input for the next iteration.
The impacts of government land use actions and infrastructure investments take place over very long periods of time. Thus, it requires a tremendous amount of historical data to calibrate and validate a behavioral model to simulate those effects. LCOG has a rich tradition of developing and maintaining high-quality demographic, economic, and land use data for Eugene-Springfield, which was one reason the area was selected as a site for initial implementation of UrbanSim.
With a 1980 metropolitan area population of about 180,000 persons, our planners placed high priority on obtaining UTPP demographic, workplace, and journey-to-work data through a contract with the Census Bureau. That investment has yielded substantial returns over time. In 1999, UrbanSim staff conducted a 1980-to-1994 longitudinal calibration of the integrated model. We employed a variety of 1980 data resources, but found that the UTPP data filled some critical needs. It was the only historic demographic data compiled at the Transportation Analysis Zone (TAZ) level. Many of our TAZ's have been subdivided since 1980, but 'parent zone' boundaries have remained largely unchanged. The ability to aggregate data to a consistent set of TAZ boundaries facilitates comparisons of data from the 1980 UTPP, and the 1990 and 2000 CTPP's, and enables tracking of demographic, employment, and work travel changes over time.
TAZ households from the UTPP, tabulated by number of persons, workers, income, and vehicles, were important inputs to UrbanSim and the transportation model. We also developed home-based-work trip tables for each mode of travel, using "Means of transportation to work" data by Residence and Workplace, and assuming 1.81 daily HBW person-trips per UTPP journey-to-work trip. These trip tables were used to validate work trip generation, distribution, and mode choice for a 1980 transportation model "backcast."
For more information, please contact Bud Reiff at email@example.com
Note: The 1980 UTPP was not developed as a nationwide package. Individual organizations contracted with the Census Bureau and obtained the package of special standard tabulations.
Census 2000 Redistricting Data
Congress passed Public Law (PL) 94-171 in 1975 offering states the opportunity to receive population totals for election precincts and similar areas. From 1980 onwards, participating states have been receiving population data by race at the block level to support redistricting. The PL-94-171 file is based on 100 percent count (Census Short Form) and contains the most detailed information on the location of the total population by race and Hispanic/Latino origin; and population over the age of 18 (voting population) by race and Hispanic/Latino origin.
The PL-94-171 file is important because it is the first product released from the decennial census for small area geography. The data for 2000 will be released by April 1, 2001 and will be available via the internet and on CD-ROM. The file will contain:
For those organizations which defined TAZs for TIGER/Line 2000, a TAZ field will be included in the file, so that users can aggregate blocks into TAZ summaries.
The PL-94-171 file constitutes an important data source for transportation planning concerns such as Environmental Justice (EJ) analysis. The data can be used to analyze the concentrations of minority population groups. Since the data are released at the block level, it allows precise spatial analysis, which in turn, can help in analysis of impacts (benefits and burdens) of transportation related projects on different groups.
For more information on the redistricting program, please visit: http://factfinder.census.gov/.
TIGER/Line 2000: Redistricting Version
The TIGER/Line files are a digital database of geographic features, such as roads, railroads, rivers, lakes, political boundaries, census statistical boundaries, etc. covering the entire United States. The Census Bureau plans to release a version of TIGER/Line 2000 by January-February of 2001 to accompany the PL-94-171 redistricting data. This file will contain the final TAZ layer for all areas which participated in the TAZ-UP program. However, it will not contain Zip Code Tabulation Areas (polygon areas derived from post office zip codes) and will not include the new address ranges obtained in 2000. A second release of redistricting Census 2000 TIGER/Line files containing all the updated information will be released after March 2001.
The Census Bureau has released test files and documentation for TIGER/Line 2000 on the internet at:
|Note: In the spirit of expanding our horizon on transportation data sources, we are trying to have a series of articles on TRB data committees in future CTPP Status Reports. This issue of the Status Report focuses on the TRB Committee on Statewide Transportation Data and Information Systems (A1D09).|
The scope of A1D09 includes research and technology transfer activities pertaining to statewide transportation planning data and information systems for all modes of transportation. In addition to seeking out new sources of data for statewide planning, the committee is particularly concerned with the integration of transportation related data across modes and jurisdictions.
Committee membership is geographically and professionally diverse. Approximately one-half of the members are from state DOTs with the remaining one-half coming from the academic, federal government and MPO arenas.
This year has been a particularly active time for A1D09. In addition to the normal committee activities, we convened a Peer Exchange meeting on August 25 and 26 in Madison, Wisconsin. The main theme of the Peer Exchange was performance measures in transportation, and, in particular, the data and data systems that underlie performance measures in a multimodal system planning and management context. Nine State DOT members provided descriptions of how their agencies have developed and are using performance measures; and how this has shaped data collection, processing, and analysis activities. In addition to the technology transfer benefits attained at the Peer Exchange, a written summary of the meeting has been prepared by Steve Pickrell of Cambridge Systematics. This summary will be available through normal TRB channels. Based upon the meeting discussions five research statements have been prepared for submittal to TRB.
In October several members of A1D09 were active participants in a Conference on Performance Measures to Improve Transportation Systems and Agency Operations held at the Beckman Center in Irvine, California. The purpose of the conference was to bring together leaders in the transportation field to review experience to date and develop guidance material and a research agenda to support the effective use of performance measures in transportation. The results of the Madison Peer Exchange were an input to the conference. The Madison summary document will be included in the conference proceedings.
The Committee's plans for the 2001 Annual TRB meeting include sponsorship of two sessions and participation in others. Session 26 -- Statewide Transportation Data and Analysis Techniques - presents four papers on the statewide data theme. Session 61 -- Data Requirements for State System Performance Measures - will present a summary of our Madison Peer Exchange on performance measures and also include a panel to comment on the future directions. Session 369 - Views of Transportation Data's Future -- will focus on 21st Century data needs from several perspectives. The A1D09 Committee meeting will be held on Tuesday, January 9th, from 8 a.m. till noon in the Hilton International West room.
Plans for 2001 are rounding into shape. A1D09 will be one of four sponsoring committees of a Peer Exchange on Integrating Highway Information which will be held March 22 and 23, 2001 in Washington, DC. Several state DOT's will be invited to share their experiences in data integration within their organizations.
From July 19-24 A1D09 will join with the Planning, Finance and Management committees for the Mid-year meeting in Vail, Colorado. Paul Bingham's Freight Committee and Alan Pisarski's National Data Committee will also participate. A1D09 will also hold our second Peer Exchange in conjunction with the Mid-year meeting. Topics are currently under discussion but will likely focus on data integration issues.
Last, but certainly not least, I want to thank all my committee members for their active involvement in our activities and also Tom Palmerlee, TRB staff, for his excellent support. His dogged determination that committees should work and his direct involvement have made a big difference in our committee accomplishments---Thanks Tom.
|Note: TRB Data Committees A1D08 -- Urban Transportation Data, chaired by Chuck Purvis; and A1D10 -- Travel Survey Methods, chaired by Elaine Murakami, will have their committee mid-year meetings on Sunday, April 22, 2001 in conjunction with the Eighth TRB Conference on the Application of Transportation Planning Methods, Corpus Christi, Texas, April 22-26, 2001.|
Outreach is a key component of CTPP 2000. Many of the members of the CTPP Working Group will be attending several conferences. The following is a list of conferences where CTPP is included in the agenda for January 2000 -- March 2001.
When there are 200 projects submitted and only five or six get chosen, securing votes is essential.
This is the case with our National Cooperative Highway Research Program (NCHRP) proposal dealing with the use of the American Community Survey (ACS) data. Last Spring, several individuals and states submitted what is now NCHRP proposal 2002-B-06. The proposal went though several reviews and has advanced to what is now known as a "Second Stage Problem Statement". A copy of the Second stage proposal can be found at www.mcs.com/~berwyned/census/notes/nchrp2002b06.html
Under the rules of the NCHRP selection process, a proposal in stage two is put out for review to the AASHTO Standing Committee on Research (SCOR) and its affiliate Research Advisory Council (RAC). The members of these two committees rate all the proposed research statements. The results of their ratings are then used to set the order in which the research statements will be discussed at a March 2001 SCOR meeting where the "winners" will be selected.
The RAC is made up of one individual from each state. In early December each RAC member received a copy of all the stage two statements. They will have until the end of January to complete their review. At the same time the RAC review is proceeding, the members of the AASHTO SCOR committee will also be ranking the projects.
To help advance the ACS project we need our CTPP contacts and our transportation planning community friends to make sure that their states' RAC member understands that this research is extremely important. In short, we need to make sure that research statement 2002-B-06 "Using American Community Survey Data for Transportation Planning" receives a high rating.
If you are in a state DOT, you likely know your RAC member. If you are in an MPO, you should have your agency write or contact your state's Planning Director to let them know the importance of this proposal. They in turn can pass along your formal support to the RAC member.
Remember there are upwards of 200 research proposals being considered. So please show your support and contact your RAC member today.
Chair, TRB Sub-committee on Census Data for Transportation Planning
Note: The Sub-committee meeting at TRB Annual Meeting will be held on Monday, January 8, 2001, between 8:00-11:00 a.m. at the Hilton, Bancroft room.
Interested in Defining Your Metropolitan Public Use Microdata Sample Zones? If so please contact your State Data Center as soon as possible and let them know of your desire. To find the State Data Center closest to you, please visit http://www.census.gov/sdc/.
|"Surf's Up" Web Sites to Remember|
|CTPP Hotline 202-366-5000|
|Ed Christopher (Census Subcommittee Chair)
|Chuck Purvis (Urban Data Committee Chair)
|Ed Limoges (Census Subcommittee Secretary)
|Ron Tweedie (State Data Committee Chair)
Census Population Division (JTW questions)
Census Geography Division (for TAZ-UP questions)
(206-220-7642 in Seattle)
Ed Christopher (Census Subcommittee Chair)
For up-to-date Regional Census Center information go to http://www.census.gov/field/www/