The CTPP 5-year data, based on ACS 2006 – 2010 Census Data, will be released tomorrow Thursday, October 31, 2013, the URL to access the data will be published here.

The CTPP Data Access Software is a powerful tool to access the nearly 350 gigs of data provided by the Census Bureau.  The Data set consists of nearly 200 residence based tables, 115 workplace based tables and 39 flow tables (Home to work) for over 200,000 geographies.  The data are derived from two American Community Survey microdata record sets based on the 2006 – 2010 ACS. One set is the original microdata; all tables derived from this set are designated A, the other set is a disclosure proofed microdata set; all tables derived from this set are designated B.  That is to say, the first letter in the table name indicates the set from which the table was derived.  For more information on disclosure proofing, please access the CTPP e-Learning module “Disclosure Proofing” at: http://ctpp.training.transportation.org/

The software contains a robust map tool, for both selecting geography and rendering results.  Results can also be presented as various style charts and tables that can be rearranged to suit your analysis and display needs. Data from the tool can be downloaded as comma or semi colon delimited .csv, .xml, .shp, .tab.

Some things to be aware of:

This is a new software release and it is possible you may find some errors and bugs as you use it. Please use the CTPP Feedback form available in the Help menu to report any problems encountered. (Version 1.1 release, already planned for the near future, reflects corrections to issues discovered after Beta testing.) Please consider this a Gamma version.

A PDF tutorial is available in the Help menu and covers much of the software functionality teaching a sample application.  The context sensitive (on-line) help has some bugs that are currently being addressed.  A series of short film tutorials is available on the CTPP YouTube channel at: http://www.youtube.com/user/CTPPProgram.  The YouTube tutorials include a software tour, how to register/logon, opening and rearranging a table/accessing basic data; Geography selection by list and map; Calculating percentages; and Display maps and thematic analyses.  If, after you have exhausted all resources you are still having trouble please contact pweinberger@aashto.org  for a walk through, but please try to find your solution from available resources first.  Training is rolling out both in person and online, we will keep you posted.

Downloads are limited to 100,000 cells.  If you need to download large tables they will need to be split up and stitched back together in excel (or another program).  We are developing a background downloader for large files. In the meantime, if you simply want all the data for your entire area, send a message to pweinberger@aashto.org and a set with appropriate documentation will be made available for FTP download. Any very large data set is unsupported and for power users, comfortable manipulating large data sets in statistical software packages that they are already licensed to use.

Geographies can be aggregated and margins of error will be correctly re-calculated, but non-standard (user created) saved geographies cannot be mapped – we are working on this.

Until approximately January 2014, the data set available does not include workplace data for TAZs with zero (0) populations. This means that any TAZ which consists solely of a special generator (i.e., an airport, a shopping mall, a business park, the pentagon, etc.) does not have its associated workplace data or flow to it available.  This is being rectified and a new dataset will be released around January, 2014 that corrects that problem.  Fortunately, the data is available at tract even for zero pop tracts, so you can get the data at smallish, just not smallest, level  and you can do TAZ to Tract flows

Penelope Z. Weinberger

CTPP Program Manager

AASHTO

202-624-3556

ctpp.transportation.org