Chapter 5

Tabular Data

Available Data

The TOD Database utilizes nationally available data products that record demographic and travel behavior patterns. Six data products and data sets are currently available in the TOD Database.

US Decennial Census, 2000

US Decennial Census, 2010

American Community Survey (ACS), 2005-09 5 Year Estimates

ACS is an ongoing survey that gathers detailed population and housing data every year. It replaced the long form of the Census. The 5 Year Estimates are rolling averages of data collected between 2005 and 2009. ACS data is aggregated from block groups and tracts.

Census Transportation Planning Package, 2000

CTPP is a special data product synthesized from the Decennial Census long form specifically for transportation planners. The TOD Database uses CTPP data products that were released in 2000. Now that the US Census Bureau has replaced the long form with the American Community Survey, updates to the CTPP are released annually. At present, CTPP using the ACS is only available as a 3-year estimate (2006-2008) at the PUMA level and as a 5-year estimate (2006-2010) at the Transportation Analysis Zone (TAZ) level. Both a PUMA and a TAZ are too large to accurately aggregate down to a transit zone so it is not included in the current release of the Database. However, when ACS data is made available at the Census Block Group level in 2011, CTOD will include it in the TOD Database. At this time, the TOD Database aggregates CTPP 2000 data from Census Tracts.

Local Employment Dynamics, 2002- 2009

LED is a voluntary partnership between the Federal Census Bureau and state labor market information agencies. LED exists under the Longitudinal Employer-Household Dynamics (LEHD) program of the US Census Bureau. The LED partnership offers several data products, one of which is OnTheMap, an interactive online map that allows the display of Workplace Area Characteristics and Residential Area Characteristics, and traces the origin and destination tracts between worker home and work. The TOD Database uses OnTheMap data that is available at the Census Block (using updated 2009 Census Block boundaries).

Housing + Transportation Affordability Index, 200

The Housing + Transportation Affordability Index (H+T® Index) is a proprietary model developed by the Center for Neighborhood Technology that models household travel demand. The H+T Index estimates household transportation expenditures at the block group level based on seven neighborhood variables and three household variables for 940 core based statistical areas. More information is available at Block group H+T data (and Census derived housing data) is aggregated to the transit zone level. Transportation data is modeled for three household types:

Derived Data Fields

There are a number of tables and fields in the Reports section of the Database that have been calculated and aggregated by CTOD during the Database development process that are useful for TOD analysis. A footnote at the bottom of each report describes how a field was derived. The footnote will provide the data set and field names as well as the formula. Some examples of date calculated by CTOD are:


The following density measures are calculated using the 2000 and 2010 Census data.

Data Aggregation

Census data is available at the block, block group and tract level. Most census geographies are not fully contained within a transit buffer, rather, they overlap. To apportion a variable within a tract, the TOD DB utilizes a script that calculates the area and fraction of overlap. The script associates each Census geography (i.e. tract, block, etc.) to the buffer it intersects through a unique ID. The script then calculates the percentage of the object area that is within the transit zone as well as the actual area (in acres). Lastly, the script proportionally aggregates up from each census geography that intersects the buffer.

Median Distances

Median distances are derived by calculating the distances between all origin and destination Census Tracts (for CTPP) and Census Blocks (for LED), and then aggregating the median distance from all distances for each origin and destination tract.