What is CTPP?
Why don't the numbers add up?
Why isn't my home community in the list?
Where does the information for this web site come from?
What is a Census Designated Place (CDP)?
Where can I find a list of definitions used on this website?

What is CTPP?

Census Transportation Planning Package (CTPP). CTPP 2000 is a special tabulation of responses from households completing the Census long form. The special tabulation is intended to provide data to support a wide range of transportation planning activities. It is the only Census product that summarizes data by place of work and tabulates the flow of workers between home and work. And it is the only source of information with summary tabulations available for traffic analysis zones (TAZ's) that have been defined by State and regional transportation agencies.
http://www.trbcensus.com/ctpp.html#intro

Why don't the numbers add up?

All of the data values in CTPP 2000 have been independently rounded. Total expanded census values that range from 1 to 7 are rounded to "4" and values above 7 are rounded to the nearest even multiple of five, e.g., 5, 10, 15, 20, etc. For more discussion of the rounding issue, please read the April 2004 edition of the CTPP 2000 Status Report (PDF format).

Why isn't my home community in the list?

CTPP data are available for all Census Designated Places (CDP) with population 2,500 or more. There are 306 CDP's in Florida with population below 2,500.

Where does the information for this web site come from?

The data is from the Census Transportation Planning Package, which is derived from the 2000 census long form. For data that pertains to resident based trips, the data was acquired from Part A of the CTPP. Work based data was acquired from Part B of the CTPP, and all Flow data, (the source of the maps showing the flows in and out of Places) are from the Part C of the CTPP.

The CTPP State Part A: By place of residence provides summary tables that describe persons, household and workers characteristics by place of residence. The tables are available for a place (area with population 2500 or more), county or state.

Data Parts:

PART A: AT RESIDENCE TABULATIONS

The "at residence" tables are organized into six distinct groups, reflecting the content:

• Characteristics of Persons
• Characteristics of All Households
• Characteristics of All Workers
• Characteristics of Workers by Residence Type
• Characteristics of Housing Units
• Computed Tables

The CTPP, State Part B: By place of work summarizes information about workers such as industry, sex, age, occupational class and time of arrival at work by place of work. The tables are available for a place (area with population 2500 or more), county or state.

PART B: AT WORKPLACE TABULATIONS

The "at workplace" tables are organized into three distinct groups, reflecting the content:

• Characteristics of All Workers
• Characteristics of Workers in Households
• Computed Tables

The CTPP State Part C: Journey-to-Work (JTW) provides detailed information about the commute trip from home to work, allowing the user to obtain such information as the origin and destination of each commuting trip, the travel time of the trip, when the trip began or ended including persons per vehicle and travel mode. The tables are available for a place (area with population 2500 or more), county or state.

PART C: WORKER FLOWS

The "worker flow" tables provide information on the number of workers from the residence to the workplace, their household characteristics and their work travel behavior. This information is organized into two distinct groups, reflecting the content:

• Flows and Times
• Computed Tables

What is a Census Designated Place (CDP)?

Definitions:

Census designated places (CDPs) are delineated for each decennial census as the statistical counterparts of incorporated places. CDPs are delineated to provide data for settled concentrations of population that are identifiable by name but are not legally incorporated under the laws of the state in which they are located. The boundaries usually are defined in cooperation with local or tribal officials. These boundaries, which usually coincide with visible features or the boundary of an adjacent incorporated place or other legal entity boundary, have no legal status, nor do these places have officials elected to serve traditional municipal functions. CDP boundaries may change from one decennial census to the next with changes in the settlement pattern; a CDP with the same name as in an earlier census does not necessarily have the same boundary.

There are no population size requirements for the CDPs designated in conjunction with Census 2000. For the 1990 census and earlier censuses, the U.S. Census Bureau required CDPs to qualify on the basis of various minimum population size criteria.

Beginning with the 1950 census, the U.S. Census Bureau, in cooperation with state and local governments (and American Indian tribal officials starting with the 1990 census), identified and delineated boundaries and names for CDPs. In the data products issued in conjunction with Census 2000, the name of each such place is followed by "CDP," as was the case for the 1990 and 1980 censuses. In the data products issued in conjunction with the 1950, 1960, and 1970 censuses, these places were identified by (U), meaning unincorporated place.

Hawaii is the only state that has no incorporated places recognized by the U.S. Census Bureau. All places shown in the data products for Hawaii are CDPs. By agreement with the state of Hawaii, the U.S. Census Bureau does not show data separately for the city of Honolulu, which is coextensive with Honolulu County.

Where can I find a list of definitions used on this website?

A list of definitions can be found here.