The data on means of transportation to work were derived from answers to Question 31, which was asked of people who indicated in Question 29 that they worked at some time during the reference week. (See "Reference Week".) Means of transportation to work refers to the principal mode of travel or type of conveyance that the worker usually used to get from home to work during the reference week.

People who used different means of transportation on different days of the week were asked to specify the one they used most often, that is, the greatest number of days. People who used more than one means of transportation to get to work each day were asked to report the one used for the longest distance during the work trip. The category, "Car, truck, or van", includes workers using a car (including company cars but excluding taxicabs), a truck of one-ton capacity or less, or a van. The category, "Public transportation", includes workers who used a bus or trolley bus, streetcar or trolley car, subway or elevated, railroad, or ferryboat, even if each mode is not shown separately in the tabulation. "Carro público" is included in the public transportation category in Puerto Rico. The category, "Other means," includes workers who used a mode of travel that is not identified separately within the data distribution. The category, "Other means," may vary from table to table, depending on the amount of detail shown in a particular distribution.

The means of transportation data for some areas may show workers using modes of public transportation that are not available in those areas (for example, subway or elevated riders in a metropolitan area where there is no subway or elevated service). This result is largely due to people who worked during the reference week at a location that was different from their usual place of work (such as people away from home on business in an area where subway service was available), and people who used more than one means of transportation each day but whose principal means was unavailable where they lived (for example, residents of nonmetropolitan areas who drove to the fringe of a metropolitan area, and took the commuter railroad most of the distance to work).

The data on place of work were derived from answers to Question 30, which was asked of people who indicated in Question 29 that they worked at some time during the reference week. (See "Reference Week.")
Data were tabulated for workers 16 years old and over, that is, members of the Armed Forces and civilians who were at work during the reference week. Data on place of work refer to the geographic location at which workers carried out their occupational activities during the reference week. In the American Community Survey, the exact address (number and street name) of the place of work was asked, as well as the place (city, town, or post office); whether the place of work was inside or outside the limits of that city or town; and the county, state or foreign country, and ZIP Code. In the Puerto Rico Community Survey, the question asked for the exact address, including the development or condominium name, as well as the place; whether or not the place of work was inside or outside the limits of that city or town; the municipio or U.S. county. Respondents also were asked to enter Puerto Rico or name of U.S. state or foreign country and the ZIP Code. If the respondent's employer operated in more than one location, the exact address of the location or branch where he or she worked was requested. When the number and street name were unknown, a description of the location, such as the building name or nearest street or intersection, was to be entered. People who worked at more than one location during the reference week were asked to report the location at which they worked the greatest number of hours. People who regularly worked in several locations each day during the reference week were requested to give the address at which they began work each day. For cases in which daily work did not begin at a central place each day, the respondent was asked to provide as much information as possible to describe the area in which he or she worked most during the reference week.

Place-of-work data may show a few workers who made unlikely daily work trips (e.g., workers who lived in New York and worked in California). This result is attributable to people who worked during the reference week at a location that was different from their usual place of work, such as people away from home on business.

In areas where the workplace address was geographically coded to the block level, people were tabulated as working inside or outside a specific place based on the location of that address regardless of the response to Question 30c concerning city/town limits. In areas where it was impossible to code the workplace address to the block level, or the coding system was unable to match the employer name and street address responses, people were tabulated as working inside or outside a specific place based on the combination of state, county, ZIP Code, place name, and city limits indicator. The city limits indicator was used only in coding decisions when there were multiple geographic codes to select from, after matching on the state, county, place, and ZIP Code responses. The accuracy of place-of-work data for census designated places (CDPs) may be affected by the extent to which their census names were familiar to respondents, and by coding problems caused by similarities between the CDP name and the names of other geographic jurisdictions in the same vicinity.

Place-of-work data are given for selected minor civil divisions (MCDs), (generally cities, towns, and townships) in the 12 strong MCD states (Connecticut, Maine, Massachusetts, Michigan, Minnesota, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, Vermont, and Wisconsin), based on the responses to the place of work question. Many towns and townships are regarded locally as equivalent to a place, and therefore, were reported as the place of work. When a respondent reported a locality or incorporated place that formed a part of a township or town, the coding and tabulating procedure was designed to include the response in the total for the township or town.

The American Community Survey Summary Files include all detailed tables for all geographic areas published by the 2009 1-Year ACS. The main directory of the American Community Survey' s Summary File product release, located within the file transfer protocol (FTP) site, contains documentation about the Summary Files, information pertaining to the United States, each of the individual states, the District of Columbia, and Puerto Rico. The following list outlines the hierarchical geographic levels contained within the Summary File release.

Geographic Component	Summary Level
00, 01, 43, A0, C0, C1, C2, E0, E1, E2, G0, H0, 89, 91-94	010 United States1
00, 01, 43, A0, C0, C1, C2, E0, E1, E2, G0, H0	020 Region1
00, 01, 43, A0, C0, C1, C2, E0, E1, E2, G0, H0	030 Division1
00, 01, 43, A0, C0, C1, C2, E0, E1, E2, G0, H0	040 State2
55-59, 60-62 00	050 State-County3
00	060 State-County-County Subdivision
00	160 State-Place
00	500 State-Congressional District (111th)
00	795 State-Public Use Microdata Area (5%)
00	950 State-School District (Elementary)/Remainder4
00	960 State-School District (Secondary)/Remainder4
00	970 State-School District (Unified)/Remainder4
00	230 State-Alaska Native Regional Corporation
00	250 American Indian Area/Alaska Native Area/Hawaiian Home Land
00	310 Metropolitan Statistical Area/Micropolitan Statistical Area
00	312 Metropolitan Statistical Area/Micropolitan Statistical Area-State-Principal City
00	314 Metropolitan Statistical Area/Micropolitan Statistical Area-Metropolitan Division
00	330 Combined Statistical Area
00	335 Combined New England City and Town Area
00	350 New England City and Town Area
00	352 New England City and Town Area-State-Principal City
00	355 New England City and Town Area (NECTA)-NECTA Division
00	400 Urban Area

Footnotes:

¹Land area, water area, population counts, and housing unit counts for the United States, Regions, and Divisions do not include Puerto Rico.

²State, District of Columbia, or Puerto Rico.

³Parish in Louisiana, Borough or Census Area in Alaska, and Municipio in Puerto Rico; in Maryland, Missouri, Nevada, and Virginia, one or more cities are independent of counties and are treated as statistical equivalents of counties; the entire District of Columbia, which has no counties, is treated as a county equivalent.

⁴Remainder of school districts are published for ACS 5-year data.