Why does the ACS ask such detailed questions?
We ask these questions because federal and state government require the data that we collect to manage or evaluate programs. For example, information about utilities is used by the U.S. Department of Housing and Urban Development, the U.S. Department of Energy, and the U.S. Department of Agriculture to administer their programs. Journey-to-work information, such as what time you leave your home, is used by federal and state government transportation planning agencies for roads and public transit development.
Read more about the purposes of each question at: http://www.census.gov/acs/www/about/why-we-ask-each-question/.
Please note that the topics on the American Community Survey (ACS) are nearly identical to those topics asked in the 2000 Census long form questionnaire.