Use Census ACS API to download raw census data about commuting and population

[liezl200]

See here: http://cran.r-project.org/web/packages/acs/acs.pdf

Relevant data sets:

ACS DEMOGRAPHIC AND HOUSING ESTIMATES: 2006-2010 American Community Survey 5-Year Estimates (Found through manual search on FactFinder)

The below datasets were found at http://www.census.gov/population/metro/data/other.html.
Table 1. Residence County to Workplace County Flows for the United States and Puerto Rico Sorted by Residence Geography: 2006-2010 [XLSX - 7.2M]
Table 2. Residence County to Workplace County Flows for the United States and Puerto Rico Sorted by Workplace Geography: 2006-2010 [XLSX - 7.0M]
Table 5. Number of Workers in Workplace Geography (State-County-Place) for the United States and Puerto Rico: 2006-2010

[erispoe]

Great that you found the ACS package.
There is also a Census set of web APIs:
http://www.census.gov/data/developers/data-sets.html

[liezl200]

Thanks, I'll also look into http://www.census.gov/acs/www/data_documentation/documentation_main/ which is accessible through the link you provided.