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www.census.gov/population/projections/data/national/2014/summarytables.html
(2015). Accessed 20 June 2016
2. Mather, M., Pollard, K., Jacobsen, L.A.: First results from the 2010 census.
www.prb.org/pdf11/reports-on-america-2010-census.pdf
(2011). Accessed 20 June 2016
3. U.S. Census Bureau, Population Estimates.
www.census.gov/popest/data/historical/index.html
(2015). Accessed 20 June 2016
4. FHWA, Forecast of Vehicle Miles Traveled, May 2015.
www.fhwa.dot.gov/policyinformation/tables/vmt/vmt_forecast_sum.pdf
. Accessed 20 June 2016
5. FHWA, Traffic Volume Trends.
www.fhwa.dot.gov/policyinformation/travel_monitoring/tvt.cfm
(2015). Accessed 20 June 2016