1. American Society of Civil Engineers Infrastructure, “2017 Infrastructure Report Card,” 2017.
2. American Society of Civil Engineers, “Failure to Act: Closing the Infrastructure Investment Gap for America’s Economic Future,” 2016.
3. US Census Bureau Data, 2019.
4. United Nations DESA Population Division, “World Population Prospects: 2019,” 2019.
5. Federal Highway Administration, “State Motor Vehicle Registrations, By Years, 1900-1995,” 1995.
6. Federal Highway Administration, “State-Motor Vehicle Registrations – 2017,” January, 2019.
7. American Society of Civil Engineers Infrastructure, “2017 Infrastructure Report Card,” 2017.
8. United Nations DESA Population Division, “World Urbanization Prospects: 2018,” 2018.