1. American Society of Civil Engineers (ASCE). (2017). 2017 Infrastructure Report Card. https://www.infrastructurereportcard.org/ (July 15, 2017).
2. American Society of Civil Engineers (ASCE). (2016). Failure to Act Report. https://www.infrastructurereportcard.org/wp-content/uploads/2016/10/ASCE-Failure-to-Act-2016-FINAL.pdf (July 15, 2017).
3. Department of Homeland Security (DHS). 2017. Transportation Systems Sector. https://www.dhs.gov/transportation-systems-sector (July 15, 2017).
4. Association of American Railroads (AAR). (2017). The Economic Impact of America’s Freight Railroads. https://www.aar.org/BackgroundPapers/Economic%20Impact%20of%20US%20Freight%20Railroads.pdf (July 15, 2017).
5. Association of American Railroads (AAR). (2017). Overview of America’s Freight Railroads. https://www.aar.org/BackgroundPapers/Overview%20of%20America's%20Freight%20RRs.pdf (July 15, 2017).