1. Federal Highway Administration. Highway Safety Improvement Program (HSIP). https://www.fhwa.dot.gov/safety/legislative-safety-programs/hsip/about-hsip. Accessed on September 21, 2015.
2. Federal Highway Administration. Railway-Highways Crossing (Section 130) Program. https://www.fhwa.dot.gov/safety/legislative-safety-programs/xings/program-overview. Accessed on September 30, 2015.
3. Federal Highway Administration. Railway-Highway Crossings Program Reporting Guidance. https://www.fhwa.dot.gov/map21/guidance/guiderhcp.cfm. Accessed on September 20, 2015.
4. Federal Highway Administration. Performance Based Planning and Programming Guidebook. September 2013.
5. Iowa Department of Transportation, Office of Rail Transportation. State of Iowa Highway-Rail Grade Crossing Safety Action Plan. August 2012.
6. Louisiana Department of Transportation and Development. Crossing Safety Action Plan Report. August 2011.
7. Texas Department of Transportation. Texas Highway-Rail Grade Crossing Safety Action Plan. August 2011.