Grabowski, David C.; Morrissey, Michael A. (2004). "Gasoline Prices and Motor Vehicle Fatalities". Journal of Policy Analysis and Management. 23 (3): 575–593. doi:10.1002/pam.20028.
Hitzemeyer, Erwin G.; Wilde, Helmut; Ellenberger, Donald (1977), "What Color Should Rear Turn Signals Be?", SAE Technical Paper Series, vol. 1, Society of Automotive Engineers - Technical Papers, doi:10.4271/770812, retrieved March 31, 2022
Federal Highway Administration (2006). "Chapter 14 Freight Transportation". 2006 Status of the Nation's Highways, Bridges, and Transit: Conditions and Performance. United States Department of Transportation. Archived from the original on August 23, 2007. Retrieved December 21, 2020.
Hitzemeyer, Erwin G.; Wilde, Helmut; Ellenberger, Donald (1977), "What Color Should Rear Turn Signals Be?", SAE Technical Paper Series, vol. 1, Society of Automotive Engineers - Technical Papers, doi:10.4271/770812, retrieved March 31, 2022
"Budget Estimates, Fiscal Year 2018"(PDF). National Highway Traffic Safety Administration. United States Department of Transportation. Retrieved September 9, 2021.
"Budget Estimates, Fiscal Year 2025"(PDF). National Highway Traffic Safety Administration. United States Department of Transportation. Retrieved April 4, 2024.
Federal Highway Administration (2006). "Chapter 14 Freight Transportation". 2006 Status of the Nation's Highways, Bridges, and Transit: Conditions and Performance. United States Department of Transportation. Archived from the original on August 23, 2007. Retrieved December 21, 2020.