1. US Department of Transportation, Federal Highway Administration. Table VM-1.Accessed February 19, 2021. https://www.fhwa.dot.gov/policyinformation/statistics.cfm
2. Schrank D, Eisele B, Lomax T. Urban Mobility Report. Texas A&M Transportation Institute. 2019;2019:50.
3. DeCorla-Souza P. Congestion Pricing — A Primer: Overview. US Department of Transportation, Federal Highway Administration. 2008:20. Accessed December 26, 2020. https://ops.fhwa.dot.gov/publications/fhwahop08039/cp_prim1_00.htm
4. Federal Highway Administration. Congestion Pricing Strategies.Congestion Pricing. Published March 2, 2020. https://ops.fhwa.dot.gov/congestionpricing/strategies/index.htm. Accessed 19 Feb 2021.
5. Liu Q, Lucas K, Marsden G. Public acceptability of congestion charging in Beijing, China: how transferrable are Western ideas of public acceptability? Int J Sustain Transp. 2020;15(2):97–110. https://doi.org/10.1080/15568318.2019.1695158.