Substance Regulation and Safety Act of 2020 This bill decriminalizes cannabis and contains other related provisions. Specifically, the bill removes marijuana and tetrahydrocannabinols, commonly known as THC, from the schedule of controlled substances and removes references to such substances from various criminal provisions. Such changes related to decriminalization shall be retroactive to apply to cases from before this bill's enactment. The Food and Drug Administration (FDA) shall regulate cannabis products in the same manner as the FDA's regulation of tobacco, including prohibiting any retailer from selling cannabis products to an individual younger than 21 years of age. The bill also requires the Department of Agriculture to promulgate regulations relating to the production and quality control of cannabis, and U.S. Customs and Border Protection to prescribe regulations relating to the import and export of cannabis. The bill also requires each national research institute and national center to (1) evaluate each application for medical research related to cannabis on the same basis as it would any other application for medical research, and (2) not deny an application for financial assistance solely due to the fact that the research relates to cannabis. In addition, the bill requires the Department of Health and Human Services to develop a national strategy to prevent youth use and abuse of cannabis. The National Highway Traffic Safety Administration shall research and publicly report on methods for detecting cannabis-impaired driving. Both the strategy and the research shall address whether any proposed strategies or methods would have racially disparate impacts.