; and (B) have responsibilities related to maintaining and controlling pipeline in the United States; and (2) indicates whether such operators have sufficient drug and alcohol testing procedures in place to ensure safe operations of pipeline facilities located within the United States. 5. Interstate drug and alcohol oversight (a) In general Not later than 18 months after the date of the enactment of this Act, the Secretary of Transportation shall amend the auditing program for the drug and alcohol regulations in part 199 of title 49, Code of Federal Regulations, in order to improve the efficiency and processes of such regulations as applied to operators and pipeline contractors working for multiple pipeline operators in multiple States. In making such amendments, the Secretary shall minimize duplicative audits of the same operators, and thereby contractors working for those companies, by the Pipeline and Hazardous Materials Safety Administration and multiple State agencies. (b) Limitation Nothing in this Act may be construed to require modification of the inspection or enforcement authority of any Federal agency or State. 6. Impaired driving study (a) Study The Administrator of the National Highway Traffic Safety Administration (referred to in this Act as the NHTSA ) shall conduct a study regarding the ways in which the NHTSA can reduce and better detect impaired driving, including marijuana- and opioid-impaired driving. (b) Reports Not later than 2 years after the date of the enactment of this Act, and biennially thereafter for the following 4 years, the Secretary of Transportation, in cooperation with other Federal agencies, as appropriate, shall submit a report to Congress that— (1) describes the activities undertaken pursuant to subsection (a); (2) provides an update on the progress of the study conducted pursuant to subsection (a)