49 C.F.R. § 1.50
The Office of Drug & Alcohol Policy & Compliance advises the Secretary on national and international drug testing and control issues and is the principal advisor to the Secretary on rules related to the drug and alcohol testing of safety-sensitive transportation employees in aviation, trucking, railroads, mass transit, pipelines, and other transportation industries. The Office, in coordination with the Office of the General Counsel, publishes and provides interpretations of rules related to 49 CFR part 40 on the conduct of drug and alcohol tests, including how to conduct tests, and which procedures to use when testing. The Office coordinates with Federal Agencies and assists foreign governments in developing drug and alcohol testing programs and implementing the President's National Drug Control Strategy.
49 C.F.R. §1.50