Congress passed the Omnibus Transportation Employee Testing Act, requiring all Departments of Transportation (DOT) to initiate alcohol and drug testing of safety-sensitive transportation employees. 49 C.F.R. Part 40 is a DOT-wide regulation detailing how the testing should happen and how to return employees to safety-sensitive duties if they breach DOT alcohol and drug regulations.
Part 40 applies to all DOT-required testing, no matter the mode of transportation. Each DOT Agency-specific regulation explains who is subject to testing, when they need to complete testing, and in what situations for which transportation industries.