DOT’s drug and alcohol testing program is one of the strongest safeguards in transportation. While cannabis is often in the spotlight, the rules apply to a full range of substances — from cocaine to opioids to amphetamines — because any impairment can put lives at risk.

In this chapter, you’ll learn:

• Why research on cannabis is still limited, and why that matters for safety.
• How DOT’s testing program works — from pre-employment to random to post-accident tests.
• What substances are on the DOT testing panel.
• How prescription medications are handled differently from marijuana, and why THC is always a violation.

By understanding how and why these regulations exist, you’ll see how your role as a safety-sensitive employee helps protect not just your career, but your coworkers and the public you serve.