Before we get into the mechanics of how the DOT testing program operates, it’s important to understand why it exists in the first place.

Transportation jobs demand clear thinking, coordination, and the ability to react quickly in unpredictable situations. Even small lapses can put lives at risk. To reduce this danger, the Department of Transportation requires drug and alcohol testing across roles like trucking, aviation, rail, and transit.

The testing program has two main purposes: to deter employees from using substances in the first place, and to detect violations before they cause harm. In other words, the program is not just about catching mistakes — it’s about preventing them. This creates a culture of accountability where everyone in transportation can trust that the people around them are unimpaired and alert.

The Safety Bottom Line: DOT testing exists to prevent impairment and protect lives, not just to punish violations.