Reasonable Suspicion Testing: What Supervisors Need to Know

What "Reasonable Suspicion" Actually Means

Under DOT rules, reasonable suspicion testing is based on specific, contemporaneous, articulable observations made by a trained supervisor. The observation must relate to the employee's appearance, behavior, speech, or body odor. These observations must be specific — not a general feeling or a rumor, and not based on another employee's report without the supervisor personally observing the indicators.

"Contemporaneous" means the observation is current — what the supervisor is seeing right now, not something from last week. The supervisor cannot base a reasonable suspicion determination on past behavior, a history of problems, or anything they did not directly observe during the current work period.

Observable Indicators That May Qualify

Indicators that support a reasonable suspicion determination include:

• Slurred, incoherent, or unusually slow speech
• Glassy, bloodshot, or watery eyes
• Odor of alcohol or marijuana
• Unsteady gait or impaired coordination
• Erratic, unusual, or agitated behavior inconsistent with the employee's normal demeanor
• Extreme drowsiness or difficulty staying awake
• Constricted or dilated pupils
• Slowed or confused responses to normal workplace instructions

No single indicator is automatically sufficient. The supervisor is evaluating the totality of what they observe. Two or more clear indicators generally provide a stronger basis for a determination than one indicator alone.

What Does Not Qualify

Reasonable suspicion is not:

• A tip or complaint from a coworker
• An employee's prior positive test or prior discipline
• A supervisor's "gut feeling" without specific observations
• An employee being involved in a minor incident without observable impairment signs
• An employee's request to leave early or unusual absenteeism alone

Using any of these as the basis for a reasonable suspicion test without direct, documented observation creates a legal vulnerability. An employee who challenges the test will likely prevail if the employer cannot point to specific, firsthand observations made at the time of the determination.

The Role of Supervisor Training

DOT regulations require that supervisors who authorize reasonable suspicion testing receive specific training: at least 60 minutes on controlled substances and 60 minutes on alcohol misuse. This training covers the physical, behavioral, and performance indicators of drug and alcohol use. Without this training, a supervisor's determination — even if accurate — may not be defensible.

Training records must be maintained. If you're audited or if the test result is challenged, you'll need to demonstrate that the authorizing supervisor had completed the required training before the determination was made.

What to Do After Making a Determination

Once a reasonable suspicion determination is made, move quickly and methodically:

1. The supervisor documents their specific observations in writing, including the date, time, location, and a description of what they saw and heard
2. The employee is directed to report for testing — for alcohol, this must happen within 2 hours if possible, no later than 8 hours
3. The employee must not operate a commercial motor vehicle or perform any safety-sensitive function until the test is complete and the result is received
4. If the employee refuses to submit to testing, treat it as a refusal — which is equivalent to a positive result under DOT rules
5. The supervisor's written documentation is retained in the testing records

Keeping the Employee Safe During the Process

If the supervisor believes the employee is impaired, do not allow them to drive themselves to the collection site. Arrange transportation. The goal of removing an employee from safety-sensitive duty is to prevent a potential accident — undermining that goal by allowing a potentially impaired employee to drive defeats the purpose of the testing occasion entirely.