If you are planning to do a random drug and alcohol testing during a weekend safety meeting, here is what you should know: you can do a Drug test, yes. Alcohol test, no. Since drug use is prohibited at all times, you can conduct random drug tests at any time. But Random alcohol tests must be conducted just before, during or after a driver has performed safety-sensitive functions (e.g., drive). Wait until a regular work day to send the employee for a Random alcohol tests.