This link here should be of some help:

DOT Rule 49 CFR Part 40 Section 40.197 | Department of Transportation
Burnt Toast Reviewed by Burnt Toast on . What if a sole propietor gets a negative dilute result? Here the story: I have my own company that must deal with DOT regulations. I am the owner and only driver, so I'm my own boss. Every couple of years, I have to take a DMV physical, which includes a drug test. I have no problem with that--I'm only an occasional smoker, healthy, exercise, etc. I can stay clean long enough to pass a test that I set up for myself. The other time I have to test is when I get called for a random test from my drug group. I had to join a group, as do all Rating: 5