Commercial drivers of trucks with large loads have a serious job. They are responsible for long hauls across many states just to reach the destinations that they are supposed to reach. One thing that cannot be afforded is falling asleep at the wheel.
The job requires constant attention and following of all traffic laws. There are always weigh stations along the way to make sure everything is in compliance. When it comes to inspecting the drivers themselves, that is another story and it takes dot medical examiners to do it.
In order for you to become a medical examiner to the DOT standards, there is a course you will need to take. You are already a physician so you might not think that you need to take anymore courses but there are exacting standards that have to be met so you can medically certify drivers.
Commercial drivers have to pass full physical examinations on a regular basis in order to keep their certifications. It will be up to you to see if they meet all of the standards required by the DOT. Part of this is going to be drug testing but you will also be screening for other issues.
For example, if a driver has sleep apnea this is something you will need to be able to identify. With that condition, a driver could easily fall asleep behind the wheel due to the problem. Steps would need to be taken for the driver to have this health problem alleviated.
You need to be certain that all drivers meet or exceed the standards set up by the department of transportation for all reasons that are given in the guidelines. This is why you need to take the course so you can be listed on the registry as a certified DOT medical examiner.