I know a little about because my uncle used to drive a truck, at one time he was an owner operator and then he worked for all sorts of different trucking lines. At any rate the other day I got to thinking about this when I ran across a place where you can get free online cdl training, which does not seem like that great of an idea. I suppose you could probably find a simulator that would in some ways tell you the right story, but you really are not going to learn all that you need to know. Of course once you get the CDL there is a lot of ways that you can lose it, basically you have to be perfect if you want to be able to use the thing for very long. No one is going to hire you unless they can get insurance on you and no one will insure a truck driver who does anything wrong. So you can not drink and drive, meaning not a drop and you obviously will get tested for drugs regularly.
In fact you have to think about this sort of thing all of the time, since you are not ever going to be able to act like a jerk behind the wheel either. Any sort of violation is going to make it so that the insurance company is not going to want to give you insurance or at least not at a rate that is going to make sense. If you do not have insurance you can not drive, but of course if you ever need the insurance it is pretty likely that you will not go on working either. In fact I suppose that driving long distances on the freeway will probably get to be unknown soon due to technology.