Anytime your moving and your involved in an accident.
You are a CDL holder which makes you a professional driver.
Even if someone else is totally the fault of the beginning of any accident,and you as the professional didn't make every effort to avoid being involved you to will share the blame,and it will be ruled preventable.
Now when the investigation is complete,and its ruled you did everything you could to not be involved,all of the blame will rest on the one who caused it.
But this is a very rare case.
If you are parked some place out of harms way with the motor off,and someone hits you thats a non-preventable.
But if your in anyway empeading the flow of traffic,on the side of a roadway,commercial driveway,or parking lot,then this is a preventable accident.
Heres what is my qualifications for my post statements.
I'm well into my 44th year as a LTL city driver,and also a certified UPS Freight safety trainer.
I'm not a cop,but for all of my experience I believe I'm right with this post reply to your question.
I don't know about Old Dominions policies,but this is the general rule regarding professional drivers.