It's not the trucker's fault they're traffic jammed. Does that mean it's their employer's fault?
Same here. If the truck driver was free to go home, or whatever, sure dont pay them. But traffic jams are in transit between places they are told to go. It doesn't have to be the "fault" of the employer. But the employee is captive, and working, and absolutely should be paid with regards to time.
I think you have to reason about the other side of the equation, where someone has to pay you.
It rains. I have to walk to work I the rain. I should get compensated. But is my employer on the hook, to give me the happiness I would've had if it hadn't been raining?