I’m skeptic about the terms “driverless” and “autonomous”.
“Driverless” means without driver. If we had achieved “level 5 autonomy”, our vehicles might indeed be driverless. But we are a very long way from achieving such a thing. So the companies testing their “driverless” trucks are actually testing some driver assistance technologies.
Likewise, “autonomous”, if we believe the dictionaries, means “without outside control”. If we had achieved “level 5 autonomy”, our vehicles might indeed be autonomous; but the ones being tested aren’t.
Some terms I prefer are “unmanned”, “remotely controlled”, and “using driver assistance technologies”. It depends on what you want to say really.