I was watching this video of a live chicken trapped on a moving truck and thought it was strange that it’s not possible to say anything to them even when circumstances might warrant it. All we got is honking and waving. There could be a touchscreen interface with a map of nearby vehicles. It could be voice controllable or the passenger could do it for safety.
I used to have a cat that loved to jump up under any truck that would be delivering something. We used to tell them not to leave until we had eyes on our cat. Even with that, he was such a varmint that I’d give them my business card, and tell them that if they got to their next delivery, and found him in their truck, to call me, and I’ll come get him.
Luckily, our precautions worked, but he was a troublemaker.