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.
This is what CB Radios are, and many more people used to have them before cell phones.
People in mountainous areas where a cell phone is useless still do.