People interact with other drivers while on the road, it's just a different type of communication. I think some element of feeling "removed" from the situation compared to a face-to-face encounter has an effect in our interactions.

I remember reading about a study that found people were more ethical (IIRC, less likely to cheat on a quiz) if there was a pair of eyes in their visual field. Not even real eyes, just a photo.

Every time I’m berated while playing Xbox I wonder if eye contact, or even perceived eye contact, does something to our brains that makes us behave more in accordance with social norms.