In a road movie, the characters literally drive themselves into new circumstances, and are tested by them. Their circumstances change, but their characters stay the same. Take Easy Rider: they begin in California. It's fine to have long hair in California. In fact it's entirely positive. It gets them invited into parties. They ride on motorbikes to New Orleans. In New Orleans their long hair gets them killed.
By contrast, in a rite-of-passage movie, the circumstances stay the same, and the character goes on a journey. The rite-of-passage is the plot. Change is the journey. Take American Graffiti. They drive up and down the strip in a small town discussing life, school, the future, the past. They go nowhere, the circumstances remains exactly the same, and most of the characters literally change their plans between the beginning and the end of the film.
Just something I've been thinking about. Genre tells the story.