80s or 90s road thriller movie

I have been looking for a long time: Unfortunately I don't remember much, 80s or 90s movie, it takes place in a desert environment, a long asphalt road, some kind of road movie. (Thriller or Horror movie) In the beginning of the movie a young couple travels and stop in the desert for sex on the side of the road. The girl is shown in a riding pose, no clothes on.