The passenger who disappears from the car is read as a visitor from the past riding along for a while. Dream books see it as a memory or influence that travels with you and then quietly lets go.
Does the traditional reading fit your dream, or did it mean something else to you?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.