Hitchhiking stands for relying on the kindness of strangers to get where you are going. Dream books read it as trust, risk and a wish for help you have not asked for openly.
When this appeared in your dream, what were you feeling?
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.