Vehicles that you ride in usually reflect two things; the direction you are heading in life, and your body. (the thing you travel or “ride” through life in) This might vary if you are a mechanic or designer of vehicles. Unusually over exposure to a specific vehicle type may easily change the meaning.
The condition of the vehicle might give you an idea of your health. Driving an old beat up car down a muddy road on a stormy night would be considered a pretty bad dream! However flying a Lear jet through blue skies with a song in your heart and the wind at your tail would be a rather good dream. :)