To dream that you ride in an automobile, denotes that you will be restless under pleasant conditions, and will make a change in your affairs. There is grave danger of impolitic conduct intimated through a dream of this nature.
If one breaks down with you, the enjoyment of a pleasure will not extend to the heights you contemplate.
To find yourself escaping from the path of one, signifies that you will do well to avoid some rival as much as you can honestly allow.
For a young woman to look for one, she will be disappointed in her aims to entice some one into her favor. ... Ten Thousand Dream Interpretation
To dream that you want an automobile stresses a desire for financial gain.
The motion of an automobile is associated with physical potency that is relative to sexual tension, hence dreams of actual driving, speeding, or skidding may be classed as sexual desires. Being in a wrecked car or escaping from one may warn you of a rival interest or an impending complication of events. Generally, the automobile like the airplane is an expression of the dreamer’s desire to motivate a plan.... Psycho Dream Interpretation
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. :)... Encyclopedia of Dreams