Vehicles usually symbolizes our passage through the journey of life. The way that you travel through your life's journey, and your effectiveness in controlling your life.
The type of vehicle will give indications of the type of experience being related in the dream message. For instance, an ambulance will indicate a need for healing in the giving and receiving of experience, a police car will signify the need for discipline in experiences, an old car might suggest old habits, or 'things the way they used to be' or the need to change the old way of doing things...etc.
A Silver Jeep Commander is a powerful vehicle with the ability to go pretty much wherever you want to go. It suggests you feel you can accomplish just about anything you set your mind to.
Silver symbolizes something of value with regard to your personal development. May symbolize the feminine (silver has associations with the moon) which would represent intuition; or the subconscious.

Yellow - a happy and encouraging color. But it can easily turn into unpleasantness. It is the color of intuition, premonition, and perceptions.
Warm yellow is the color of the radiant energy of the sun; it is a symbol of optimism, joy and spirit.
An unpleasant shade of yellow stands for irritation, envy, extroversion, extreme motivation and activity.

Black - the color of the subconscious, of sinking into the darkness, or mourning. Black is masculine; it is the color of night. Black stands for limitation, hidden things, despair, depression, things that are considered 'taboo', conservatism, old age, melancholy and sacrifice(the giving up of things to make you, or someone else happy), your shadow (an aspect of your personality that is hidden, unknown and/or repressed within your subconscious mind).

The number 7 - the cycles of life, ie: 7, 14, 21, etc., a week,  transcendent meanings; 7 candles, 7 churches, 7 chakras, 7 colors of the rainbow, 7 notes of the scale, and so represents investigation into human wholeness, or seeking complete oneself.

Grocery store - suggests that you are emotionally and mentally strained. Alternatively, you may be brainstorming for new ideas or looking for the various choices out there for you. What is feeding you? What are you lacking?

Strangers - If the person reminds you of someone you know.. think about your relationship with him or her, and the issues that the dream has brought up, or how you relate to the person that is being represented. If these people are totally unrecognizable (they don't remind you of anyone you know)... they would represent different, and unknown, aspects of yourself. They are extensions and projections of your own subconscious, and personality. Alternately, a stranger may represent an unknown fear, or danger, you feel in your waking life.

Human beings (male and female alike), are curious, questioning, and have a need for information, and spiritual expansion. We all have masculine and feminine aspects (or sides) to our subconscious.
The masculine aspects would be the part of ourselves that we view as brave, strong, stubbornness, authoritative, logical...etc.
The feminine aspects would be the part of ourselves that we view as emotional, nurturing, tender, yielding, sensitive...etc.
When we dream, all the different parts of our 'inner selves' interact, and 'come alive', as though they were different people.
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Have you recently started a new project or career?
Are you looking for new and innovative ways to improve your life?
Have you recently met someone that has piqued your interest?
Have you been feeling bold and confident in yourself lately?
Have you had an inspiring idea, or have you been offered a great opportunity?
Have you been thinking of giving up something for your own self-improvement?

It seems as though you have a positive outlook for yourself and your future. The sky's the limit!
Reach for that brass ring, and good luck!!