Even if the interview went exceptionally well, applicant beware! If the person interviewing you offers to walk you to your car, they may have ulterior motives to basic courtesy. If your car is a mess, your potential employer may make a determination about your future work habits. Also, your car may be saying too much! Personal information does not belong in an interview or on a resume.
In the suburbs, your mode of transportation is an extension of that interview. Remove the car seats, toys, and activity/political/religious magnets that provide your employer with too much information that could be detrimental to your candidacy.