American cars & Czech physicists.

Two completely unrelated questions:

1) What would be a good estimate for the number of cars the average American sees on a typical day? I'm talking middle-class suburbanite on the way to work and back during rush hour. I understand this is vague, but all I need is a realistic estimate.

2) I'm writing about a Czech physicist who moves to America à la the German Wernher von Braun at about the turn of the century (by which I mean 2000, sorry) to work for the government on top-secret astrophysics technology. What would life be like for him? Where would he live? Are displaced scientists allowed to interact with Americans, marry them, raise families? What sort of ties would he be allowed to keep with his home country? What sort of ties would he be forced to make?

Thank you very much in advance. I know these are rather odd questions; but again, aren't most? :D