Supreme Court decisions

Several years ago, I had this argument with a fellow criminal justice faculty member at my old college in Massachusetts. I am a defense attorney. He was the local chief of police and an attorney, as well. The discussion focused on this statement:
You have significant protections against unreasonable search and seizure in your home; however, those rights are reduced when you walk down the street and are nearly eliminated when you are in a car.
We debated the issue and reached an agreement on the issues involved (how often do you find a defense attorney and police chief in agreement?).
Consider how your rights against search & seizure vary in your home, walking down the street, and in a car. It may be helpful to make up a scenario for each one of these to test our your analysis.
Do you agree with the statement above? How would you prepare to argue this issue if we were in class? Citing two cases from the text (or Supreme Court decisions if you choose to read cases outside of the text) for each of 1) in your home, 2) walking on the street, and 3) driving / riding in a car, prepare your argument on this issue.