YES! Sorry this is such a simple post, but I sometimes get surprised talking to people at what they don't know about police stops. I want you to think about this- if you and a friend were pulled over, and an officer saw something illegal in the car, do you not think they could separate you and then tell each of you, "well your buddy over there just said it was all yours" or "look, the more honest with me you are, the easier this will go on you?" This is the police doing their job, getting you to give them free information while you are not yet in custody. And regardless of how you feel about police lying to get information, it is A-OK in the eyes of the law.
As of June 1st, you may no longer assert your right to be silent by merely doing just that, remaining silent. Sound confusing? Not to the Supreme Court of the United States. According to a recent decision, a suspect in a criminal case must unambiguously communicate to their questioner that they intend to invoke their right not to cooperate. Berghuis v. Thompkins (#08-1470) . The decision means that once a suspect is in custody, officers must still issue Miranda warnings and be convinced that the subject understands them. However, once officers begin asking questions a person must explicitly tell the officers that he wants to remain silent. Otherwise, any response the person makes is deemed potentially admissible.