You may just be trying to get home after a long day at work. You did stop off to enjoy a drink or two with friends or family, but you made sure you were okay to drive before leaving. So, you may be surprised to see flashing lights in your rear-view mirror.
You pull over and wait for the officer to come to the window. Your first inclination is to defend yourself, but you may want to think again. Other than answering basic questions about your identification, you may want to take advantage of your right to remain silent.
But...you haven't been read your Miranda rights
You always have your Constitutional rights. The reading of the Miranda warning does not trigger them. From the moment you have contact with a government agency, you may invoke your rights. Law enforcement officers fall into this category. You do have to answer any questions that may incriminate you. It doesn't matter whether the officer places you under arrest and reads you your rights.
If you do answer questions, you could provide the officer with the probable cause needed to arrest you. You could also provide statements that the prosecutor may attempt to admit to the court. You have no obligation to make the jobs of the officer or the prosecutor any easier.
But...you have to do it right
In order to make it clear that you are invoking your Constitutional right to remain silent, you must speak up. The U.S. Supreme Court ruled that simply remaining quiet isn't enough. You also want to make sure that you don't use vague language. You need to remain calm and polite, but you can assertively let the officer know that you do not want to answer any questions and that you will remain silent. You may also exercise your right to an attorney at this point.
You do not have to use any magic words to invoke your rights, but you do need to make it clear. The test is whether a reasonable police officer would understand that you invoked your right to remain silent. For this reason, you cannot be vague in the language you use. The officer may tell you that it makes you look guilty to take advantage of your rights, but that may just be a tactic to get you to talk.
Be careful not to start answering questions later without your attorney present or without the advice of an attorney. Police will not remind you that you invoked your right to remain silent. It's up to you to protect your rights.