If you are over 21, the expressed consent laws state that you have the right to request a breath or blood test. The police officer must comply with your decision within two hours. DO NOT let any officer pressure or coerce you into changing your mind. It is their duty and responsibility to follow your decision, regardless of how busy they are and/or inconvenient the request may be. Only under extraordinary circumstances can the officer force you to change your mind.
Of course, no one can force you to provide a sample of your breath and/or blood (unless serious bodily injury or a death is involved). Although, a refusal will become part of the prosecutor’s case against you. If you refuse to take the test, or provide an incomplete test, it can later be introduced to a judge or jury and used as evidence that you were drunk. This means that the prosecutor can argue that you did not take the test because you were drunk!