The short answer is no, you are not required to take a breathalyzer test or perform field sobriety tests if you are pulled over by the police on suspicion of drunk driving. The only thing that you must do is give the officer your license and registration when asked. Your refusal to perform field sobriety tests or to take a breathalyzer test cannot be used as evidence against you during your trial, but there are other consequences if you refuse to perform these tests. Some factors to think about in deciding whether or not to take these tests are discussed below.
Field Sobriety Tests: These tests can vary depending upon the officer who gives them to you, but can include: the nine step walk and turn, one-legged stand, reciting the alphabet, and the horizontal gaze nystagmus test. These tests can be difficult to perform even under the best of circumstances. Think about factors other than alcohol that may impair your ability to successfully perform these tests. For instance, wearing high heels, being overweight, having a bad back, fatigue, poor weather and road conditions can all lead to difficulty in performing these tests. I have seen police officers fail these tests when asked to demonstrate them, so please do not underestimate their difficulty. If you elect not to perform field sobriety tests, you will most likely be arrested for OUI ("Operating Under the Influence"), but the case against you will be more difficult for the prosecution to prove in Court because you have given them less evidence to use.
Breathalyzer Tests: Under Melanie's Law you will lose your license for 180 days for refusing to take a breathalyzer (unless you have a prior conviction(s) for OUI, or are under the age of 21 which will lead to a greater time period for the loss of license). If you do take the breathalyzer and blow a .08 or higher, you will also lose your license (until the disposition of the case, but not greater than 30 days) and the prosecution can introduce the breathalyzer results as per-se evidence of your impairment while operating your car. (A conviction will lead to further loss of license.)
The decision to take or refuse these tests is yours, make it wisely. Think about the consequences of taking these tests and remember that if you are charged with OUI, the prosecution does not have to prove that you were "drunk", just that your ability to drive the car was impaired by alcohol. Even if you do not feel that you are "drunk," you may fail either or both of these types of tests if you have been drinking.