You will have to face certain Mississippi drunk driving penalties if you are found to be driving under influence of alcohol with a BAC level of 0.8 or higher. For commercial drivers, the BAC limit is 0.04, and for under-21 drivers, it is 0.2. It is also important to note that when you are stopped by a traffic official under the suspicion of drunk driving and are asked to take a chemical test to determine the BAC level, you must not refuse. Refusal to take the test will attract an immediate license suspension for a period of ninety days. This penalty will remain intact even if the charges against you get dismissed in the courtroom.