Under Minnesota law, if an officer arrests you for a DWI with probable cause, you have given implied consent to be tested for the blood alcohol content (BAC) in your system. (If the BAC registers at 0.8 or above, you are legally DWI.) Refusal to take these tests is a crime under state law.
How? By virtue of giving an officer probable cause to believe you are DWI while operating a vehicle or boat (for example, perhaps he or she believed you were driving erratically). The arrest must be made lawfully. The chemical test can be performed on your blood, breath, or urine, and it is the officer who determines which test is done. It must be done within two hours of the last time you were driving or boating.
You also give implied consent to these chemical tests–even if you have not been pulled over and arrested–if you were involved in an accident that resulted in serious injury, death or property damage.
You may also be required to take a test if the officer has probable cause to believe you may have been on drugs while driving or boating, or that drugs were involved in an accident.
Minnesota’s implied consent law also covers a preliminary breath test. The officer may ask that you take a test that, essentially, establishes probable cause. If you do not pass it, you will take the test he or she decides, as above. However, you do not have to take the preliminary test. The officer should inform you accordingly.
Be aware, however, that if the officer has probable cause that makes him or her pull you over, they can test you as described above without the preliminary test.
You also must be informed that refusal of the test is a crime under state law and that you have a right to speak to an attorney if arrested. The officer must give you a reasonable time to contact one before proceeding (roughly half an hour).