In most jurisdictions, states have adopted what are called "implied consent" laws. These laws state that a person who receives a driver's license gives their "implied consent" under certain circumstances to the taking of a chemical test for intoxication to determine if they have been driving while intoxicated. Generally, however, you can still refuse to perform field sobriety tests or a request to submit to a breath or blood test. But, there may be consequences, for this refusal. For example in Louisiana the first time a person refuses to submit to a breath alcohol test when the officer has probable cause to believe he or she is driving while intoxicated results in an automatic 180 day suspension of driving privileges. Successive refusals result in longer suspensions.

Many states have similar laws. There are also limited circumstances, such as being involved in an automobile accident involving injury or death, where the police may be able to obtain a blood sample even if you do not consent. It is best not to engage the officer in conversation beyond what is necessary to identify yourself and provide your driver license, registration and insurance papers. Likewise it is usually better to refuse to perform field sobriety tests that the officer might ask you to perform. The officer will engage you in conversation and ask you to perform tests so he can gain evidence that he will use to justify your arrest and illustrate the effects of alcohol on your ability to control a vehicle at the time you were stopped. There are a number of these types of tests, which a police officer might ask you to perform at the scene and again at the police station. Oftentimes, this will be videotaped, and shown at trial.

You should protect your rights by calmly but firmly refusing to take the field sobriety test and refusing to answer questions about your consumption of alcohol. The police have no evidence of blood alcohol of a person whom they have stopped for a DWI unless the person takes a breath or blood test. While your refusal to submit to any and all of these tests may be offered as evidence against you at trial, it is much weaker evidence than the evidence that the police officer might obtain through your submission to these tests.