The phrase "implied consent" in the context of drunk driving refers to a Pennsylvania statute that requires everyone who operates a motor vehicle to submit to "one or more chemical tests" to determine the "alcoholic content" of their blood or the presence of a controlled substance. The law is premised on the rule that driving is a privilege and that the privilege is conditioned upon possessing a valid driver's license and, among other requirements, the implicit giving of consent to the tests specified in the statute. Because the statute can lead to an automatic driver's license suspension, every licensed driver should understand how the law operates.
If a police spots a driver whose behavior or appearance gives the officer "reasonable grounds" to believe that the person has been operating a motor vehicle under the influence of alcohol or a controlled substance, the officer can request the person to submit to a test to determine the level of intoxication. The test can be exhaling into a Breathalyzer or providing a blood or urine sample. The results of the test can be used in court if the person is charged with DUI.
A person who is requested to submit to a chemical test can refuse the request, and no sample can be taken. However, the person's driver's license will automatically be suspended for a minimum period of 12 months; if the person has prior convictions for DUI on his or her record, the suspension will be 18 months. The police officer who requests the test must inform the person of the penalty of automatic license suspension if the test is refused.
Anyone who is charged with a DUI offense, whether or not the person refused the request for a breath or blood test, should consult an attorney who specializes in defending persons against such charges. A knowledgeable criminal defense attorney can evaluate the circumstances of the arrest, the likelihood of obtaining an acquittal and an evaluation of potential penalties.
Source: Pennsylvania Statutes §547, "Chemical testing to determine amount of alcohol or controlled substance," accessed on May 11, 2015