The Fourth Amendment protects citizens against unreasonable search and seizure by the government. The United States Supreme Court, in Michigan Dept. of State Police v. Sitz, found that suspicion-less roadside Operating Under the Influence (OUI) checkpoints are reasonable, and therefore legal. The Court reasoned that the brief initial investigation in a roadblock sobriety checkpoint is reasonable, because it is a minimal intrusion into the privacy of the motorist, and the public’s interest in preventing drunk driving is very high.
It’s important to know, however, that the Maine Supreme Court has found that it is unreasonable, and therefore in violation of the law, for a law enforcement officer to pull a car over simply for turning around once they see a road block and driving back in the direction they came. State v. Powell, 591 A.2d 1306 (1991). An officer may none-the-less attempt to pull someone over for this, in which case the driver must pull over immediately. Whether you are sober or impaired, OUI checkpoints in Maine can be anxiety producing. If you do not want to be stopped in an OUI checkpoint, turn your vehicle around (in a lawful manner), and proceed in the direction you were coming from. You should not be pulled over for doing this, but if you are, contact an attorney as soon as practical.