In 1990, the U.S. Supreme Court made a ruling that would allow officers to establish sobriety checkpoints across the United States provided they acknowledged certain guidelines such as publicizing the locations of these checkpoints across the state.
But why did the U.S. Supreme court make this ruling in the first place?
Many people in Michigan don't realize that prior to 1990, officers were not required to announce DUI checkpoints and thereby could arrest anyone suspected of drunk driving during the stops. A Michigan appeals court ruled however that these DUI checkpoints violated a person's Fourth Amendment right. The U.S. Supreme Court overruled, "using a balancing act to determine that the dangers posed by drunk driving outweighed the Fourth Amendment intrusion."
Now, according to police, if a person is driving, an officer needs a reason to pull them over. If an officer does not have a reason, the stop can be considered illegal. A person's Fourth Amendment right protects a citizen from unreasonable searches and seizures. By announcing the checkpoints, officers are announcing their reason for stopping someone so as to avoid any complications when enforcing drunk driving law.
So what does this mean for drivers?
"If [police] don't announce [checkpoints] they would definitely be in trouble and they wouldn't be able to use any of the results," says one defense lawyer. It is the hope of police officers in Michigan that by publically announcing check points, it may deter people from drinking and driving in the first place. And especially with the holiday season upon us and with so many people on the roads, officers say it can also remind people of how important driver safety can be.
Source: The Valley Independent Sentinel, "Why Do Police Announce DUI Checkpoints?" Ethan Fry, Nov. 20, 2012