Thirty-eight states (which do not include Minnesota based upon our state Constitution - see Ascher v. Comm. of Public Safety, 519 N.W.2d 183 (1994); Gray v. Comm. of Public Safety, 519 N.W.2d 187 (1994)) allow DUI checkpoints. A checkpoint is basically a roadblock where the police stop and check each driver's license while at the same time seeing if they notice any signs of intoxication (watery, bloodshot eyes, smell alcohol, slurred speech, open bottle violation, see or smell drugs...) as the driver passes through the roadblock. The U.S. Supreme Court ruled in 1990 that DUI checkpoints are not a violation of a person's 4th amendment right to be free from unreasonable searches and seizures. The court found that the roadblock is a seizure where drivers are detained for a brief period of time. But, it also found that the state has a "grave and legitimate interest" in protecting the public from drunk drivers. Applying a balancing test of these competing interests, the court determined the limitation on each driver's freedom was constitutional given the stronger governmental interests in the use of the checkpoint.