The U.S. Supreme Court ruled in 1990 that sobriety checkpoints are constitutional and are not illegal searches and seizures in violation of the 4th Amendment.   The reasoning was that the public’s interest outweighs the minor and temporary intrusion.  However, the Supreme Court declared that the primary purpose of the sobriety checkpoint cannot be to detect evidence of crimes or to arrest drunk drivers, but only intended to safeguard the public by preventing drunk driving. Because of this, sobriety checkpoints are classified as serving a regulatory purpose rather than a criminal purpose.