This is not a positive development in many ways.
Three justices expressed concerns the ruling could open up motorists to police interference without yielding useful information about crimes.
"There is a valid and important distinction" between seizing a person to determine whether he or she has committed a crime and seizing a person to ask whether that person "has any information about an unknown person who committed a crime a week earlier," wrote Justice John Paul Stevens joined by Justices David H. Souter and Ruth Bader Ginsburg .
The case was a follow-up to a 2000 Supreme Court ruling that roadblocks intended for drug searches are an unreasonable invasion of privacy under the Constitution.