From Foundation for Economic Education:

Lars Trautman, a senior fellow of criminal justice and civil liberties policy at the R Street Institute, told me via email:

[Michigan v Sitz] created a perverse result in which a suspicionless stop that would be constitutionally offensive if conducted against an individual suddenly becomes sound so long as it’s done against a random group of people. The purpose of the 4th Amendment was to limit seizures, not to create incentives to do more of them.

Essentially, Trautman believes it’s a violation of the Fourth Amendment to pull over large numbers of American drivers without a reasonable suspicion that they were doing anything wrong.

In spite of criticisms and efforts to roll them back, checkpoints remain widespread because police departments say they’re an effective deterrent to drunk driving.