Michigan Department of State Police v. Sitz
The Supreme Court upheld Michigan's highway sobriety checkpoints, ruling that briefly stopping every passing driver to check for signs of drunk driving does not violate the Fourth Amendment.
The decision confirms that police can use suspicionless checkpoints in limited circumstances, weighing the state's strong interest in stopping drunk driving against the brief, minimal intrusion on drivers who are not doing anything wrong.
How it got here: A Michigan trial court and the Michigan Court of Appeals ruled the checkpoint program violated the Fourth Amendment; the state sought and won Supreme Court review.
The Case in Depth
What happened
Michigan's state police created a pilot program of highway sobriety checkpoints, where officers stopped every passing vehicle briefly to check for signs of drunk driving. A group of licensed Michigan drivers who regularly used the state's roads sued before the first checkpoint even ran, seeking to block the program as an unconstitutional search and seizure.
The question before the Court
Can police set up highway checkpoints that stop every driver briefly to check for drunk driving, without any suspicion about a particular driver?
The Court's answer
Yes — the Court ruled that Michigan's sobriety checkpoints, which briefly stop every passing driver to check for signs of intoxication, are a reasonable seizure under the Fourth Amendment even without any individualized suspicion about a particular driver. It reasoned that the state's interest in curbing drunk driving is extremely serious, that the checkpoints meaningfully advance that interest, and that the brief, standardized stop imposes only a slight intrusion on law-abiding drivers.
The Court limited its ruling to the initial stop and brief questioning at the checkpoint itself. It did not decide whether any particular checkpoint was run unreasonably, or whether further detention of a specific driver for sobriety testing would still need individualized suspicion — those issues were left for another day.
Curious how the Court got there? See the step-by-step legal reasoning →
Why it matters
Drivers across the country can be stopped briefly at police-run sobriety checkpoints even if officers have no reason to suspect them individually. States gain a tool to combat drunk driving without needing individualized suspicion for each stop, while civil liberties advocates warn it opens the door to broader suspicionless stops of ordinary, law-abiding motorists.
What changes now
The case is sent back to the Michigan courts for further proceedings consistent with the Supreme Court's ruling that the checkpoint program is constitutional under the federal Constitution. The Michigan Court of Appeals had not yet addressed whether the program also violates the Michigan state constitution, so that separate state-law question remains open on remand. This is a final merits ruling on the federal Fourth Amendment issue.
What this does not decide
The Court addressed only the initial brief stop and preliminary questioning at a checkpoint, not any later, more extensive detention of a particular driver for field sobriety testing, which may still require individualized suspicion. It also did not rule on claims that a specific checkpoint was operated unreasonably, or on the separate Michigan state constitutional claim.
Concurrences and dissents
How the Justices voted
Majority (1). Justice Rehnquist (author).
Separate writings (1). Justice Blackmun (author of a concurrence).
Dissent (2). Justice Brennan (author).
Concurrence — Justice Blackmun
Justice Blackmun agreed only with the outcome, not the majority's full reasoning. He used his brief concurrence mainly to note that he had been warning about the toll of highway deaths for two decades, since his 1971 opinion in Perez v. Campbell, and expressed satisfaction that the Court was now emphasizing that tragedy. Read the full concurrence →
Dissent — Justice Brennan
“Some level of individualized suspicion is a core component of the protection the Fourth Amendment provides against arbitrary government action.”Brennan's objection to allowing suspicionless stops without proof that suspicion-based stops were impractical.
Justice Brennan argued the majority misapplied the balancing test by undervaluing the intrusion on drivers and overstating the checkpoints' law-enforcement benefit. He stressed that suspicionless seizures are usually only allowed when the government proves individualized suspicion is impractical, as in immigration checkpoints, and that Michigan made no such showing for drunk-driving stops. He would have required at least some level of individualized suspicion. Read the full dissent →
Dissent — Justice Stevens
Justice Stevens argued the checkpoints were more like unconstitutional surprise stops than the fixed, predictable immigration checkpoints in Martinez-Fuerte, because sobriety checkpoints rely on surprise, occur at night, and give officers wide discretion over who to detain further. He also argued the record showed checkpoints produced no proven net increase in arrests or safety over ordinary patrols, so the state failed to show the seizures actually advanced its interest. Read the full dissent →
How the Court got there
The legal reasoning, step by step
- The Court applied the three-factor balancing test from Brown v. Texas for seizures less intrusive than an arrest, weighing the gravity of the public concern, how much the seizure actually advances that interest, and the severity of the interference with individual liberty.
- The Court found the state's interest in stopping drunk driving to be very strong, pointing to tens of thousands of alcohol-related highway deaths each year as an undisputed and grave public safety problem.
- On intrusion, the Court held that the 'fear and surprise' that matters is the concern felt by law-abiding drivers seeing a visible, uniform checkpoint stop every car — not the anxiety of a driver who has been drinking — and found that kind of intrusion slight, comparable to the immigration checkpoints approved in United States v. Martinez-Fuerte.
- On effectiveness, the Court held that courts should not second-guess the choice among reasonable law-enforcement methods, since that choice belongs to politically accountable officials who understand limited police resources; it found the 1.6% arrest rate at the one Michigan checkpoint comparable to the ratio the Court had already approved for immigration checkpoints in Martinez-Fuerte.
- Balancing these factors together, the Court concluded that the state's strong interest, the checkpoint's contribution to that interest, and the brief, minimal intrusion on drivers tipped in favor of allowing the program to proceed.
Doctrinal impact
Cases affected by this decision
Reaffirms Martinez-Fuerte (428 U. S. 543)
The Court relied on its earlier approval of suspicionless immigration checkpoints as the closest precedent supporting sobriety checkpoints.
Distinguishes Delaware v. Prouse (440 U. S. 648)
The Court said this case, which struck down random individual stops for licenses, did not control because sobriety checkpoints are not random or standardless.