Holiday season often means checkpoint time, so let's review the legal principles that may apply. Most vehicle stops are directed at particular vehicles, based on reasonable suspicion of violations of the law by particular occupants. Checkpoint stops are different-multiple vehicles are stopped one after the other, at the same place, without any suspicion beforehand that anyone in particular may be engaged in unlawful activity.

To justify this kind of wholesale detention under the Fourth Amendment requires both a compelling purpose and strict compliance with procedures that confine police activity to the accomplishment of that purpose. To date, the U.S. Supreme Court has indicated constitutional approval for only five kinds of checkpoints and has expressly rejected another.

Drivers License Checkpoints

In Delaware v. Prouse, a patrol officer made random vehicle stops along the highway to see whether drivers were licensed. The Supreme Court ruled that such stops violate the Fourth Amendment because they single out individuals for detention without any particularized suspicion of wrongdoing. In so ruling, however, the court commented that agencies could "develop methods for spot checks" if a neutral formula were used to determine which cars were stopped, rather than leaving this decision to the discretion of individual officers. For example, if officers stopped every vehicle, or every other vehicle, merely asked to see license and registration documents, and allowed licensed drivers to proceed after a very brief detention, the Fourth Amendment would not be violated.

The court gave its approval of such a stop in a narcotics case stemming from the plain-view seizure of drugs at a license checkpoint in Texas v. Brown. Clifford Brown was stopped around midnight by officers of the Ft. Worth Police Department, conducting "a routine driver's license checkpoint." During the stop, officers saw balloons of heroin in plain view in the car and, after arresting Brown, they found even more drugs and paraphernalia during an impound
inventory.

On Brown's appeal from his conviction, neither he nor the court made an issue of the validity of the initial stop, focusing instead on application of the "plain view" doctrine. Upholding Brown's conviction, the Supreme Court noted that the state courts "did not question the validity of the officer's initial stop of appellant's vehicle as a part of a license check, and we agree." (Texas v. Brown)

Sobriety Checkpoints

Michigan State Police established a highway sobriety checkpoint at which every vehicle was stopped to see if drivers showed apparent signs of intoxication. If not, they went on their way (usually in 25 seconds or less); if they appeared impaired, they would be directed to the side for further investigation. Rick Sitz and other motorists challenged the legality of the checkpoints.

Examining the state's compelling need for sobriety checkpoints, the Supreme Court looked to statistics on deaths, injuries, and property damage caused by intoxicated drivers and said, "No one can seriously dispute the magnitude of the drunken driving problem or the States' interest in eradicating it." Balanced against the minimal intrusion on motorists passing through the checkpoints, the Supreme Court had no difficulty in finding that public safety concerns justified the brief detentions.

The court noted that checkpoint locations were chosen under predetermined guidelines, uniformed officers stopped every approaching vehicle, stops were very brief and police activity was limited to the detection of impairment (unless evidence of other wrongdoing appeared), and two of 126 questioned drivers were arrested for driving under the influence. The court held that the operation of the sobriety checkpoint in this case was "consistent with the Fourth Amendment." (Michigan v. Sitz)

Witness Checkpoints

One case, Illinois v. Lidster, concerned the constitutionality of setting up a checkpoint to try to locate witnesses to a recent, serious crime. An elderly bicyclist was killed by a hit-and-run driver just after midnight on a Saturday on a particular roadway. One week later, at the same place and time, officers set up a "witness checkpoint" to pass out fliers requesting information from potential witnesses who might be repeating the route from a week earlier, and might have seen something. Robert Lidster drove up to the checkpoint under the influence of alcohol and was arrested at the scene. He moved to suppress the evidence of his impairment on the ground that the checkpoint stop was unlawful.

The Supreme Court applied the same kind of balancing test it had used in Brown and Sitz, and found the checkpoint justifiable. The court said that the concept of criminal suspicion was inapplicable to an effort to get the public's assistance in an investigation of an earlier crime: "The stop's primary law enforcement purpose was not to determine whether a vehicle's occupants were committing a crime, but to ask vehicle occupants, as members of the public, for their help in providing information about a crime in all likelihood committed by others." (Illinois v. Lidster)

Border Checkpoints

Immigration officials operating near our international borders are not allowed to make random stops of vehicles, except based on reasonable suspicion that a particular vehicle or occupant may be breaking the law. (Almeida-Sanchez v. U.S.) But the operation of fixed checkpoints at or near the border is allowable when conducted with the same kinds of features used in other checkpoints, including signs alerting the public to the purpose of the checkpoint, a neutral formula for deciding which vehicles will be stopped, use of lighting and uniformed officers to reduce motorists' anxiety, and release after brief screening, unless initial observations justify referral for secondary screening. If such guidelines are followed, said the Supreme Court, "Stops routinely conducted at permanent checkpoints are consistent with the Fourth Amendment and need not be authorized by warrant." (U.S. v. Martinez-Fuerte)

Roadblocks

In Indianapolis v. Edmond, the Supreme Court rejected the use of checkpoints solely for the purpose of trying to catch drug traffickers. The court thought a checkpoint that allowed an opportunity for a K-9 sniff of every stopped vehicle was an unjustifiable intrusion on liberty and privacy interests, and unlike the sobriety checkpoints approved in Sitz, was not aimed at enhancing public safety by removing dangerous drivers from the roads. The court's reasoning was expressed as follows:

"We have never approved a checkpoint program whose primary purpose was to detect evidence of ordinary criminal wrongdoing. Rather, our checkpoint cases have recognized only limited exceptions to the general rule that a seizure must be accompanied by some measure of individualized suspicion." (Indianapolis v. Edmond)

The court was careful to add, however, that traditional roadblocks erected to nab escaping criminals or those thought to pose an imminent threat to public safety would not be invalidated by the Edmond ruling. Said the court, "The Fourth Amendment would almost certainly permit an appropriately tailored roadblock set up to thwart an imminent terrorist attack or to catch a dangerous criminal who is likely to flee by way of a particular route."

Devallis Rutledge is a former police officer and veteran prosecutor who currently serves as special counsel to the Los Angeles County district attorney. He is the author of 12 books, including "Investigative Constitutional Law."

Checkpoint Protocol

• To date, checkpoints have been approved to check for driver's licenses, sobriety, witnesses to a recent serious crime, and immigration compliance. Approval has also been suggested for targeted roadblocks.

• Checkpoints are not allowable to interdict narcotics transportation.

• Neutral selection and standardized criteria must be followed for all checkpoints.