Roadblocks and checkpoints are often used by municipal, county, and state law enforcement divisions to make temporary stops of vehicles. These stops are made for a variety of reasons: checking the validity of drivers' licenses and registration, determining if the vehicle meets safety inspection minimums, deciding if the car has the necessary municipal parking permit, etc. Probably the most common purpose is to find and apprehend intoxicated drivers.
What is at issue in these scenarios? Checkpoints involve a constitutional detention, a seizure of a person, without any level of particularly individualized doubt, i.e., "reasonable suspicion" or "probable cause." Because there is no focused suspicion on an individual, rather than assessing the existence or absence of probable cause or reasonable suspicion, when the use of a roadblock is challenged, courts will examine police conduct and the circumstances of the stop and determine if the checkpoint is a reasonable intrusion, and therefore justifiable, under the Fourth Amendment to the Constitution. In the context of sobriety checkpoints, this reasonableness determination involves an analysis of three factors:
- the magnitude of a state's interest in preventing accidents caused by intoxicated drivers,
- the extent to which the checkpoint advances that goal, and
- the measure of intrusion on an individual's privacy, both objectively, as perceived by the reviewing court, and subjectively, as the motorist may perceive the intrusion.
The U.S. Supreme Court applied these factors to determine the constitutionality of a sobriety checkpoint in the landmark 1990 case of Michigan Department of State Police v. Sitz. Here, Michigan implemented a program where checkpoints would be set up at predetermined sites along state roads. All drivers passing through would be stopped and checked for obvious signs of intoxication. If such indications were detected, the motorist would be taken out of the flow of traffic and an officer would check his or her license and registration. If warranted, the officer would conduct field sobriety tests. All other motorists would continue unimpeded after the initial screening. The check lasted 75 minutes, during which 126 vehicles passed through. The average delay was 25 seconds. Three motorists were detained on suspicion of intoxication, and two were arrested. The Court held that this checkpoint passed constitutional muster. Citing the aforementioned factors, the Court found that:
- Michigan had a substantial interest in eliminating drunken driving, noting that "no one can seriously dispute the magnitude of the drunken driving problem [or the] State's interest in eradicating it."
- This checkpoint advanced the State's interest in curbing the drunk driving problem, noting that the use of a permissible checkpoint is but one of many reasonable alternatives to remedying the problem, and "the choice among such reasonable alternatives remains with the governmental officials who have a unique understanding" of the problem and the resources available to combat it.
- The intrusion, both objective and subjective, was slight, pointing out the brevity (25 seconds) of the average encounter. The Court also noted that any subjective intrusion, such as making a motorist fearful or annoyed, was diminished by the fact that motorists could plainly see all vehicles were being stopped.
Officers should keep these constitutional principles in mind when planning and implementing roadblocks and checkpoints. Any evidence found during a stop at an improper roadblock or checkpoint is subject to suppression at trial. Officers should also be aware that several states place additional requirements and restrictions on roadblocks, or even completely disallow them under state law. Consult with the appropriate legal counsel for your department to learn more.