Typically, if an officer wants to stop a vehicle on the road, the 4th Amendment requires that he or she have probable cause to believe that a driver committed a crime. If, for example, the officer witnesses a driver commit a traffic violation, then they have the requisite probable cause to pull that driver over.
However, when law enforcement stops a driver at a DUI checkpoint, they don’t have any reason to believe that the driver has done anything wrong. So does their stopping of vehicles at a DUI checkpoints violate the 4th Amendment?
The U.S. Supreme Court in Michigan v. Dept. of State Police v. Sitz held that, while DUI checkpoints technically violate the 4th Amendment right against unreasonable search and seizure, the government’s interest in preventing drunk driving outweighs the relatively minor infringement on the right not to be stopped without probable cause.
The Court said, “[T]he balance of the State’s interest in preventing drunken driving, the extent to which this system can reasonably be said to advance that interest, and the degree of intrusion upon individual motorists who are briefly stopped, weighs in favor of the state program. We therefore hold that it is consistent with the Fourth Amendment.”
The California Supreme Court held in Ingersoll v. Palmer that random sobriety checkpoints are considered “administrative procedures” instead of “criminal investigations” making them more akin to agricultural checkpoints and airport screenings. The Court went on to say that there are factors which must be weighed to help determine the constitutionality of the checkpoint:
1.) The location of the checkpoint should be made at the supervisory level.
2.) The selection of vehicles stopped should be based on a neutral mathematical formula (such as every third car) rather than officer discretion.
3.) The checkpoint must be safe with proper lighting and signs.
4.) The checkpoint must be visible to oncoming motorists.
5.) The location of the checkpoint must be reasonable and in area most likely to yield DUI arrests.
6.) The time and duration of the checkpoint should minimize intrusiveness and maximize effectiveness.
7.) The length of the detention of motorists should be no longer than necessary to determine if a person is driving drunk.
8.) Law enforcement should publicize the checkpoint to minimize intrusiveness and maximize the deterrent effect of the checkpoint. In 1993, the California Supreme Court, in People v. Banks, stated that although publicity is not a requirement of checkpoints, it helps.
In addition to these factors, the Court stated that motorists who seek to avoid the checkpoint must be allowed to do so. However, most checkpoints have officers waiting nearby ready to chase down motorists who attempt to leave. Since a person is allowed to leave, the officer must observe a traffic violation to be able to pull that person over. As you can imagine, it is almost always an illegal U-turn.
Unfortunately, yes, DUI checkpoints are constitutional. See upcoming posts about what to do if you are stopped at a DUI checkpoint.