Police often uses checkpoints, especially in the summer months, to identify and arrest individuals on the suspicion of driving under the influence (DUI). Federal and state law, however distinguish police checkpoints used for DUIs and those used for drug interdiction.
Interdiction is a term which refers to law enforcement’s efforts to stop the sale or distribution of illegal drugs. While there is obviously a public interest in preventing DUI and the sale of drugs, the two areas are treated differently. The United States Supreme Court in Michigan v. Sitz found that checkpoints used for the primary purpose of identifying intoxicated individuals are constitutional. The Court reasoned that highway safety poses an immediate safety risk to the public and the minor intrusion of the checkpoint met the Fourth Amendment reasonableness standard. The Court further ruled that crime prevention was not the purpose of the stop but rather focused on the public safety aspect of it.
This ruling caused the Court to distinguish sobriety checkpoints and those set up primarily to fight the war on drugs. In City of Indianapolis v. Edmond the Supreme Court found that drug checkpoints were unconstitutional because criminal investigation not public safety was the purpose of the police action. The court found that there are other ways to investigate crimes other than setting up checkpoints. There is a grey area when police attempt to use drug interdiction tactics during DUI sobriety checkpoints.
The Court in Illinois v. Caballes found a checkpoint constitutional when police used drug sniffing dogs during you a DUI stop. The Court held that the dogs did not extend the otherwise lawful action for the DUI issue.
In Pennsylvania, random stops of vehicles at a checkpoint are unconstitutional. Police and State Troopers, however, are permitted to set up checkpoints if they provides public notice and the checkpoint is established in an area where the Commonwealth can demonstrate, statistically, that the roadway is traveled by intoxicated drivers.
If you are stopped at a checkpoint you should cooperate with police but never consent to a search of your car, your person, or provide any statements to police without an attorney present. While the police will more than likely arrest you, following these simple rules will provide your attorney with possible defenses. These defense could lead to a dismissal of charges and your acquittal.