The laws of the United States make certain allowances for when, where, and why authorities may stop motorists. Near international borders, for instance, border protection officers are permitted to set up a checkpoint and stop all motorists in the name of national security. Local law enforcement agencies will often set up checkpoints along roads to detect drunk drivers. This is most common around the holidays – such as New Year's Eve and the Fourth of July – when law enforcement knows that more people will be out drinking and driving.

Drivers often have questions about their rights when it comes to vehicle searches and seizures. More specifically, people often wonder whether or not DUI checkpoints are legal. This article provides answers to some frequently asked questions about police roadblocks and sobriety checkpoints.

Q: Which constitutional rights are triggered by checkpoints and roadblocks?

A: The Fourth Amendment to the U.S. Constitution holds that people have a right against illegal searches and seizures. Generally speaking, police are required to obtain a search warrant before conducting a search. There are, however, certain circumstances under which a police officer can conduct a legal search and seizure without a warrant, as long as it's reasonable.

Q: How is "reasonable" defined in the context of searches?

A: A search is typically viewed as reasonable if there is probable cause for law enforcement officers to believe that it's necessary. With that being said, a court will generally not consider a search or seizure that is overly burdensome or intrusive as reasonable.

Q: What are some instances in which a police officer can search your car without a warrant?

A: A police officer can legally search your car in a few instances: 1) if you consent to the search, 2) if the officer has probable cause to suspect that there is incriminating evidence in your car, and 3) if the officer reasonably believes that a search of your car is necessary for the officer's protection. An officer can also seize evidence that is in "plain view."

Q: If probable cause is necessary for a warrantless search to be considered reasonable, how can the police legally set up sobriety checkpoints?

A: In 1990, the Supreme Court of the United States decided that sobriety checkpoints did not violate the Fourth Amendment, and left it up to the states to decide whether or not they want to allow sobriety checkpoints in their state. While the Court has held that sobriety checkpoints are constitutional, it has also said that the police can't set up roadblocks for any reason.

Q: Are there states in which the police do not set up sobriety checkpoints?

A: Yes. Currently, there are twelve states in which the police do not employ the use of sobriety checkpoints.

Q: So, if the state I live in has sobriety checkpoints and I'm stopped at one, is a police officer allowed to search my car?

A: Even though your state may permit sobriety checkpoints, it doesn't mean that police officers can freely search every car they stop. In order to search your car, the police officer still must have probable cause.

Getting Legal Help

If you have been charged with a crime after being stopped at a sobriety checkpoint or other type of police roadblock, you may want to contact a local criminal defense attorney to discuss your options. For general traffic law questions, you may want to contact a traffic ticket attorney.

For more information and resources related to this topic, you can visit FindLaw's section on Traffic Laws.