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Police Roadblocks and Sobriety Checkpoints FAQ

The law makes certain allowances for when, where, and why authorities may stop motorists at designated roadblocks and checkpoints. Some of these allowances include:

  • National security: Near international borders, border protection officers can set up a checkpoint and conduct traffic stops to prevent undocumented immigrant trafficking.
  • Drunk driving and public safety: Local police departments often set up checkpoints to detect impaired drivers. This is most common around certain holidays – such as New Year's Eve and the Fourth of July – when more people are likely to be drinking and driving.

Drivers often have questions about their rights regarding vehicle searches and seizures. You may also wonder if DUI checkpoints are legal in your state.

This article answers some frequently asked questions about police roadblocks and sobriety checkpoints.

What are the parameters for a legal police roadblock?

The legality of the roadblock depends on its primary purpose. There has to be a specific circumstance that justifies the intrusion of motorists' expectation of privacy.

This means that law enforcement agencies can't set up roadblocks simply to assist in the normal process of law enforcement. For example, if a roadblock's primary purpose is to check for illegal drugs as a method of general crime control, that could be considered in violation of the Fourth Amendment.

However, public safety is a valid primary purpose. This is why sobriety checkpoints that assess for dangerous drunk drivers are more likely to be in line with the Fourth Amendment.

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

The Fourth Amendment to the U.S. Constitution holds that you have a right against illegal searches and seizures.

Generally, law enforcement officers are required to obtain a search warrant before conducting a search. However, there are circumstances when a police officer can conduct a legal search and seizure without a warrant, as long as it's not an unreasonable search.

A search is typically reasonable if there is probable cause for law enforcement to believe it's necessary. A court will generally not consider an overly burdensome or intrusive search or seizure as reasonable.

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

A police officer can legally search your car in a few instances. These instances include:

  • If you consent to the search
  • If the officer has probable cause to suspect that there is incriminating evidence in your car
  • 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.

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

In 1990, the U.S. Supreme Court of the United States decided that sobriety checkpoints did not violate the Fourth Amendment. It left it up to the states to decide whether 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 just any reason.

Are there states where the police do not set up sobriety checkpoints?

Yes. Currently, there are 12 states that do not permit sobriety checkpoints.

There are differences in how police roadblocks are conducted and regulated across states. This is because the interpretation and application of state constitutions can vary from one state to another. Some states offer more protection against unreasonable searches and seizures than the federal Constitution. Some offer less protection and allow more flexibility for law enforcement.

Regardless, law enforcement agencies must operate within the bounds of both federal and state constitutional law.

If I am stopped at a sobriety checkpoint, is a police officer allowed to search my car?

Even if your state permits sobriety checkpoints, it doesn't mean that police officers can freely search every car they stop. To search your car, the police officer still must have probable cause. This means that to legally search your car, an officer must have reasonable grounds to believe one of more of the following:

  • A crime has been committed
  • A crime is being committed
  • Evidence of criminal activity can be found in your vehicle

What can I expect at a sobriety checkpoint?

Not every vehicle is stopped at these checkpoints. Officers stop vehicles at random intervals, such as every tenth car, to identify potential drunk drivers. Law enforcement will look for signs of intoxication, including:

  • Slurred speech
  • Bloodshot or glassy eyes
  • The odor of alcohol or marijuana
  • Visible open containers
  • Impaired motor skills, like trouble rolling down a window or handing over a driver's license and proof of insurance
  • Erratic driving

If any of these signs are present, an officer may have reasonable suspicion to administer field sobriety or breathalyzer tests.

If you fail a field sobriety test or your blood alcohol content (BAC) is above your state's legal limit, you could be cited for DUI (Driving Under the Influence) or DWI (Driving While Intoxicated).

If you are arrested for DUI or DWI at a sobriety checkpoint, you have the right to remain silent and to have an attorney present during questioning. You should be informed of these constitutional rights, often referred to as Miranda rights.

Getting Legal Help

If you have been charged with a crime after being stopped at a police roadblock, you can contact a local criminal defense attorney for legal advice. An attorney well-versed in the criminal laws of your area will assess the legality of the roadblock and the circumstances of the stop.

For general traffic violation questions, you can contact a traffic ticket attorney.

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