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Roadblocks: What types of Roadblocks allowed?

08th June 2006
By Darren Kavinoky in Legal
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What types of Roadblocks allowed?

Roadblocks have been established to be "seizures" under the Fourth Amendment. The Fourth Amendment states that a person should be free from unreasonable searches and seizures of their person and their belongings, absent individualized suspicion of wrongdoing. The touchstone for all issues under the Fourth Amendment is reasonableness. Federal constitutional principles require a showing of either the officer's reasonable suspicion that a crime has occurred or is occurring or alternatively that the seizure is carried out pursuant to a plan embodying explicit, neutral limitations on the conduct of individual officers. California constitutional principles are based on the same considerations. That is, balancing the governmental interests served against the intrusiveness of the detention. In California, in order to justify an investigative stop or detention, absent a warrant, there must be probable cause. Probable cause are those circumstances known or apparent to the officer must include specific and articulable facts causing him or her to suspect that some crime has or will take place, and the person stopped is somehow involved in that activity. Reasonableness requires that anyone in the police officer's position would have come to the same conclusion.

However, not all searches and seizures require a reasonable suspicion of criminal activity. Searches conducted as part of a regulatory scheme in furtherance of an administrative purpose, rather than as part of a criminal investigation to secure evidence of a crime, may be permissible under the Fourth Amendment, even absent a showing of probable cause. The reasonableness of an administrative screening is determined by balancing the public interest against the intrusion on the individual. It is under this philosophy, that some types of roadblocks have been determined to be legal while other types of roadblocks are not.

DUI Roadblocks

DUI roadblocks have been determined to be part of a regulatory scheme in furtherance of an administrative purpose, and not traditional criminal investigative stops. The primary purpose of a sobriety roadblock is to promote public safety by deterring intoxicated drivers from driving on public streets and highways. Therefore, if the appropriate guidelines have been followed (Ingersoll factors), DUI roadblocks are legal. Essentially, there must be a neutral screening process applicable to all motorists passing by the roadblock which limits the discretion of the officers in deciding who to stop. The intrusiveness on individual motorists must be limited. The detention of motorists is brief, encompassing only a few questions which allow the officer to observe objective signs of intoxication. In addition, officers will shine their flashlights into the vehicle in order to observe any alcoholic beverages. The Supreme Court has ruled that this intrusion on the individual is slight in comparison to the value to society in keeping drunk drivers off the road.

Drug Roadblocks

The Supreme Court holds that roadblocks whose primary purpose is to detect evidence of ordinary criminal activity are unconstitutional, and therefore illegal. Even though drugs are a scourge on society and are responsible for many of society's ills, there isn't the same vehicle-related threat to life and limb that exists with drunk driving. If law enforcement agencies were allowed to detain citizens based on any of the crimes facing society, then the constitutional protections we enjoy today would disappear. Therefore, because the primary purpose of a drug roadblock is to detect evidence of ordinary criminal wrongdoing, it is unconstitutional.

Roadblocks to find Witnesses to a Crime

The United States Supreme Court has held that an "information-seeking" roadblock, where police briefly detain motorists to pass out flyers and ask if they witnessed a crime is constitutional. Illinois v Lidster held that an Illinois roadblock did not violate the Fourth Amendment's prohibition of unreasonable searches and seizures and was constitutional. The checkpoint was reasonable because it advanced a "grave" public interest and only minimally interfered with the liberties afforded by the Fourth Amendment. The police officers in this case were investigating a crime that resulted in a human death by stopping motorists on the same stretch of road, at the same time that the accident occurred, asking motorists briefly whether they had witnessed the crime or had any information, and passed out fliers. The Supreme Court held that information-seeking roadblocks are less likely to provoke anxiety or to prove intrusive. Further, the law ordinarily allows police to seek voluntary cooperation of members of the public in the investigation of a crime. Because the crime they officers were investigating was motorist-related, and the stop itself was brief, it is constitutional.
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About the Author
Occupation: Lawyer
Darren Kavinoky is a Los Angeles-based criminal defense lawyer who practices throughout California. He is the Managing Shareholder of The Kavinoky Law Firm, an 11-lawyer criminal defense firm that handles criminal defense matters exclusively. Darren has provided legal commentary on Larry King Live, the Today Show, Celebrity Justice and many other TV and radio programs. He is a nationally-renowned lecturer and author who delights in sharing his experience with others. More information about Darren and The Kavinoky Law Firm can be found at or and
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